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| C | R | Score | PMID | Date | Au | Ab | Title | Journal |
|---|---|---|---|---|---|---|---|---|
| 1001 | 35.26 | 15274049 | 2005.02.16 | + | + | Association analysis of two candidate phospholipase genes that map to the chromosome 15q15.1-15.3 region associated with reading disability. | Am J Med Genet B Neuropsychiatr Genet | |
| DW Morris, D Ivanov, L Robinson, N Williams, J Stevenson, MJ Owen, J Williams, MC O'Donovan, | ||||||||
| Molecular genetic studies have suggested a reading disability (RD, dyslexia) susceptibility locus on chromosome 15q. We have previously mapped this locus by association to the region surrounding D15S994. Very little is known about the neurobiological processes involved in RD, and therefore selecting positional candidate genes for analysis based upon function is difficult. Nevertheless we were able to identify two functional candidates based upon existing hypotheses. Both were phospholipase genes, phospholipase C beta 2 (PLCB2) and phospholipase A2, group IVB (cytosolic; PLA2G4B). D15S944 is located within PLCB2 and is 1.6 Mb from PLA2G4B. We examined each gene for association using a mixed direct and indirect association approach, a case (n = 164)/control (n = 174) sample, and a partially overlapping sample of 178 RD parent-proband trios from South Wales and England. Mutation analysis revealed 14 sequence variants in PLCB2 and 33 variants in PLA2G4B. All non-synonymous SNPs were genotyped as were SNPs across each gene with maximum distance between SNPs of 6 kb. Case-control analyses revealed modest evidence (0.01 < P < 0.05) for association between a single variant in PLCB2 and two variants in PLA2G4B. However, association was not confirmed in the family based sample. As the latter sample has previously generated replicated significant evidence for association between RD and markers/haplotypes surrounding D15S944, it should have sufficient power to detect association to variants in susceptibility gene itself. We conclude that neither gene accounts for the association signal we previously observed. As these are the only clear cut functional candidate genes in the region, identification of the putative susceptibility locus for RD on 15q will require more methodical non-hypothesis driven positional cloning approaches. | ||||||||
| 1002 | 35.26 | 12354692 | 2002.12.16 | + | + | Essential role of calcium in vascular endothelial growth factor A-induced signaling: mechanism of the antiangiogenic effect of carboxyamidotriazole. | FASEB J | |
| M Faehling, J Kroll, KJ Föhr, G Fellbrich, U Mayr, G Trischler, J Waltenberger, | ||||||||
| Vascular endothelial growth factor-A (VEGF-A) plays a major role in tumor angiogenesis and raises the concentration of intracellular free calcium ([Ca2+]i). Carboxyamidotriazole (CAI), an inhibitor of calcium influx and of angiogenesis, is under investigation as a tumoristatic agent. We studied the effect of CAI and the role of [Ca2+]i in VEGF-A signaling in human endothelial cells. VEGF-A induced a biphasic [Ca2+]i signal. VEGF-A increased the level of intracellular inositol 1,4,5-trisphosphate (IP3), which suggests that VEGF-A releases Ca2+ from IP3-sensitive stores and induces store-operated calcium influx. Reduction of either extracellular or intracellular free Ca2+ inhibited VEGF-A-induced proliferation. CAI inhibited IP3 formation, both phases of the calcium signal, nitric oxide (NO) release, and proliferation induced by VEGF-A. CAI prevented neither activation of VEGF receptor-2 (VEGFR-2) (KDR/Flk-1), phospholipase C-g, or mitogen-activated protein kinase (MAP kinase) nor translocation of nuclear factor of activated T cells (NFAT). We conclude that calcium signaling is necessary for VEGF-A-induced proliferation. MAP kinase activation occurs independently of [Ca2+]i but is not sufficient to induce proliferation in the absence of calcium signaling. Inhibition of the VEGF-A-induced [Ca2+]i signal and proliferation by CAI can be explained by inhibition of IP3 formation and may contribute to the antiangiogenic action of CAI. Calcium-dependent NO formation may represent a link between calcium signaling and proliferation. | ||||||||
| 1003 | 35.26 | 12886034 | 2003.09.02 | + | + | Monoamine oxidase A gene polymorphism, 5-HT 2A receptor gene polymorphism and incidence of nausea induced by fluvoxamine. | Neuropsychobiology | |
| K Yoshida, S Naito, H Takahashi, K Sato, K Ito, M Kamata, H Higuchi, T Shimizu, K Itoh, K Inoue, T Suzuki, T Ohkubo, | ||||||||
| Selective serotonin reuptake inhibitors cause a side effect of nausea with high frequency, but there have been no accurate methods to predict its incidence. The authors first investigated whether a functional polymorphism in the monoamine oxidase A (MAOA-VNTR) and a -1438G/A polymorphism in the promoter region of the 5-HT(2A) gene were associated with the incidence of nausea induced by fluvoxamine. Fluvoxamine was administered for 6 weeks with a specific dosage plan (50-200 mg/day) in 66 Japanese major depressive patients. The frequency of MAOA-VNTR allele 1 was significantly higher in the patients without nausea than in ones with nausea in the statistical analysis including the patients whose plasma levels were below the average and who were considered to be pharmacodynamically more sensitive to nausea. This study showed that the genetic polymorphism of MAOA-VNTR might affect the incidence of nausea induced by SSRIs. If this finding is replicated in other studies with more subjects, MAOA-VNTR polymorphism would be of great clinical use to predict the incidence of nausea induced by SSRIs. | ||||||||
| 1004 | 35.26 | 10581162 | 2000.01.06 | + | + | An important von Hippel-Lindau tumor suppressor domain mediates Sp1-binding and self-association. | Biochem Biophys Res Commun | |
| HT Cohen, M Zhou, AM Welsh, S Zarghamee, H Scholz, D Mukhopadhyay, T Kishida, B Zbar, B Knebelmann, VP Sukhatme, | ||||||||
| VHL is the causative gene for both von Hippel-Lindau (VHL) disease and sporadic clear-cell renal cancer. We showed earlier that VHL downregulates vascular endothelial growth factor transcription by directly binding and inhibiting the transcriptional activator Sp1. We have now mapped the VHL Sp1-binding domain to amino acids 96-122. The 96-122 domain is disproportionately affected by substitution mutations, which interfere with the VHL-Sp1 interaction. Deletion of the 96-122 domain prevents VHL effects on Sp1 DNA binding and on VHL target gene expression, indicating the domain contributes importantly to VHL tumor suppressor activity. Nevertheless, prevention of the VHL-Sp1 interaction only partially abrogates VHL's transcriptional repressor activity, supporting the existence of VHL transcriptional effectors in addition to Sp1. VHL also directly interacts with the Sp1 zinc fingers and self-associates via the 96-122 domain, which furthermore suggest the domain may bind other metalloproteins and contribute to VHL dominant-negative effects. | ||||||||
| 1005 | 35.25 | 8950407 | 1997.03.11 | + | + | Association study of schizophrenia and the dopamine D3 receptor gene locus in two independent samples. | Am J Med Genet | |
| VL Nimgaonkar, AR Sanders, R Ganguli, XR Zhang, J Brar, W Hogge, WE Fann, PI Patel, A Chakravarti, | ||||||||
| Using a case-control design, an association of schizophrenia with the dopamine D3 receptor gene (D3RG) locus was investigated. Initial analysis of pooled results from published studies revealed a significant excess of individuals homozygous for either allele among the patients. The association was next tested in two cohorts ascertained independently at Pittsburgh, Pennsylvania and at Houston, Texas. The Pittsburgh sample was comprised of patients with schizophrenia (DSM-III-R) (n = 130). The controls belonged to two groups: adults screened for the absence of substance abuse or major psychiatric illness (n = 128), and neonates (n = 160). Multivariate analysis suggested an association with allele 1 of the biallelic D3RG polymorphism in comparison with the adult, but not the neonatal, controls. The association was most marked among Caucasian patients with a family history of schizophrenia (odds ratio 13.69, confidence intervals 1.80, 104.30). Survival analysis suggested an earlier age of onset among male patients homozygous for allele 2. The Houston cohort included Caucasian patients with schizophrenia or schizoaffective disorder (DSM-III-R criteria, n = 50), and normal controls matched for gender (n = 51). In this group, no significant associations were noted among all the patients or among subgroups of patients based on family history or age of onset. Possible reasons for the discordant results are discussed. | ||||||||
| 1006 | 35.24 | 10471075 | 1999.10.14 | + | Detection of cytochrome P450 1B1 Bfr I polymorphism: genotype distribution in healthy German individuals and in patients with colorectal carcinoma. | Pharmacogenetics | ||
| E Fritsche, T Brüning, C Jonkmanns, Y Ko, HM Bolt, J Abel, | ||||||||
| 1007 | 35.23 | 12851703 | 2004.03.04 | + | + | Analysis of single nucleotide polymorphism C3435T of the multidrug resistance gene MDR1 in acute lymphoblastic leukemia. | Int J Oncol | |
| T Efferth, A Sauerbrey, D Steinbach, E Gebhart, HG Drexler, H Miyachi, CR Chitambar, CM Becker, F Zintl, A Humeny, | ||||||||
| Multidrug resistance is an important mechanism responsible for refractoriness of leukemia and worse outcome of patients. Overexpression of the multidrug resistance gene, MDR1, is of prognostic relevance in acute myeloid leukemia, while its role in acute lymphoblastic leukemia (ALL) is still under debate. Single nucleotide polymorphisms (SNP) have been detected in the MDR1 gene. The C3435T polymorphism in this gene seems to have functional and clinical consequences. In the present investigation, we have analyzed the role of the C3435T SNP for drug resistance and prognosis of human ALL. The C3435T SNP was analyzed in 20 T-ALL cell lines and in blood samples from 53 ALL patients and 7 healthy donors. The cell line panel consisted of cell lines not prior exposed in vitro to cytostatic drugs as well as of drug-resistant lines which were selected in vitro by exposure to doxorubicin, vincristine, methotrexate, or hydroxyurea. We have developed a highly sensitive matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based genotyping approach to survey the C3435T SNP. Furthermore, mRNA expression was determined by real time reverse-transcribed polymerase chain reaction and doxorubicin sensitivity by a growth inhibition assay. Surprisingly, we did not find a significant correlation between C3435T homo- or heterozygote genotypes and MDR1 mRNA expression of cell lines or blood samples from patients and healthy donors. Furthermore, there was no relationship between the response of the cell lines to doxorubicin and the C3435T genotypes. Homo- or heterozygosity did not correlate to survival of patients in the Kaplan-Meier analysis. In conclusion, we do not have reason to assume that the C3435T SNP contributes to drug resistance of ALL and prognosis of ALL patients. | ||||||||
| 1008 | 35.23 | 16002074 | 2006.05.30 | + | + | The association of common SNPs and haplotypes in the CETP and MDR1 genes with lipids response to fluvastatin in familial hypercholesterolemia. | Atherosclerosis | |
| D Bercovich, Y Friedlander, S Korem, A Houminer, A Hoffman, L Kleinberg, C Shochat, E Leitersdorf, V Meiner, | ||||||||
| OBJECTIVE: To examine whether genetic polymorphisms in the cholesteryl-ester transfer protein (CETP) and the P-glycoprotein drug transporter (MDR1), are associated with variable lipid response to fluvastatin. METHODS: Lipid levels were determined in a compliance-monitored clinical study at baseline and following 20 weeks of treatment with 40 mg dose of fluvastatin in 76 FH patients. CETP and MDR1 SNP genotyping was performed and linear regression was used to examine the associations between common SNPs and haplotypes and lipid response. RESULTS: Treatment with 40 mg of fluvastatin resulted in mean low density lipoprotein cholesterol (LDL-C) reduction of 21.5%; mean triglyceride (TG) reduction of 8.3%; and a mean high-density lipoprotein cholesterol (HDL-C) increase of 13.4%. Five tagging SNPs in both genes were used to reconstruct five and six haplotypes accounting for 71.4% and 90.2% of the observed haplotypes in the CETP and MDR1 genes, respectively. CETP-H13 and MDR1-h4 were associated with an increase in LDL-C response. CETP-H5 was significantly associated with decreased TG and HDL-C response, whereas MDR1-h10 was associated with decreased TG response. A multivariate regression model indicated an independent additive effect of CETP-H5 and MDR1-h10 on the level of TG response. CONCLUSIONS: CETP and MDR1 have independent effects on lipid changes following fluvastatin treatment. The results of this study may lead to an improved understanding of the genetic determinants of lipids response to treatment. | ||||||||
| 1009 | 35.22 | 12235278 | 2002.10.21 | + | + | A cell-based reporter gene assay for determining induction of CYP3A4 in a high-volume system. | J Pharmacol Exp Ther | |
| J Raucy, L Warfe, MF Yueh, SW Allen, | ||||||||
| Assessing the inducibility of CYP3A4 by various xenobiotics can predict potential drug interactions. In the present investigation, human hepatoma cells were stably integrated with either the CYP3A4 enhancer region and a luciferase reporter gene or the CYP3A4-luciferase construct and the human pregnane X receptor (PXR). Several colonies containing one to three copies of luciferase per cell were identified by Southern blot analysis. Those transformants producing high luciferase activity in response to rifampicin were used to standardize a 96-well plate screening system with minimal inter- and intraplate variability. Standardization also consisted of assessing viability of cells cultured in medium containing various serum concentrations. In cells maintained for 48 h in medium with less than 5% serum, a significant (p < 0.01) decline was observed in viability accompanied by altered induction. A defined serum-free medium also produced less viable cells but did not alter the inductive response. Treatment of transformants with various concentrations of rifampicin produced a dose-response curve with maximal induction at 10 microM (5.6 +/- 0.18- and 2.1 +/- 0.3-fold above dimethyl sulfoxide (DMSO)-treated cells in transformants with and without PXR, respectively). Of additional agents examined for their ability to induce CYP3A4, omeprazole (200 microM) was the most potent inducer (12.8 +/- 1.9- and 2.4 +/- 0.2-fold above DMSO-treated cells in transformants with and without PXR, respectively). Mifepristone and mevastatin produced modest induction (approximately 3-fold) in the cell line containing exogenous PXR, but produced less than 1.2-fold increases in cells lacking PXR. Thus, only potent inducers can be identified in the cell line without PXR. In contrast, cells containing the receptor can be used to rank CYP3A4 induction. Because a high volume of chemicals can be readily and accurately screened for their ability to induce CYP3A4 with this format, such a system could be valuable in the initial stages of preclinical drug development. | ||||||||
| 1010 | 35.22 | 14645853 | 2003.12.18 | + | + | Mutation of MEF2A in an inherited disorder with features of coronary artery disease. | Science | |
| L Wang, C Fan, SE Topol, EJ Topol, Q Wang, | ||||||||
| The early genetic pathway(s) triggering the pathogenesis of coronary artery disease (CAD) and myocardial infarction (MI) remain largely unknown. Here, we describe an autosomal dominant form of CAD/MI (adCAD1) that is caused by the deletion of seven amino acids in transcription factor MEF2A. The deletion disrupts nuclear localization of MEF2A, reduces MEF2A-mediated transcription activation, and abolishes synergistic activation by MEF2A and by the transcription factor GATA-1 through a dominant-negative mechanism. The MEF2A protein demonstrates strong expression in the endothelium of coronary arteries. These results identify a pathogenic gene for a familial vascular disease with features of CAD and implicate the MEF2A signaling pathway in the pathogenesis of CAD/MI. | ||||||||
| 1011 | 35.21 | 17429314 | 2007.05.29 | + | + | Influence of the UGT2B7 promoter region and exon 2 polymorphisms and comedications on Acyl-MPAG production in vitro and in adult renal transplant patients. | Pharmacogenet Genomics | |
| N Djebli, N Picard, JP Rérolle, Y Le Meur, P Marquet, | ||||||||
| INTRODUCTION: The polymorphic enzyme UGT2B7 metabolizes mycophenolic acid into acyl-mycophenolic acid-glucuronide (AcMPAG), a presumably toxic metabolite. This study aimed at investigating in vitro and in vivo the impact on AcMPAG production of: (i) the UGT2B7 gene G-842A single nucleotide polymorphism, in complete linkage disequilibrium with most other known single nucleotide polymorphisms in the promoter region of this gene and with the C802T single nucleotide polymorphism in exon 2 (UGT2B*2); and (ii) of the other immunosuppressants given to renal transplant patients in association with mycophenolate mofetil. METHODS: We compared the production of AcMPAG by human liver microsomes genotyped for the UGT2B7 G-842A and C802T single nucleotide polymorphisms, and plasma AcMPAG concentrations in genotyped renal transplant patients administered mycophenolate mofetil associated with sirolimus (n=40), tacrolimus (n=24) or cyclosporin (n=28) and decreasing doses of corticosteroids, over the first 3 months after transplant. The effect of corticosteroids was also investigated in vitro using rats' liver microsomes. RESULTS: The two polymorphisms studied were in complete reverse linkage disequilibrium. AcMPAG production was 1.25 and 1.56-fold higher in G-842A and -842AA human liver microsomes, respectively, compared with GG-842 human liver microsomes (P=0.01). Enzyme kinetics showed 1.4 and 3.7-fold higher Vmax in the respective pools of human liver microsomes. Km values were 0.20, 0.25 and 0.44 mmol/l for the GG-842, G-842A and -842AA genotypes, respectively. This clear increase in Vmax is in favor of the implication of the promoter region polymorphisms, whereas the slighter increase in Km might be due to the UGT2B7*2 single nucleotide polymorphism. Consistently, the UGT2B7 genotype significantly influenced AcMPAG area under the curve (AUC0-9 h)/dose in patients on sirolimus at months 1 and 3 after transplant (P=0.04 for both). No effect was observed in patients on tacrolimus and possibly also on cyclosporin, maybe owing to pharmacokinetic interaction with mycophenolate. AcMPAG production was increased in corticosteroid-induced rat liver microsomes, consistent with the observed in-vivo decrease of mycophenolic acid metabolites AUC0-9 h/dose with time after transplant. CONCLUSION: Both UGT2B7 polymorphisms and co-medications significantly influenced AcMPAG production, but cyclosporin and tacrolimus hindered the phenotypic impact of this trait. | ||||||||
| 1012 | 35.20 | 11317357 | 2001.08.30 | + | + | Spectrum of germline RB1 gene mutations in Spanish retinoblastoma patients: Phenotypic and molecular epidemiological implications. | Hum Mutat | |
| J Alonso, P García-Miguel, J Abelairas, M Mendiola, E Sarret, MT Vendrell, A Navajas, A Pestaña, | ||||||||
| Mutation analysis of retinoblastoma is considered important for genetic counseling purposes, as well as for understanding the molecular mechanisms leading to tumors with different degrees of penetrance or expressivity. In the course of an analysis of 43 hereditary retinoblastoma Spanish patients and kindred, using direct PCR sequencing, we have observed 29 mutations; most of them (62%) have not been reported previously. Of the mutations, 69% correspond to nonsense mutations (mainly CpG transitions) and frameshifts, with the expected outcome of a truncated Rb protein that lacks the functional pocket domains and tail. The remainder corresponds to splicing mutations, most of them (62%) targeted to invariant nucleotides, with the predicted consequence of out of frame exon skipping. Two of the splicing mutations in our study were found associated to families with a low-penetrance phenotype. Additionally, most of the mutations affecting splice junctions corresponded to retinoblastoma cases of either sporadic or hereditary nature with delayed onset (32 months on average). In contrast, most of the nonsense and frameshift mutations are associated with an early age at diagnosis (8.7 months on average). These differences are discussed in the context of the relationships between genotype and low expressivity phenotype. The differences in the spectrum of RB1 mutations found in this and other European surveys are also discussed in the context of alternate DNA methylation and mismatch repair phenotypes. | ||||||||
| 1013 | 35.19 | 10528242 | 1999.12.01 | + | + | Linkage disequilibrium of MTHFR genotypes 677C/T-1298A/C in the German population and association studies in probands with neural tube defects(NTD). | Am J Med Genet | |
| K Stegmann, A Ziegler, ET Ngo, N Kohlschmidt, B Schröter, A Ermert, MC Koch, | ||||||||
| A number of studies have demonstrated that the common polymorphism 677C-->T in the gene encoding 5, 10-methylenetetrahydrofolate reductase (MTHFR) leads to a thermolabile variant with decreased enzyme activity and to mildly elevated plasma homocysteine. 677TT homozygosity was shown to be more frequent in NTD probands compared with controls in some studies. Recently, another polymorphism, 1298A-->C, in the MTHFR gene was described and combined heterozygosity 677CT/1298AC was suggested to be an additional risk factor for NTD. The present study examines the genotype and haplotype distribution of the two polymorphisms in the German population and evaluates the impact on NTD individuals and their relatives. To determine the haplotype of all individuals tested, we developed an easy-to-perform ARMS-RFLP test. Our data show that the two polymorphisms are in linkage disequilibrium in the general population and in NTD individuals. There was no statistically significant difference in allele and genotype frequency between probands (patients, fetuses) and controls (P > 0.10) and between observed and expected values for mother-child pairs (P > 0.80). Taking into account gender, an increased rate of 677CT heterozygotes was found in affected and unaffected males compared to affected and unaffected females. A family-based association study using a multiallelic transmission disequilibrium test (TDT) also shows that transmission rates do not deviate significantly from equilibrium (P > 0.50). Thus, our data provide no evidence for an association between NTD phenotype and MTHFR 677C/T-1298A/C genotypes and haplotypes. | ||||||||
| 1014 | 35.18 | 12455060 | 2003.01.06 | + | + | SULT1A1 polymorphism and esophageal cancer in males. | Int J Cancer | |
| MT Wu, YT Wang, CK Ho, DC Wu, YC Lee, HK Hsu, EL Kao, JM Lee, | ||||||||
| Sulfotransferase (SULT) 1A1 detoxifies and bioactivates a broad spectrum of substrates including xenobiotics. It has been suggested that the SULT1A1 his (histidine) allele, which is caused by a his for arg (arginine) substitution due to a G-->A transition at codon 213, carries a significantly higher risk for women to develop breast cancer. We investigated the association between the SULT1A1 arg/his genotype and esophageal cancer in men, 187 cases of esophageal squamous cell carcinoma and 308 controls from 3 medical centers in Taiwan. Cigarette smoking, areca chewing and alcohol consumption were the major risks for developing esophageal cancer. The frequencies of arg/his in cases and controls were 27.8% (52/187) and 11.0% (34/308), respectively (p < 0.0001). No subjects carried his/his. After adjusting for substance use and other covariates, individuals with arg/his had a 3.53-fold higher risk (95% CI = 2.12-5.87) of developing esophageal cancer than those with arg/arg. Unexpectedly, this positive association was found to be even stronger (adjusted OR = 4.04-4.80) among non-smokers, non-drinkers or non-chewers. Our findings suggest that the SULT1A1 his(213) allele is important in the development of esophageal cancer in men. | ||||||||
| 1015 | 35.18 | 10903844 | 2000.08.29 | + | + | Human EMR2, a novel EGF-TM7 molecule on chromosome 19p13.1, is closely related to CD97. | Genomics | |
| HH Lin, M Stacey, J Hamann, S Gordon, AJ McKnight, | ||||||||
| The epidermal growth factor (EGF)-TM7 proteins [EMR1, (EGF-like molecule containing mucin-like hormone receptor 1) F4/80, and CD97] constitute a recently defined class B GPCR subfamily and are predominantly expressed on leukocytes. These molecules possess N-terminal EGF-like domains coupled to a seven-span transmembrane (7TM) moiety via a mucin-like spacer domain. Genomic mapping analysis has suggested a possible EGF-TM7 gene family on the human chromosome 19p13 region. In this study, a new member of the EGF-TM7 family, EMR2, which shares strikingly similar molecular characteristics with CD97, is described. In addition to mapping closely to CD97 on human chromosome 19p13.1, EMR2 contains a total of five tandem EGF-like domains and expresses similar protein isoforms consisting of various numbers of EGF-like domains as a result of alternative RNA splicing. Furthermore, EMR2 and CD97 exhibit highly homologous EGF-like domains and share identical gene organization, indicating that both genes are the products of a recent gene duplication event. The homologous EGF-like domains enable the identification of both EMR2 and CD97 by monoclonal antibodies (mAbs) raised against the first EGF-like domain of CD97, whereas mAbs directed against the extracellular spacer domain of CD97 are able to differentiate these two proteins. Both EMR2 and CD97 are highly expressed in immune tissues; however, unlike CD97, which is ubiquitously expressed in most cell types, EMR2 expression is restricted to monocytes/Mφ and granulocytes. EMR2 fails to interact with CD55, the cellular ligand for CD97, suggesting the possibility of a different cellular ligand(s). EMR2 may therefore have a unique function in cells of monocyte/Mφ and granulocyte lineages. | ||||||||
| 1016 | 35.17 | 16434604 | 2006.04.04 | + | + | Combined effects of the p53 and p73 polymorphisms on lung cancer risk. | Cancer Epidemiol Biomarkers Prev | |
| MB Schabath, X Wu, Q Wei, G Li, J Gu, MR Spitz, | ||||||||
| Lung cancer is a multigenic disease where one variant single nucleotide polymorphism may have only a modest independent effect on the disease phenotype, yet in aggregate, multiple biologically relevant single nucleotide polymorphisms may provide a more accurate representation of risk. Polymorphisms in members of the p53 family, such as p53 and p73, that have a functional relevance would be predicted to contribute to the disease phenotype. In this analysis, we used genotype data from 863 lung cancer cases and 852 healthy controls to test for multigenetic effects of polymorphisms at p53 exon 4, introns 3 and 6, and at p73 exon 2. All individuals in this analysis were self-reported non-Hispanic Caucasians. When the p73 and p53 variant alleles were combined and analyzed as a continuous variable, there was a 13% increase [odds ratios (OR), 1.13; 95% confidence intervals (CI), 1.05-1.21] in lung cancer risk for each additional variant allele. Furthermore, when the number of variant alleles was categorized into three groups (zero, one to three, and four or more variants), there was evidence of a gene-dosage effect with increased risks for individuals with one to three variants (OR, 1.30; 95% CI, 1.05-1.61) and four or more variants (OR, 1.78; 95% CI, 1.23-2.56). When the data were stratified by smoking status, an increased risk for lung cancer was evident only in current (OR, 2.32; 95% CI, 1.25-4.33) and former smokers (OR, 1.73; 95% CI, 1.02-2.94) with four or more variants. Younger individuals with four or more variants were also at a significantly increased risk for lung cancer (OR, 3.15; 95% CI, 1.62-6.12). This study provides support for the multigenetic effects of variant alleles from p53 exon 4, and introns 3 and 6, and p73, and their interplay with smoking, resulting in a significantly increased risk for lung cancer in this Caucasian population. | ||||||||
| 1017 | 35.17 | 12675692 | 2003.10.14 | + | + | Estimation of multilocus haplotype effects using weighted penalised log-likelihood: analysis of five sequence variations at the cholesteryl ester transfer protein gene locus. | Ann Hum Genet | |
| MW Tanck, AH Klerkx, JW Jukema, P De Knijff, JJ Kastelein, AH Zwinderman, | ||||||||
| Direct analyses of haplotype effects can be used to identify those specific combinations of alleles that are associated with a specific phenotype. We introduce a method for direct haplotype analysis that solves two problems that arise when haplotypes are analysed in populations of unrelated subjects. Instead of assigning a single, most likely, haplotype pair to multiple heterozygous subjects, all haplotype pairs compatible with their genotype were determined and the posterior probabilities of these pairs were calculated using Bayes' theorem and estimated haplotype frequencies. For the individual patients, all possible haplotype pairs were included in the statistical analysis using the posterior probabilities as weights, which were re-estimated in an iterative process together with the haplotype effects. The second problem of unstable haplotype effect estimates, due to the numerous haplotypes and the low frequency at which some occur, was solved by assuming that haplotypes sharing the same alleles show a similar effect and that the extent of this similarity relates to the number of alleles shared. These assumptions were incorporated in a weighted log-likelihood model by introducing a penalty, where differences in effects of similar haplotypes were penalised. Using CETP gene haplotypes, consisting of five closely linked polymorphisms, and baseline CETP and HDL-C concentrations from the REGRESS population, we demonstrated that the model resulted in more stable effects than estimates based on unambiguous patients only. | ||||||||
| 1018 | 35.17 | 12543786 | 2003.03.13 | + | + | BRCA1 and BRCA2 mutation status and tumor characteristics in male breast cancer: a population-based study in Italy. | Cancer Res | |
| L Ottini, G Masala, C D'Amico, B Mancini, C Saieva, G Aceto, D Gestri, V Vezzosi, M Falchetti, M De Marco, M Paglierani, A Cama, S Bianchi, R Mariani-Costantini, D Palli, | ||||||||
| To investigate at the population level the impact of BRCA1/BRCA2 gene alterations in male breast cancer, we analyzed a population-based series of 25 male breast cancer cases from Florence, Central Italy. We combined mutational screening with the study of germ-line allele transcript levels and of tumor-associated losses of heterozygosity. Screening by protein truncation test and single-strand conformational polymorphism assay, followed by sequencing, revealed 4 pathogenetic mutations (4 of 25 = 16%; 95% confidence interval, 5-37%), 1 in BRCA1 and 3 in BRCA2, including mutations recurring in Central Italy (BRCA1 3345delAG and BRCA2 6696delTC). The a priori probability of carrying a mutation, estimated using BRCAPRO software, showed a good agreement between expected and observed mutations (14% versus 16%). A 7-fold association between germ-line mutations and family history of breast-ovarian cancer emerged. To investigate associations between BRCA1/BRCA2 status and clinicopathological characteristics, we analyzed the histopathological and immunophenotypic parameters of the tumors. A significant association emerged between mutation carrier status and high histological grade (P = 0.02). Furthermore, one BRCA2 carrier was affected with Paget's disease, an extremely rare male breast cancer histotype. Overall, BRCA1/2 mutations were observed to be strongly associated with positive c-erbB-2 immunostaining (P = 0.004). To evaluate germ-line allele expression, we used primer extension assays targeting frequent BRCA1 and BRCA2 polymorphisms. A BRCA2 allele transcript imbalance was found in one of four heterozygotes tested, all of them negative for germ-line mutations. BRCA1 transcript imbalances were not detected in nine heterozygotes analyzed. Losses of heterozygosity at one or more of nine loci in the BRCA2 region were found in 8 of 22 tumors tested. Interestingly, a case that was negative for BRCA1/BRCA2 germ-line mutations and that had a priori mutation probability <10% showed loss of heterozygosity at all three of the intragenic BRCA2 markers analyzed, which could be related to a somatic involvement of BRCA2. No losses of heterozygosity were detected at BRCA1. In conclusion, constitutional BRCA1/BRCA2 mutations accounted for 16% of the male breast cancer cases in this area of Central Italy. The detection of a BRCA2 germ-line transcript imbalance and of a somatic loss of BRCA2 among the cases that resulted negative for germ-line mutations suggests a role of this gene more relevant than indicated by conventional mutational analysis. A distinct pattern of characteristics indicative of aggressive behavior, including high-grade and c-erbB-2 expression, was evident in tumors from germ-line BRCA2 mutation carriers. This suggests that phenotypic characteristics may contribute to the identification of hereditary BRCA2-related male breast cancers and that these tumors might share a unique molecular pathway of cancer progression. | ||||||||
| 1019 | 35.16 | 16941663 | 2007.02.27 | + | + | Association between polymorphisms in serotonin transporter gene and attention deficit hyperactivity disorder in Chinese Han subjects. | Am J Med Genet B Neuropsychiatr Genet | |
| J Li, Y Wang, R Zhou, H Zhang, L Yang, B Wang, SV Faraone, | ||||||||
| Prior work has shown reduced serotonin transmission to be associated with impulsivity and behavioral problems. The current study assessed the association between ADHD and two variants of the serotonin transporter gene: the 44-bp deletion/insertion polymorphism (5-HTTLPR) and the 17 bp-repeat polymorphism in intron 2 (STin2.VNTR). We hypothesized that ADHD phenotypes associated with impulsivity would show an association with these variants. Two-hundred and ninety-three ADHD trios were genotyped and analyzed using transmission disequilibrium test (TDT) analysis and haplotype analysis. We found no association between the STin2.VNTR and ADHD, but did find preferential transmission of the S allele of the 5-HTTLPR polymorphism (chi(2) = 5.751, P = 0.016) to probands with ADHD. Haplotype analysis found the L/10 haplotype was over-transmitted (chi(2) = 6.172, P = 0.013), while L/12 was under-transmitted to probands with ADHD (chi(2) = 4.866, P = 0.027). | ||||||||
| 1020 | 35.16 | 16103896 | 2005.12.29 | + | + | An association study of 43 SNPs in 16 candidate genes with atorvastatin response. | Pharmacogenomics J | |
| JF Thompson, M Man, KJ Johnson, LS Wood, ME Lira, DB Lloyd, P Banerjee, PM Milos, SP Myrand, J Paulauskis, MA Milad, WJ Sasiela, | ||||||||
| Variation in individual response to statin therapy has been widely studied for a potential genetic component. Multiple genes have been identified as potential modulators of statin response, but few study findings have replicated. To further examine these associations, 2735 individuals on statin therapy, half on atorvastatin and the other half divided among fluvastatin, lovastatin, pravastatin and simvastatin were genotyped for 43 SNPs in 16 genes that have been implicated in statin response. Associations with low-density lipoprotein cholesterol (LDL-C) lowering, total cholesterol lowering, HDL-C elevation and triglyceride lowering were examined. The only significant associations with LDL-C lowering were found with apoE2 in which carriers of the rare allele who took atorvastatin lowered their LDL-C by 3.5% more than those homozygous for the common allele and with rs2032582 (S893A in ABCB1) in which the two groups of homozygotes differed by 3% in LDL-C lowering. These genetic effects were smaller than those observed with the demographic variables of age and gender. The magnitude of all the differences found is sufficiently small that genetic data from these genes should not influence clinical decisions on statin administration. | ||||||||
| 1021 | 35.15 | 10208450 | 1999.06.15 | + | + | Polymorphisms of the interleukin-1 gene complex in schizophrenia. | Mol Psychiatry | |
| H Katila, K Hänninen, M Hurme, | ||||||||
| Activation of the inflammatory response system has been related to the pathophysiology of schizophrenia by several recent studies. Schizophrenic patients have varied levels of proinflammatory cytokines, such as interleukin (IL)-1, -6, and tumor necrosis factor (TNF)alpha in their peripheral blood or cerebrospinal fluid. These cytokines can modify the metabolism of neurotransmitters, influence neural development, and IL-1 has been implicated in acute, and, on the other hand, chronic neurodegeneration. They could therefore be of primary pathogenic importance, either in the acute disease or during those stages of brain development which possibly influence the sensitivity of a person to schizophrenia in later life. The cytokine regulation of brain development and its possible neuroimmune involvement in the pathogenesis of schizophrenia has been raised. One indication of the pathogenic role of IL-1 in schizophrenia would be a demonstration of the difference between schizophrenic patients and healthy controls at the gene level. Therefore we analyzed the polymorphism of the IL-1 gene complex in 50 schizophrenic patients and in 400 healthy blood donors. The following allelisms were analyzed: IL-1beta gene: base exchange polymorphisms at the positions -511 (relative to the transcriptional start site); IL-1alpha gene: base exchange polymorphism at the position -889; IL-1 receptor antagonist (IL-1RA) gene: variable numbers of 86-base pair tandem repeats in intron 2. The frequencies of the IL-1beta (-511) allele 1, IL-1alpha (-889) allele 2, and IL-1RA allele 1 were somewhat, but not significantly, higher in the schizophrenic patients as compared to the controls. These alleles are known to be located on the same haplotype. The number of carriers of this haplotype was significantly higher in the schizophrenia patients (17/50 vs 81/400) than in the controls (P=0.026, chi2). The frequencies of this haplotype were 0.38 and 0.27, respectively (P=0.0266, chi2). The number of homozygotes of this haplotype was significantly higher in the schizophrenia patients (P=0.0006, chi2). These data suggest that the cytokine aberrations in schizophrenia are, at least partly, genetically determined. | ||||||||
| 1022 | 35.14 | 15571265 | 2005.02.03 | + | + | Mutation in the ITPA gene predicts intolerance to azathioprine. | Nucleosides Nucleotides Nucleic Acids | |
| AM Marinaki, JA Duley, M Arenas, A Ansari, S Sumi, CM Lewis, M Shobowale-Bakre, LD Fairbanks, J Sanderson, | ||||||||
| Inosine triphosphate pyrophosphatase (ITPase) deficiency occurs with polymorphic frequencies in Caucasians and results in the benign accumulation of the inosine nucleotide ITP. In 62 patients treated with azathioprine for inflammatory bowel disease, the ITPA 94C>A deficiency-associated allele was significantly associated with adverse drug reactions (OR 4.2, 95% CI 1.6-11.5, p = 0.0034). Significant associations were found for flu-like symptoms (OR 4.7, 95% CI 1.2-18.1, p = 0.0308), rash (OR 10.3, 95% CI 4.7-62.9, p = 0.0213) and pancreatitis (OR 6.2, CI 1.1-32.6, p = 0.0485). Polymorphism in the ITPA gene thus predicts AZA intolerance. Alternative immunosuppressive drugs, particularly 6-thioguanine, should be considered for AZA-intolerant patients with ITPase deficiency. | ||||||||
| 1023 | 35.14 | 11032386 | 2001.02.01 | + | + | A family-based and case-control association study of the dopamine D4 receptor gene and dopamine transporter gene in attention deficit hyperactivity disorder. | Mol Psychiatry | |
| J Holmes, A Payton, JH Barrett, T Hever, H Fitzpatrick, AL Trumper, R Harrington, P McGuffin, M Owen, W Ollier, J Worthington, A Thapar, | ||||||||
| Attention deficit hyperactivity disorder (ADHD) is a highly heritable psychiatric condition of early childhood onset characterised by marked inattention, hyperactivity and impulsiveness. Molecular genetic investigations of ADHD have found positive associations with the 480-bp allele of a VNTR situated in the 3' untranslated region of DAT1 and allele 7 of a VNTR in exon 3 of DRD4. A number of independent studies have attempted to replicate these findings but the results have been inconsistent. We used both family-based and case control approaches to examine these polymorphisms in a sample of 137 children diagnosed with ICD-10, DSM-IV or DSM-III-R ADHD. We found no evidence of association with the DAT1 polymorphism, despite a sample size that has up to 80% power to detect a previously reported effect size. We observed a significant increase in the DRD4 7 repeat allele amongst ADHD probands (21.7%) and their parents (18.9% in mothers, 22.3% in fathers), compared to ethnically matched controls (12.8%). However TDT analysis showed no preferential transmission of allele 7 to ADHD probands. | ||||||||
| 1024 | 35.14 | 9174682 | 1997.08.26 | + | + | Relationship between fluvoxamine pharmacokinetics and CYP2D6/CYP2C19 phenotype polymorphisms. | Eur J Clin Pharmacol | |
| O Spigset, K Granberg, S Hägg, A Norström, R Dahlqvist, | ||||||||
| OBJECTIVE: The purpose of this study was to investigate whether the disposition of fluvoxamine is associated with the CYP2D6 and CYP2C19 phenotype polymorphisms. METHODS: The serum concentration of fluvoxamine was followed for 48 h after oral administration of a single dose of 50 mg fluvoxamine to five poor metabolizers of the CYP2D6 test drug dextromethorphan, five poor metabolizers of the CYP2C19 test drug mephenytoin, and five extensive metabolizers of both test drugs. RESULTS: Poor metabolizers of dextromethorphan had significantly higher areas under the serum concentration-time curve than extensive metabolizers of dextromethorphan (mean 1.31 vs 1.00 mumol.h.l-1). There were no differences between poor and extensive metabolizers of mephenytoin (mean, 1.00 vs 1.15 mumol.h.l-1). CONCLUSION: The results are consistent with a possible minor to moderate role of CYP2D6, but not CYP2C19, in fluvoxamine metabolism. | ||||||||
| 1025 | 35.13 | 12740593 | 2004.02.20 | + | Further evidence for a modulation of Novelty Seeking by DRD4 exon III, 5-HTTLPR, and COMT val/met variants. | Mol Psychiatry | ||
| A Strobel, KP Lesch, S Jatzke, F Paetzold, B Brocke, | ||||||||
| 1026 | 35.12 | 16865689 | 2006.11.13 | + | + | Identification of novel genes associated with astrocytoma progression using suppression subtractive hybridization and real-time reverse transcription-polymerase chain reaction. | Int J Cancer | |
| J van den Boom, M Wolter, B Blaschke, CB Knobbe, G Reifenberger, | ||||||||
| To identify novel genes involved in glioma progression we performed suppression subtractive hybridization combined with cDNA array analysis on 4 patients with primary low-grade gliomas of World Health Organization (WHO) grade II that recurred as secondary glioblastomas (WHO grade IV). Eight genes showing differential expression between primary and recurrent tumors in 3 of the 4 patients were selected for further analysis using real-time reverse transcription-PCR on a series of 10 pairs of primary low-grade and recurrent high-grade gliomas as well as 42 astrocytic gliomas of different WHO grades. These analyses revealed that 5 genes, i.e., AMOG (ATP1B2, 17p13.1), APOD (3q26.2-qter), DMXL1 (5q23.1) DRR1 (TU3A, 3p14.2) and PSD3 (KIAA09428/HCA67/EFA6R, 8p22), were expressed at significantly lower levels in secondary glioblastomas as compared to diffuse astrocytomas of WHO grade II. In addition, AMOG, DRR1 and PSD3 transcript levels were significantly lower in primary glioblastomas than in diffuse astrocytomas. Treatment of glioma cell lines with 5-aza-2'-deoxycytidine and trichostatin A resulted in increased expression of AMOG and APOD transcripts. Sequencing of sodium bisulfite-modified DNA demonstrated AMOG promoter hypermethylation in the glioma cell lines and 1 primary anaplastic astrocytoma with low AMOG expression. Taken together, we identified interesting novel candidate genes that likely contribute to glioma progression and provide first evidence for a role of epigenetic silencing of AMOG in malignant glioma cells. | ||||||||
| 1027 | 35.11 | 10862079 | 2000.08.11 | + | + | Twenty two novel mutations of the factor VII gene in factor VII deficiency. | Hum Mutat | |
| K Wulff, FH Herrmann, | ||||||||
| Factor VII is a vitamin K-dependent coagulation protease essential for the initiation phase of normal hemostasis. The human factor VII gene (FVII, also known as F7) spans 13 kb and is located on chromosome 13, 2.8 kb upstream of the factor X gene. In the Greifswald FVII deficiency study the molecular basis for inherited factor VII was investigated. All exons, exon-intron boundaries and the promotor of the FVII gene were amplified by PCR and directly sequenced. 87 unrelated probands with reduced or low FVII activities were investigated. Thirty-four different FVII gene lesions were analyzed in 101 FVII alleles of 77 unrelated probands. Twenty-two of these FVII gene lesions are novel FVII variations. The 34 different lesions comprise 31 point mutations and three small deletions. A transition in the CpG doublet accounted for 12 of the 34 different mutants. Sixteen mutations were noted only once. The missense mutation A294V and the double mutation A294V; 11128delC in exon 8 were by far the most common mutations found in this study. The haplotype of the different mutant FVII alleles were analyzed using six polymorphisms of the FVII gene. The haplotypes were identified in 29 mutant FVII alleles. Five different haplotypes are linked to the mutant FVII alleles. Except for one, the same haplotype was detected in FVII genes with an identical FVII gene mutation. Different haplotypes were identified in two patients with the mutant allele A206T. It is likely that identical mutant FVII alleles with the same haplotype share the same origin. | ||||||||
| 1028 | 35.11 | 9014200 | 1997.04.10 | + | + | Imipramine metabolism in relation to the sparteine oxidation polymorphism--a family study. | Pharmacogenetics | |
| H Madsen, TS Hansen, K Brøsen, | ||||||||
| The relationship between genetic polymorphism and imipramine metabolism has never been studied in a family study. A sparteine/mephenytoin test was carried out in 31 parents and 20 siblings of 18 Danish poor metabolizers of sparteine (PMs). One week later, each subject took 25 mg imipramine followed by urine collection for 24 h. The urinary content of imipramine, desipramine, 2-hydroxy-imipramine and 2-hydroxy-desipramine was assayed by HPLC. There were 10 PMs (20%; 9.8-33%, 95% confidence interval) and 41 extensive metabolizers of sparteine (EMs) among parents and siblings. In 26 of the 28 PMs among probands and relatives, there were concordance between phenotype and genotype: D6-A/D6-D (n = 2), D6-A/D6-B (n = 5), D6-B/(n = 15) or D6-B/D6-D (n = 4). Two PMs were apparently heterozygous (EMs), D6-wt/D6-B. Accordingly, based on the present sample of 28 PMs the specificity of the genotype test was 100% and the sensitivity was 92.9%. Two EMs were homozygous dominant D6-wt/and 39 were heterozygous EMs; D6-wt/D6-D (n = 5), D6-wt/D6-B (n = 27), D6-wt/D6-A (n = 6), D6-wt/D6-wt* (unknown mutation) (n = 1). As previously reported in a population study the hydroxylation ratios (i.e. 2-hydroxymetabolite over parent compound) of imipramine were much lower in PMs than in EMs. This and the pedigrees confirmed the co-segregation of sparteine oxidation, imipramine 2-hydroxylation and the CYP2D6 genotype. None of the hydroxylation ratios could separate EMs and PMs completely, mainly because the 2-hydroxylation of imipramine also depends on P450s other than CYP2D6. | ||||||||
| 1029 | 35.10 | 17178637 | 2007.05.21 | + | + | Genetic polymorphisms involved in toxicant-metabolizing enzymes and the risk of chronic benzene poisoning in Chinese occupationally exposed populations. | Xenobiotica | |
| Y Chen, G Li, S Yin, J Xu, Z Ji, X Xiu, L Liu, D Ma, | ||||||||
| Benzene is a recognized haematotoxin and leukaemogen, but its mechanism of action and the role of genetic susceptibility are still unclear. Cytochrome P450 2E1 (CYP2E1) and myeloperoxidase (MPO) are involved in benzene activation; and NAD (P)H:quinine oxidoreductase 1 (NQO1), glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase mu 1 (GSTM1) participate in benzene detoxification. The common, well-studied single-nucleotide polymorphisms (SNPs) were analysed in these genes drawn from the toxicant-metabolizing pathways. A total of 100 workers with chronic benzene poisoning (CBP) and 90 controls were enrolled in China. There was a 2.82-fold (95% CI = 1.42-5.58) increased risk of CBP in the subjects with the NQO1 609C > T mutation genotype (T/T) compared with those carrying heterozygous (C/T) and wild-type (C/C). The subjects with the GSTT1 null genotype had a 1.91-fold (95% CI = 1.05-3.45) increased risk of CBP compared with those with GSTT1 non-null genotype. There was no association of CYP2E1 and MPO genotype with CBP. A three genes' interaction showed that there was a 20.41-fold (95% CI = 3.79-111.11) increased risk of CBP in subjects with the NQO1 609C > T T/T genotype and with the GSTT1 null genotype and the GSTM1 null genotype compared with those carrying the NQO1 609C > T C/T and C/C genotype, GSTT1 non-null genotype, and GSTM1 non-null genotype. The study provides evidence of an association of a gene-gene interaction with the risk of CBP. | ||||||||
| 1030 | 35.10 | 15627807 | 2005.04.18 | + | + | Interaction between the tryptophan hydroxylase gene and the serotonin transporter gene in schizophrenia but not in bipolar or unipolar affective disorders. | Neuropsychobiology | |
| J Chotai, A Serretti, C Lorenzi, | ||||||||
| Increasing focus is being given to identify possible combinations of genes related to specific clinical phenotypes. In our sample of 814 patients comprising 114 with schizophrenia, 416 with bipolar affective disorder and 284 with unipolar affective disorder, we studied interactions between the tryptophan hydroxylase (TPH), the serotonin transporter (5-HTTLPR), and the dopamine receptor (DRD4) genes in relation to five major psychiatric symptomatology scores. There was significant interaction between the TPH and the 5-HTTLPR genes. With an increasing number of short (s) alleles of 5-HTTLPR, the scores for delusions, disorganization and negative symptoms were significantly decreasing among subjects having the TPH genotype AA but increasing among subjects having the TPH genotype AC, yielding the highest scores for the combinations AA x ll and AC x ss. Since high scores on just delusions, disorganization and negative symptoms but low scores on excitement and depression were found among subjects with schizophrenia, we conducted comparisons among the three diagnostic categories and controls as regards the combined TPH x 5-HTTLPR genotype distribution. Schizophrenia subjects had a significantly different distribution of the genotype combination for TPH x 5-HTTLPR as compared to 241 controls or to unipolar or bipolar subjects, and had significantly higher frequencies of AA x ll and of AC x ss. Thus, an interaction between TPH and 5-HTTLPR genes constitutes susceptibility to schizophrenia, thereby yielding apparent relationships between the major psychiatric symptomatology scores and genotype combinations in samples that are obtained by pooling schizophrenia with other diagnostic categories. | ||||||||
| 1031 | 35.09 | 15226678 | 2005.03.21 | + | + | Identification of a novel variant CYP2C9 allele in Chinese. | Pharmacogenetics | |
| D Si, Y Guo, Y Zhang, L Yang, H Zhou, D Zhong, | ||||||||
| OBJECTIVES: Cytochrome P450 (CYP) 2C9 metabolizes about 16% of drugs in current clinical use, including lornoxicam and tolbutamide. SNPs in the CYP2C9 gene have increasingly been recognized as determinants of the metabolic phenotype that underlies interindividual and ethnic differences. METHODS: The present study focused on a Chinese poor metabolizer (PM) whose apparent genotype (CYP2C9*1/CYP2C9*3) did not agree with his PM phenotype for both lornoxicam and tolbutamide. By sequencing his CYP2C9 gene, we identified a new variant CYP2C9 allele involving a T269C transversion in exon 2 that leads to a Leu90Pro substitution in the encoded protein. RESULTS: The CYP2C9 genotype analysis in the family of the poor metabolizer showed the new exon 2 change and CYP2C9*3 occurred on different alleles. Thus, the PM status of this subject could be attributed to his being heterozygous for the CYP2C9 T269C allele together with the CYP2C9*3. Frequency analysis in 147 unrelated Chinese males indicated approximately 2% of the Chinese population carry the allele. CONCLUSION: This study suggests that this novel CYP2C9 allele was correlated with reduced plasma clearance of drugs that are substrates for CYP2C9. | ||||||||
| 1032 | 35.08 | 17035386 | 2007.06.20 | + | + | CYP2A6 genotype, phenotype, and the use of nicotine metabolites as biomarkers during ad libitum smoking. | Cancer Epidemiol Biomarkers Prev | |
| V Malaiyandi, SD Goodz, EM Sellers, RF Tyndale, | ||||||||
| CYP2A6 inactivates nicotine to cotinine and cotinine to 3-hydroxycotinine. We investigated which of plasma nicotine and metabolites were most related to CYP2A6 genotype and smoking levels. We assessed demographic and smoking histories in 152 Caucasian ad libitum smokers, measured breath carbon monoxide (CO) levels, and determined plasma nicotine, cotinine, and 3-hydroxycotinine by high-performance liquid chromatography and CYP2A6 genotypes by PCR. Cigarettes per day was most closely related to CO (r = 0.60, P < 0.001) followed by plasma cotinine (r = 0.53, P < 0.001), whereas plasma cotinine was most strongly correlated with CO levels (r = 0.74, P < 0.001), confirming that cotinine is a good indicator of smoking levels; this was not limited by CYP2A6 variants. 3-Hydroxycotinine/cotinine is reported to be a good marker of CYP2A6 activity, and we found that the 3-hydroxycotinine/(cotinine + nicotine) ratio was most correlated with CYP2A6 genotype (r = 0.38, P < 0.001). Inclusion of the CYP2A6*12A allele strengthened the correlation (r = 0.46, P < 0.001), suggesting that the identification of novel alleles will continue to improve this relationship. Nicotine metabolism is slower in smokers, and we have shown that CYP2A6 is reduced by nicotine treatment in monkeys. Here, we found that plasma nicotine levels were inversely correlated with CYP2A6 activity (3-hydroxycotinine/cotinine, r = -0.41, P < 0.001) among those without CYP2A6 variants, suggesting a reduction in metabolism with higher nicotine levels. Together, these findings (a) confirm the use of plasma cotinine and CO as indicators of Caucasians' smoking levels, and that this is not limited by CYP2A6 genetic variation; (b) indicate that 3-hydroxycotinine/cotinine and 3-hydroxycotinine/(cotinine + nicotine) are moderately good indicators of the CYP2A6 genotype; and (c) support that nicotine exposure may reduce its own metabolism. | ||||||||
| 1033 | 35.08 | 11071388 | 2000.11.20 | + | + | Genetic screening of the lipoprotein lipase gene for mutations associated with high triglyceride/low HDL-cholesterol levels. | Hum Genet | |
| H Razzaghi, CE Aston, RF Hamman, MI Kamboh, | ||||||||
| The lipoprotein lipase (LPL) enzyme plays a major role in lipid metabolism, primarily by regulating the catabolism of triglyceride (TG)-rich lipoprotein particles. The gene for LPL is an important candidate for affecting the risk of atherlosclerosis in the general population. Previously, we have shown that the HindIII polymorphism in intron 8 of the LPL gene is associated with plasma TG and HDL-cholesterol variation in Hispanics and non-Hispanic whites (NHWs). However, this polymorphism is located in an intron and hence may be in linkage disequilibrium with a functional mutation in the coding region or intron-exon junctions of the LPL gene. The aim of this study was to initially screen the LPL coding region and the intron-exon junctions by single-strand conformation polymorphism (SSCP) analysis for mutation detection in a group of 86 individuals expressing the phenotype of high TG/low HDL, followed by association studies in a population-based sample of 1,014 Hispanics and NHWs. Four sequence variations were identified by SSCP and DNA sequencing in the coding region of the gene, including two missense mutations (D9N in exon 2 and N291S in exon 6), one samesense mutation (V108V in exon 3), and one nonsense mutation (S447X in exon 9). Multiple regression analyses, including these four mutations and the HindIII polymorphic site, indicate that the association of the HindIII site with plasma TG (P=0.001 in NHWs and P=0.002 in Hispanics) and HDL-cholesterol (P=0.007 in NHWs and P=0.127 in Hispanics) is independent of all other LPL variable sites examined. These observations reinforce the concept that the intronic 8 HindIII site is functional by itself and provide a strong rationale for future comprehensive functional studies to delineate its biological significance. | ||||||||
| 1034 | 35.08 | 11935316 | 2002.05.16 | + | + | A genomic map of a 6-Mb region at 13q21-q22 implicated in cancer development: identification and characterization of candidate genes. | Hum Genet | |
| E Rozenblum, P Vahteristo, T Sandberg, JT Bergthorsson, K Syrjakoski, D Weaver, K Haraldsson, HK Johannsdottir, P Vehmanen, S Nigam, N Golberger, C Robbins, E Pak, A Dutra, E Gillander, DA Stephan, J Bailey-Wilson, SH Juo, T Kainu, A Arason, RB Barkardottir, H Nevanlinna, A Borg, OP Kallioniemi, | ||||||||
| Chromosomal region 13q21-q22 harbors a putative breast cancer susceptibility gene and has been implicated as a common site for somatic deletions in a variety of malignant tumors. We have built a complete physical clone contig for a region between D13S1308 and AFM220YE9 based on 18 yeast artificial chromosome and 81 bacterial artificial chromosome (BAC) clones linked together by 22 genetic markers and 61 other sequence tagged sites. Combining data from 47 sequenced BACs (as of June 2001), we have assembled in silico an integrated 5.7-Mb genomic map with 90% sequence coverage. This area contains eight known genes, two hypothetical proteins, 24 additional Unigene clusters, and approximately 100 predicted genes and exons. We have determined the cDNA and genomic sequence, and tissue expression profiles for the KIAA1008 protein (homologous to the yeast mitotic control protein dis3+), KLF12 (AP-2 repressor), progesterone induced blocking factor 1, zinc finger transcription factor KLF5, and LIM domain only-7, and for the hypothetical proteins FLJ22624 and FLJ21869. Mutation screening of the five known genes in 19 breast cancer families has revealed numerous polymorphisms, but no deleterious mutations. These data provide a basis and resources for further analyses of this chromosomal region in the development of cancer. | ||||||||
| 1035 | 35.08 | 17622941 | 2007.09.19 | + | + | Effect of drug transporter genotypes on pravastatin disposition in European- and African-American participants. | Pharmacogenet Genomics | |
| RH Ho, L Choi, W Lee, G Mayo, UI Schwarz, RG Tirona, DG Bailey, C Michael Stein, RB Kim, | ||||||||
| OBJECTIVE: Our aims were to evaluate the effects of polymorphisms in the hepatic drug uptake transporter organic anion transporting polypeptide 1B1 (OATP1B1, SLCO1B1) and efflux transporters multidrug resistance-associated protein 2 (MRP2, ABCC2), bile salt export pump (BSEP, ABCB11), and breast cancer-related protein (BCRP, ABCG2) on single-dose pravastatin pharmacokinetics in healthy European- and African-American participants. METHODS: The pharmacokinetics of a single oral 40 mg dose of pravastatin was determined in 107 participants (69 European-Americans and 38 African-Americans). Participants were genotyped for known OATP1B1, MRP2, BSEP, and BCRP polymorphisms. Baseline serum total and unconjugated plasma bilirubin concentrations were also determined. RESULTS: OATP1B1 genotypes were ethnicity-dependent with a 521C allele frequency of approximately 15% in European-Americans and approximately 1% in African-Americans. SLCO1B1 521TC genotype was associated with significantly higher pravastatin area under the curve [AUC(0-5)] (P=0.01) and Cmax values (P<0.05). When analyzed by diplotype, SLCO1B1*1a/*15 (N=8) participants exhibited 45 and 80% higher AUC values than SLCO1B1*1a/*1a (N=29) (P=0.013) and SLCO1B1*1b/*1b (N=34) (P=0.001) carriers, respectively. SLCO1B1*15/*15 (N=2) participants exhibited 92 and 149% higher AUC values than SLCO1B1*1a/*1a (P=0.017) and SLCO1B1*1b/*1b (P=0.011) carriers, respectively. European-Americans had significantly higher plasma pravastatin AUC(0-5) (P=0.01) and Cmax values (P=0.009) than African-Americans. Neither ABCC2, ABCB11, nor ABCG2 genotypes were associated with differences in pravastatin pharmacokinetics. We did not observe an effect of SLCO1B1 genotype on baseline total or unconjugated bilirubin levels. CONCLUSION: SLCO1B1 genotype, in particular the 521C allele, had a significant effect on the pharmacokinetics of pravastatin. Even when adjusted for the presence of the SLCO1B1 521C or 388G variant allele, European-Americans demonstrated significantly higher pravastatin AUC and Cmax values than African-Americans. | ||||||||
| 1036 | 35.07 | 12376500 | 2002.12.24 | + | + | XPD codon 751 polymorphism, metabolism genes, smoking, and bladder cancer risk. | Cancer Epidemiol Biomarkers Prev | |
| MC Stern, LR Johnson, DA Bell, JA Taylor, | ||||||||
| Cigarette smoking is the main risk factor for bladder cancer, accounting for at least 50% of bladder cancer in men. Cigarette smoke is a rich source of arylamines, which are detoxified by the NAT2 enzyme and activated by the NAT1 enzyme to highly reactive species that can form bulky adducts on DNA. DNA damage from such adducts is mainly repaired by the nucleotide excision repair pathway, in which the XPD protein functions in opening the DNA helix. We hypothesized that an XPD codon 751 polymorphism (Lys-to-Gln amino acid change) could affect the repair of smoking-induced DNA damage and could be associated with bladder-cancer risk. We also hypothesized that allelic variants of the NAT1 and NAT2 genes might modify the effect of the XPD codon 751 polymorphism on smoking-associated bladder-cancer risk. We determined the XPD codon 751 genotype for 228 bladder-cancer cases and 210 controls who were frequency-matched to cases by age, sex, and ethnicity, and we used our previously published data on the NAT1 and NAT2 genotypes for these same individuals (J. A. Taylor et al., Cancer Res., 58: 3603-3610, 1998). We found a slight decrease in risk for the XPD codon 751 Gln/Gln genotype (adjusted odds ratio: 0.8; 95% confidence interval: 0.4-1.3) compared with subjects with the Lys/Lys or Lys/Gln genotypes. The analysis with smoking showed that smokers with the Lys/Lys or Lys/Gln genotypes were twice as likely to have bladder cancer than smokers with the Gln/Gln genotype (test of interaction P = 0.03). The combined presence of the NAT1/NAT2 high-risk genotype and the XPD Lys/Lys or Lys/Gln genotypes ignoring smoking had an odds ratio that was only slightly higher than expected, assuming no genotype-genotype interaction (P = 0.52). We found little evidence for a gene-gene-exposure, three-way interaction among the XPD codon 751 genotype, smoking, and the NAT1/NAT2 genotype. | ||||||||
| 1037 | 35.06 | 9832193 | 1999.02.10 | + | + | Serotonin transporter gene polymorphisms in patients with unipolar or bipolar depression. | Neurosci Lett | |
| F Bellivier, C Henry, A Szöke, F Schürhoff, M Nosten-Bertrand, J Feingold, JM Launay, M Leboyer, JL Laplanche, | ||||||||
| To explore the involvement of serotonin transporter (5HTT) in mood disorder, we studied two polymorphisms of the 5HTT gene (a variable number of tandem repeats in the second intron (VNTR) and a 44 bp insertion/deletion in the 5HTT linked polymorphic region (5-HTTLPR)) in a sample of unipolar and bipolar patients and controls. Homozygosity for the short variant of the 5-HTTLPR was significantly more frequent in bipolar patients than in controls (chi2 = 4.68, d.f. = 1, P = 0.03) whereas there was no difference between bipolar patients and controls for allele distribution, suggesting a recessive effect. The interaction between the two markers suggests that the two polymorphisms probably have independent effects to determine the susceptibility to affective disorder. Further studies are required to identify the precise phenotype associated with 5HTT polymorphisms in depressed patients. | ||||||||
| 1038 | 35.06 | 15713800 | 2005.07.13 | + | + | Fusion of EML1 to ABL1 in T-cell acute lymphoblastic leukemia with cryptic t(9;14)(q34;q32). | Blood | |
| K De Keersmaecker, C Graux, MD Odero, N Mentens, R Somers, J Maertens, I Wlodarska, P Vandenberghe, A Hagemeijer, P Marynen, J Cools, | ||||||||
| The BCR-ABL1 fusion kinase is frequently associated with chronic myeloid leukemia and B-cell acute lymphoblastic leukemia but is rare in T-cell acute lymphoblastic leukemia (T-ALL). We recently identified NUP214-ABL1 as a variant ABL1 fusion gene in 6% of T-ALL patients. Here we describe the identification of another ABL1 fusion, EML1-ABL1, in a T-ALL patient with a cryptic t(9;14)(q34;q32) associated with deletion of CDKN2A (p16) and expression of TLX1 (HOX11). Echinoderm microtubule-associated protein-like 1-Abelson 1 (EML1-ABL1) is a constitutively phosphorylated tyrosine kinase that transforms Ba/F3 cells to growth factor-independent growth through activation of survival and proliferation pathways, including extracellular signal-related kinase 1/2 (Erk1/2), signal transducers and activators of transcription 5 (Stat5), and Lyn kinase. Deletion of the coiled-coil domain of EML1 abrogated the transforming properties of the fusion kinase. EML1-ABL1 and breakpoint cluster region (BCR)-ABL1 were equally sensitive to the tyrosine kinase inhibitor imatinib. These data further demonstrate the involvement of ABL1 fusions in the pathogenesis of T-ALL and identify EML1-ABL1 as a novel therapeutic target of imatinib. | ||||||||
| 1039 | 35.06 | 14506229 | 2004.01.12 | + | + | G2/M arrest by 1,25-dihydroxyvitamin D3 in ovarian cancer cells mediated through the induction of GADD45 via an exonic enhancer. | J Biol Chem | |
| F Jiang, P Li, AJ Fornace, SV Nicosia, W Bai, | ||||||||
| 1,25-Dihydroxyvitamin D3 suppresses the growth of multiple human cancer cell lines by inhibiting cell cycle progression and inducing cell death. The present study showed that 1,25-dihydroxyvitamin D3 causes cell cycle arrest at the G2/M transition through p53-independent induction of GADD45 in ovarian cancer cells. Detailed analyses have established GADD45 as a primary target gene for 1,25-dihydroxyvitamin D3. A DR3-type vitamin D response element was identified in the fourth exon of GADD45 that forms a complex with the vitamin D receptor.retinoid X receptor heterodimer in electrophoresis mobility shift assays and mediates the dose-dependent induction of luciferase activity by 1,25-dihydroxyvitamin D3 in reporter assays. Chromatin immunoprecipitation assays have shown that the vitamin D receptor is recruited in a ligand-dependent manner to the exonic enhancer but not to the GADD45 promoter regions. In ovarian cancer cells expressing GADD45 antisense cDNA or GADD45-null mouse embryo fibroblasts, 1,25-dihydroxyvitamin D3 failed to induce G2/M arrest. Taken together, these results identify GADD45 as an important mediator for the tumor-suppressing activity of 1,25-dihydroxyvitamin D3 in human ovarian cancer cells. | ||||||||
| 1040 | 35.06 | 15116058 | 2004.05.27 | + | + | The effect of gemfibrozil on the pharmacokinetics of rosuvastatin. | Clin Pharmacol Ther | |
| DW Schneck, BK Birmingham, JA Zalikowski, PD Mitchell, Y Wang, PD Martin, KC Lasseter, CD Brown, AS Windass, A Raza, | ||||||||
| BACKGROUND: Coadministration of statins and gemfibrozil is associated with an increased risk for myopathy, which may be due in part to a pharmacokinetic interaction. Therefore the effect of gemfibrozil on rosuvastatin pharmacokinetics was assessed in healthy volunteers. Rosuvastatin has been shown to be a substrate for the human hepatic uptake transporter organic anion transporter 2 (OATP2). Inhibition of this transporter could increase plasma concentrations of rosuvastatin. The effect of gemfibrozil on rosuvastatin uptake by cells expressing OATP2 was also examined. METHODS: In a randomized, double-blind, 2-period crossover trial, 20 healthy volunteers were given oral doses of gemfibrozil, 600 mg, or placebo twice daily for 7 days. On the fourth morning of each dosing period, a single oral dose of rosuvastatin, 80 mg, was coadministered. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and rosuvastatin-lactone were measured. In addition, the effect of gemfibrozil on the uptake of radiolabeled rosuvastatin by OATP2-transfected Xenopus oocytes was studied. RESULTS: Gemfibrozil increased the rosuvastatin area under the plasma concentration-time curve from time 0 to the time of the last quantifiable concentration [AUC(0-t)] 1.88-fold (90% confidence interval, 1.60-2.21) and the maximum observed rosuvastatin plasma concentration (C(max)) 2.21-fold (90% confidence interval, 1.81-2.69) compared with placebo. N-desmethyl rosuvastatin AUC(0-t) and C(max) decreased by 48% and 39%, respectively. Pharmacokinetics of rosuvastatin-lactone was unchanged. The in vitro results indicate that the maximum gemfibrozil inhibition of rosuvastatin OATP2-mediated uptake was 50%; the inhibition constant for the inhibitory process was 4.0 +/- 1.3 micromol/L. CONCLUSIONS: Gemfibrozil increased rosuvastatin plasma concentrations approximately 2-fold, which is similar to the effect of gemfibrozil on pravastatin, simvastatin acid, and lovastatin acid plasma concentrations and substantially less than the effect observed for cerivastatin. Gemfibrozil inhibition of OATP2-mediated rosuvastatin hepatic uptake may contribute to the mechanism of the drug-drug interaction. Care is warranted when gemfibrozil is coadministered with rosuvastatin and other statins. | ||||||||
| 1041 | 35.06 | 14624403 | 2003.12.12 | + | + | A rapid and simple CYP2D6 genotyping assay--case study with the analgetic tramadol. | Metabolism | |
| J Borlak, R Hermann, K Erb, T Thum, | ||||||||
| There is substantial evidence for a causal relationship between genetic variability of the CYP2D6 gene and changes in the pharmacokinetics of drugs. Therefore, knowledge of single-nucleotide polymorphisms (SNPs) prior to drug administration is highly desired for assisting in the development of individualized pharmacotherapy. We therefore developed a robust assay that detects common CYP2D6 alleles within 60 minutes of blood withdrawal and links carriers of the variant CYP2D6*3 and *4 alleles to the pharmacokinetics of tramadol. This new genotyping assay employs fluorescence resonance energy transfer (FRET) analysis, which permits parallel identification of the CYP2D6*3 and CYP2D6*4 alleles within 60 minutes of blood withdrawal. We determined the genotypes of 100 healthy unrelated individuals and studied the pharmacokinetics of tramadol in 24 CYP2D6 genotyped healthy subjects. The total allelic frequencies of homozygote carriers were 0.015 and 0.25 for the CYP2D6*3 and *4 alleles, respectively, and the plasma area under the curve (AUC) was 84% above those of extensive metabolizers (homozygous EM group): 3,941.2 ng/mL.h (95% confidence interval [CI], 2,928.9 ng/mL.h to 4,953.5 ng/mL.h) versus 2,142.6 ng/mL.h (95% CI, 1,829.6 ng/mL.h to 2,455.7 ng/mL.h). Likewise, the AUC for the O-desmethyl-tramadol metabolite (M1) was significantly reduced in poor metabolizers (PMs): 300.2 ng/mL.h (95% CI, 260.3 ng/mL.h to 340.0 ng/mL.h) versus 842,6 ng/mL.h (95% CI, 715.1 ng/mL.h to 970.0 ng/mL.h). We observed a statistically significant correlation between plasma tramadol AUC and production of the O-desmethyl metabolite in CYP2D6 genotyped healthy volunteers. Our assay can be used reliably in clinical pharmacology studies and may be used for dose adjustment. | ||||||||
| 1042 | 35.05 | 9684917 | 1998.10.22 | + | + | Susceptibility for schizophrenia is not influenced by a functional insertion/deletion variant in the promoter of the serotonin transporter gene. | Eur Arch Psychiatry Clin Neurosci | |
| G Stöber, S Jatzke, A Heils, G Jungkunz, E Fuchs, M Knapp, P Riederer, KP Lesch, | ||||||||
| A possible dysregulation of serotonergic neurotransmission has been implicated in the aetiology of schizophrenic psychoses. In the present study we analysed allelic and genotypic variations of a recently described functional polymorphic region in the promoter of the human serotonin transporter gene (5-HTTLPR) and a variable tandem repeat (VNTR) in intron 2 of the 5-HTT gene. We investigated 413 unrelated individuals, 180 schizophrenic patients and 233 blood donors as controls. With regard to the 5-HTTLPR, both the schizophrenic and the control group did not significantly differ between genotype frequencies (chi2, p = 0.920) and allele frequencies (chi2, p = 0.836). The odds ratio for subjects with schizophrenia who were homozygous for the short allele was 1.04 (95% CI 0.59-1.84). No evidence of allelic association to specific schizophrenia subtypes was found. The 5-HTT associated VNTR also showed no significant differences between either the allelic or the genotypic distributions. Haplotype analysis revealed a significant overall linkage disequilibrium at a level of p = 0.00004. Our findings indicate that both polymorphisms are unlikely to play a substantial role in the genetic predisposition to schizophrenic disorders. | ||||||||
| 1043 | 35.05 | 16788382 | 2006.09.19 | + | + | Four novel defective alleles and comprehensive haplotype analysis of CYP2C9 in Japanese. | Pharmacogenet Genomics | |
| K Maekawa, H Fukushima-Uesaka, M Tohkin, R Hasegawa, H Kajio, N Kuzuya, K Yasuda, M Kawamoto, N Kamatani, K Suzuki, T Yanagawa, Y Saito, J Sawada, | ||||||||
| Genetic variations in cytochrome P450 2C9 (CYP2C9) are known to contribute to interindividual and interethnic variability in response to clinical drugs such as warfarin. In the present study, CYP2C9 from 263 Japanese subjects was resequenced, resulting in the discovery of 62 variations including 32 novel ones. In addition to the two known non-synonymous single nucleotide polymorphisms (SNPs), Ile359Leu (*3; allele frequency=0.030) and Leu90Pro (*13; 0.002), seven novel non-synonymous SNPs, Leu17Ile (0.002), Lys118ArgfsX9 (*25; 0.002), Thr130Arg (*26; 0.002), Arg150Leu (*27; 0.004), Gln214Leu (*28; 0.002), Pro279Thr (*29; 0.002) and Ala477Thr (*30; 0.002), were found. Functional characterization of novel alleles using a mammalian cell expression system in vitro revealed that *25 was a null allele and that *26, *28 and *30 were defective alleles. The *26 product showed a 90% decrease in the Vmax value but little change in the Km value towards diclofenac. Both *28 and *30 products showed two-fold higher Km values and three-fold lower Vmax values than the *1 allele, suggesting the importance of Gln214 and Ala477 for substrate recognition. Linkage disequilibrium and haplotype analyses were performed using the detected variations. Only five haplotypes (frequency >0.02) accounted for most (>87%) of the inferred haplotypes, and they were closely associated with the haplotypes of CYP2C19 in Japanese. Although the haplotype structure of CYP2C9 was rather simple in Japanese, the haplotype distribution was quite different from those previously reported in Caucasians and Africans. Taken together, novel defective alleles and detailed haplotype structures would be useful for determining metabolic phenotypes of CYP2C9 substrate drugs in Japanese and probably Asians. | ||||||||
| 1044 | 35.04 | 12707935 | 2004.02.06 | + | + | Family-based and case-control study of catechol-O-methyltransferase in schizophrenia among Palestinian Arabs. | Am J Med Genet B Neuropsychiatr Genet | |
| I Kremer, M Pinto, I Murad, M Muhaheed, I Bannoura, DJ Muller, TG Schulze, A Reshef, M Blanaru, S Gathas, R Goichman, M Rietschel, M Dobrusin, R Bachner-Melman, L Nemanov, RH Belmaker, W Maier, RP Ebstein, | ||||||||
| COMT is a ubiquitous enzyme crucial to catechol metabolism. The molecular basis of COMT thermolability, that leads to three to fourfold differences in enzyme activity, is due to a substitution of valine with methionine in the Val158/108Met polymorphism. Of special interest is the role of this gene in major psychoses especially since a microdeletion (22q11) containing the COMT gene (velo-cardio-facial syndrome) also carries with it several types of behavioral disorders, including an increased prevalence of schizophrenia. Almost 20 genetic studies have examined the role of COMT in schizophrenia with ambiguous results. Towards clarifying the role of this polymorphism in conferring risk for psychosis, we examined a large group of culturally and ethnically akin Palestinian Arab schizophrenic triads (N = 276) using both a case-control and family-based study. In 194 informative triads with at least one heterozygote parent, no preferential transmission of either COMT allele was observed in this sample (TDT statistic chi-square = 0.14 NS; 131 COMT valine alleles were transmitted and 125 alleles not transmitted). However, using a case-control design a significant increase (Likelihood ratio = 3.935, P = 0.047) in the valine allele was observed in the group of schizophrenic patients (N = 276) compared to an ethnically matched control group (N = 77). The association was stronger in female patients (P = 0.012) similar to other studies showing that some COMT behavioral effects are gender sensitive. In summary, by case-control design but not by a family-based study, there is a weak effect in female patients of the high activity COMT allele in conferring risk for schizophrenia. | ||||||||
| 1045 | 35.04 | 1302038 | 1993.06.10 | + | + | Deficient nifedipine oxidation: a rare inherited trait associated with cystic fibrosis kindreds. | Pharmacogenetics | |
| AK Daly, BS Salh, D Bilton, J Allen, AD Knight, AK Webb, JM Braganza, JR Idle, | ||||||||
| Previous studies have indicated that there is weak genetic linkage between the defective gene in cystic fibrosis (CFTR) and the gene encoding the nifedipine metabolizing enzyme P4503A4 which are both located on chromosome 7. To examine further this possible association, nifedipine metabolism was investigated in a group of 59 volunteers, and 17 adult cystic fibrosis patients and 37 of their relatives. In agreement with the majority of previous studies, the volunteer group showed a unimodal distribution of recoveries for the major metabolite M-II ranging from 33 to 78% excretion in 8 h. In the case of both the cystic fibrosis patients and their parents, the distribution of recoveries was shifted to the left with five out of 20 parents and three out of 11 unrelated cystic fibrosis patients showing recoveries below the range observed in the volunteer group. This poor metabolism appeared to be both reproducible and heritable and did not appear to be a consequence of mutations in the CFTR gene. | ||||||||
| 1046 | 35.04 | 12036916 | 2002.07.16 | + | + | Chemotherapy-induced O(6)-benzylguanine-resistant alkyltransferase mutations in mismatch-deficient colon cancer. | Cancer Res | |
| L Liu, S Schwartz, BM Davis, SL Gerson, | ||||||||
| The ability of O(6)-benzylguanine (BG) to inactivate alkyltransferase (AGT) to potentiate the antitumor efficacy of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) is being tested in clinical trials. As of now, there are no examples of acquired resistance to BG+BCNU in the clinical setting. However, we hypothesized that genetically unstable tumors might develop resistance to the combination after repeated drug-exposures to achieve therapeutic efficacy. To evaluate this possibility, we treated three colon cancer cell lines that are either proficient in mismatch repair (MMR) [SW480 (MMR wild type)] or deficient in MMR [HCT116 (hMLH1 mutant) and HCT15 (hMSH6 mutant)] with three cycles of BG+BCNU. After drug-treatments, HCT116 and HCT15 were completely resistant to BG-potentiated cytotoxicity of BCNU. In these two cell lines, the acquired BG resistance resulted from two de novo and different mutations at amino acid 165 in AGT: 165-lysine (K) to glutamic acid (E) (K165E in HCT116), and 165-lysine to asparagine (N) (K165N in HCT15). Both K165-mutated AGTs had markedly decreased enzymatic activity because of unstable AGT protein but were remarkably resistant to BG inactivation. FISH analysis showed that only one copy of MGMT gene exists in HCT116 cells, and the status of promoter methylation of MGMT in HCT15 showed that one allele of the MGMT promoter has an aberrant methylation. Thus, the MGMT gene expressing AGT either from one copy (HCT116) or from unmethylated allele (HCT15) was mutated because of the exposure to BG+BCNU in these two MMR-deficient cell lines. Conversely, MMR-proficient SW480 cells, treated with three cycles of BG+BCNU, maintained wt AGT and the sensitivity to BG-potentiated BCNU-cytotoxicity. To confirm that K165-mutated AGT proteins were responsible for resistance to BG+BCNU, we transfected K165E and K165N MGMT cDNAs into Chinese hampster ovary (CHO) cells. Transfected CHO cells had low AGT activity but increased IC(50) for either BCNU or temozolomide (TMZ), compared with parental CHO cells. BG did not potentiate the cytotoxicity of these two alkylating agents at concentrations up to 200 microM; in contrast, BG, at 25 microM, sensitized CHO-AGT (transfected with wt MGMT cDNA) cells to BCNU or TMZ-cytotoxicity by 3-4 fold. These results suggest that K165 AGT mutants arising in MMR-deficient tumor cells after treatment with chemotherapeutic agents are both resistant to BG-inactivation and are active in the repair of alkylated DNA adducts. | ||||||||
| 1047 | 35.04 | 10580151 | 2000.01.06 | + | + | Molecular cloning, genomic organization, and identification of the promoter for the human pituitary tumor transforming gene (PTTG). | Gene | |
| SS Kakar, | ||||||||
| Recently, we cloned and sequenced cDNA of a potent pituitary tumor transforming gene (PTTG) from human testis and showed that this gene is expressed highly in various human tumors, including tumors of the pituitary and adrenal glands, and the liver, kidney, endometrium, uterus, and ovary. To determine the genomic organization of the PTTG and its transcriptional regulation in tumors, we isolated the gene. The PTTG spans more than 10kb and contains five exons and four introns. Primer extension and RNA protection assays indicated a transcription start site at an adenine residue at 37 bases upstream of the translation start site (ATG). Analysis of the 5' flanking region of the gene revealed the existence of three SP1/GC boxes, three AP1 and one AP2 binding sequences, a cyclic AMP response element sequence, and an insulin response element sequence. The promoter activity of the PTTG was evaluated by transfecting a human ovarian tumor cell line (SKOV3) and a mouse fibroblast cell line (NIH 3T3) with a chimeric fusion construct containing the 5' flanking sequence (nucleotide from -1336 to +34) and luciferase reporter gene (pluc 1370). The promoter activity of this construct was 210-fold higher in SKOV3 and 20-fold higher in NIH 3T3 cells than the promoterless vector. Deletion of sequences at the 5' end of the pluc 1370 construct from nucleotide -1336 to -1157 (pluc 1190), from nucleotide -1336 to -977 (pluc 1010) and from nucleotide -1336 to -707 (pluc 740) further increased luciferase activity. Further deletion of the 5' sequence from nucleotide -1336 to -407 (pluc 440), and from nucleotide -1336 to -127 (pluc 160) decreased activity by 95%. These results suggest that the sequence from nucleotide -126 to +34 is sufficient for PTTG promoter activity and that the sequence between nucleotide -706 and -407 contains an enhancer element. PTTG promoter activity was eight- to ten-fold higher in SKOV3 cells than NIH 3T3 cells, suggesting a basis for the tumor-specific expression of the PTTG. Knowledge of the genomic organization and the promoter region of the human tumor transforming gene will allow further studies of possible disorders of the PTTG as well as facilitate elucidation of the transcriptional control of PTTG expression in human tumors. | ||||||||
| 1048 | 35.04 | 17010131 | 2006.11.28 | + | + | Association between gene polymorphisms of SLC22A3 and methamphetamine use disorder. | Alcohol Clin Exp Res | |
| N Aoyama, N Takahashi, K Kitaichi, R Ishihara, S Saito, N Maeno, X Ji, K Takagi, Y Sekine, M Iyo, M Harano, T Komiyama, M Yamada, I Sora, H Ujike, N Iwata, T Inada, N Ozaki, | ||||||||
| BACKGROUND: Methamphetamine (MAP) is one of the most frequently used illegal substances in Japan, and family and twin studies have suggested that genetic factors contribute to psychostimulant dependence, including MAP dependence. Organic cation transporter 3 (OCT3) has been reported to be involved in the disposition of MAP as well as MAP-induced behavioral changes in animals. Moreover, SLC22A3 (which encodes OCT3) is a candidate gene for MAP dependence because it is located within a chromosomal region associated with substance dependence. METHODS: Using 96 healthy control subjects, linkage disequilibrium (LD) within the SLC22A3 was investigated, and 5 single-nucleotide polymorphisms (SNPs) were selected as haplotype tag SNPs to search for an association with MAP dependence. Single-marker analyses and haplotype analyses of these SNPs were performed in 213 subjects with MAP dependence and 443 healthy controls. RESULTS: SLC22A3 polymorphisms were not significantly associated with MAP dependence in any of the single-marker and haplotype analyses. When subjects with MAP dependence were divided into polysubstance and single-MAP users, genotype and allele frequency of SNP2 (p=0.024, p=0.011, respectively), allele frequency of SNP3 (p=0.037), and haplotypic frequencies for these 2 SNPs (p=0.0438) differed significantly between groups. CONCLUSIONS: These results suggest that polymorphisms of SLC22A3 are related to the development of polysubstance use in Japanese patients with MAP dependence. | ||||||||
| 1049 | 35.03 | 11678789 | 2001.12.18 | + | + | Genetic polymorphism of cytochrome P450 2C9 in a Caucasian and a black African population. | Br J Clin Pharmacol | |
| MG Scordo, E Aklillu, U Yasar, ML Dahl, E Spina, M Ingelman-Sundberg, | ||||||||
| AIMS: CYP2C9 is a major enzyme in human drug metabolism and the polymorphism observed in the corresponding gene may affect the therapeutic outcome during treatment with several drugs. The distribution of variant CYP2C9 alleles was therefore investigated in an Italian and an Ethiopian population. METHODS: Allele-specific PCR analysis was carried out in order to determine the frequencies of the two most common variant alleles, CYP2C9*2 and CYP2C9*3 in genomic DNA isolated from 157 Italians and 150 Ethiopians. RESULTS: The frequencies of CYP2C9*1 (80%), CYP2C9*2 (11%) and CYP2C9*3 (9%) found in the Italian population were similar to other Caucasian groups. However in the Ethiopian population CYP2C9*1, CYP2C9*2 and CYP2C9*3 were present at a frequency of 94, 4 and 2% respectively. The 95% confidence intervals in CYP2C9*1, CYP2C9*2 and CYP2C9*3 between Italians and Ethiopians were 0.098, 0.176, 0.040, 0.098 and 0.040, 0.098, respectively. CONCLUSIONS: Our results indicate that the Ethiopian population has a unique relative distribution of the CYP2C9 alleles, which is not similar to any other ethnic group hitherto described. | ||||||||
| 1050 | 35.03 | 2721104 | 1989.06.30 | + | + | S-mephenytoin hydroxylation phenotypes in a Swedish population determined after coadministration with debrisoquin. | Clin Pharmacol Ther | |
| EJ Sanz, T Villén, C Alm, L Bertilsson, | ||||||||
| Mephenytoin (100 mg) and debrisoquin (10 mg) were administered orally, both separately and together, to 41 healthy subjects. The ratios between the S and R enantiomers of mephenytoin and between debrisoquin and 4-OH-debrisoquin in urine were determined by use of GC. These ratios were used as measures of drug hydroxylation. There was no change in the phenotypic trait values of the two drugs when they were coadministered. Mephenytoin and debrisoquin then were coadministered to 253 healthy Swedish subjects, before bedtime, and urine samples were collected at periods of 0 to 8, 8 to 24, and 24 to 32 hours after drug administration. In the first sample, seven of the 253 subjects (2.8%, 95% confidence interval 0.8% to 4.8%) had an S/R ratio of greater than 0.8; this indicated that they were poor hydroxylators of S-mephenytoin. In the two consecutive samples, the S/R ratios of mephenytoin did not change in these seven persons, whereas it decreased to less than 0.2 in the third sample in the extensive hydroxylators. As was reported before, there was no relationship between the mephenytoin S/R ratio and the debrisoquin metabolic ratio (rs = 0.01). Coadministration of debrisoquin and mephenytoin before bedtime and urine collection during two consecutive nights allow for an accurate determination of both phenotypes in the population. | ||||||||
| 1051 | 35.03 | 15459958 | 2005.07.29 | + | + | Mutation analysis of NR0B2 among 1545 Danish men identifies a novel c.278G>A (p.G93D) variant with reduced functional activity. | Hum Mutat | |
| SM Echwald, KL Andersen, TI Sørensen, LH Larsen, T Andersen, N Tonooka, H Tomura, J Takeda, O Pedersen, | ||||||||
| Variations of the small heterodimer partner (SHP, NR0B2) gene, an atypical nuclear receptor that inhibits transactivation by hepatocyte nuclear factor (HNF)-4alpha, are associated with obesity among Japanese. The purpose of the study was to evaluate the prevalence of SHP variants among obese Danish men. Using combined SSCP and heteroduplex analysis, we analyzed the entire coding region of SHP for variants in a cohort of 750 Danish men with early-onset obesity and genotyped a cohort of 795 nonobese control subjects using PCR-RFLP. Functional analyses of the identified coding region variants were performed in both MIN6-m9 and HepG2 cell lines. A total of five novel variants, including three missense variants (c.100C>G [p.R34G], c.278G>A [p.G93D], and c.415C>A [p.P139H]) and two silent variants (c.65C>T [p.Y22Y] and c.339G>A [p.P113P]) were identified. Moreover, the previously reported c.512G>C [p.G171A] polymorphism was identified. The 171A allele was not associated with obesity (p = 0.07). The 34G, 93D, and 139H-alleles were rare variants, which were found only among obese subjects. Among the four coding region variants, the 93D-allele showed a reduced in vitro inhibition of the HNF-4alpha transactivation of the HNF-1alpha promoter expression when expressed in MIN6-m9 and HepG2 cell lines (p<0.01). In contrast to reported findings among obese Japanese, functional variants are rare among Danish men. A functional 93D variant of SHP was identified in 1 out of 750 obese and in none of 795 nonobese control subjects. Further large-scale population studies are necessary to assess the clinical impact of this rare variant on obesity risk among European subjects. | ||||||||
| 1052 | 35.02 | 15123731 | 2004.08.11 | + | + | Transcriptional regulation of rat CYP2A3 by nuclear factor 1: identification of a novel NFI-A isoform, and evidence for tissue-selective interaction of NFI with the CYP2A3 promoter in vivo. | J Biol Chem | |
| G Ling, CR Hauer, RM Gronostajski, BT Pentecost, X Ding, | ||||||||
| Rat CYP2A3 and its mouse and human orthologs are expressed preferentially in the olfactory mucosa. We found previously that an element in the proximal promoter region of CYP2A3 (the nasal predominant transcriptional activating (NPTA) element), which is similar to a nuclear factor 1 (NFI)-binding site, is critical for transcriptional activation of CYP2A3 in vitro. We proposed that this element might be important for tissue-selective CYP2A3 expression. The goals of the present study were to characterize NPTA-binding proteins and to obtain more definitive evidence for the role of NFI in the transcriptional activation of CYP2A3. The NPTA-binding proteins were isolated by DNA-affinity purification from rat olfactory mucosa. Mass spectral analysis indicated that isoforms corresponding to all four NFI genes were present in the purified NPTA-binding fraction. Further analysis of NPTA-binding proteins led to the identification of a novel NFI-A isoform, NFI-A-short, which was derived from alternative splicing of the NFI-A transcript. Transient transfection assay showed that NFI-A2, an NFI isoform previously identified in the olfactory mucosa, transactivated the CYP2A3 promoter, whereas NFI-A-short, which lacks the transactivation domain, counteracted the activation. Chromatin immunoprecipitation assays indicated that NFI proteins are associated with the CYP2A3 promoter in vivo, in rat olfactory mucosa, but essentially not in the liver where the CYP2A3 promoter is hypermethylated and CYP2A3 is not expressed. These data strongly support a role for NFI transcription factors in the transcriptional activation of CYP2A3. | ||||||||
| 1053 | 35.01 | 15386366 | 2004.11.30 | + | + | Association of thymidylate synthase polymorphisms with gastric cancer susceptibility. | Int J Cancer | |
| F Graziano, K Kawakami, G Watanabe, A Ruzzo, B Humar, D Santini, V Catalano, R Ficarelli, T Merriman, S Panunzi, E Testa, S Cascinu, I Bearzi, G Tonini, M Magnani, | ||||||||
| We investigated in a case-control study a possible role of thymidylate synthase gene (TS) polymorphisms for gastric cancer susceptibility. Lymphocyte genomic DNA from 134 Italian gastric cancer patients and 139 controls was used for genotyping two polymorphisms in the TS 5'-untranslated region (5'-UTR); a double (2R) or triple (3R) 28-bp repeat and a G/C polymorphism within the triple repeats allele (3G allele). Samples were also genotyped at a 6-bp deletion/insertion (del6 or ins6) polymorphism at position 1494 in the TS 3'-untranslated region (3'-UTR). Unconditional regression with odd ratios (OR) and 95% confidence intervals (CI), haplotype and linkage disequilibrium analyses were used to investigate the association of the polymorphisms with the disease. The global allelic distribution was in Hardy-Weinberg equilibrium. Genotypes with the 3G allele (2R/3G, 3C/3G, 3G/3G) were significantly more frequent in patients than controls and were associated with gastric cancer risk (OR = 2.06; 95% CI = 1.26-3.35). A significant risk was also observed for carriers of the del6 allele in the 3'-UTR. Odds ratios for combined 3G-del6/ins6 and 3G-del6/del6 genotypes were 2.59 (95% CI = 1.36-4.94) and 2.81 (95% CI = 1.22-6.64), respectively. The 3G-del6 haplotype showed a significant association with the disease (p = 0.01). Polymorphisms in the TS gene may contribute to gastric cancer susceptibility and this finding deserve further investigation in the context of novel strategies for gastric cancer prevention. In vitro, 3G genotypes have been related to high TS mRNA expression, which may underlie one of the possible etiologic mechanisms. | ||||||||
| 1054 | 35.01 | 8961271 | 1997.03.20 | + | + | Vitamin D receptors from patients with resistance to 1,25-dihydroxyvitamin D3: point mutations confer reduced transactivation in response to ligand and impaired interaction with the retinoid X receptor heterodimeric partner. | Mol Endocrinol | |
| GK Whitfield, SH Selznick, CA Haussler, JC Hsieh, MA Galligan, PW Jurutka, PD Thompson, SM Lee, JE Zerwekh, MR Haussler, | ||||||||
| Hereditary hypocalcemic vitamin D-resistant rickets is attributable to defects in the nuclear receptor for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. Two novel point mutations (I314S and R391C) identified in the hormone-binding domain of the human vitamin D receptor (VDR) from patients with hereditary hypocalcemic vitamin D-resistant rickets confer the receptor with sharply reduced 1,25-(OH)2D3-dependent transactivation. These natural mutations, especially R391C, also lead to a second specific consequence, namely impaired heterodimeric interaction with retinoid X receptor (RXR). While the transactivation ability of the I314S mutant can be largely restored by providing excess 1,25-(OH)2D3, R391C activity is more effectively restored with exogenous RXR. These observations are reflected also in the clinical course of each patient: the patient bearing the I314S mutation showed a nearly complete cure with pharmacological doses of a vitamin D derivative, whereas the patient bearing R391C responded only partially to such therapy. Further tests with patient fibroblasts and transfected cells show that the activity of the I314S VDR mutant is augmented somewhat by added RXR, while transactivation by the R391C mutant is best corrected by RXR in the presence of excess hormone. Thus, the effects of hormone vs. RXR in bolstering these mutant VDRs, such that they mediate efficient transactivation, are not entirely separable. The unique properties of these genetically altered receptors establish a new subclass of natural human VDR mutants that illustrate, in vivo, the importance of both 1,25-(OH)2D3 binding and heterodimerization with RXR in VDR action. | ||||||||
| 1055 | 35.00 | 11925564 | 2002.05.02 | + | + | Disruption of an SF2/ASF-dependent exonic splicing enhancer in SMN2 causes spinal muscular atrophy in the absence of SMN1. | Nat Genet | |
| L Cartegni, AR Krainer, | ||||||||
| Alteration of correct splicing patterns by disruption of an exonic splicing enhancer may be a frequent mechanism by which point mutations cause genetic diseases. Spinal muscular atrophy results from the lack of functional survival of motor neuron 1 gene (SMN1), even though all affected individuals carry a nearly identical, normal SMN2 gene. SMN2 is only partially active because a translationally silent, single-nucleotide difference in exon 7 causes exon skipping. Using ESE motif-prediction tools, mutational analysis and in vivo and in vitro splicing assays, we show that this single-nucleotide change occurs within a heptamer motif of an exonic splicing enhancer, which in SMN1 is recognized directly by SF2/ASF. The abrogation of the SF2/ASF-dependent ESE is the basis for inefficient inclusion of exon 7 in SMN2, resulting in the spinal muscular atrophy phenotype. | ||||||||
| 1056 | 35.00 | 16424823 | 2006.07.31 | + | + | Genetic susceptibility to tardive dyskinesia among schizophrenia subjects: IV. Role of dopaminergic pathway gene polymorphisms. | Pharmacogenet Genomics | |
| V Srivastava, PG Varma, S Prasad, P Semwal, VL Nimgaonkar, B Lerer, SN Deshpande, T BK, | ||||||||
| OBJECTIVE: Tardive dyskinesia (TD) is an antipsychotic induced side effect observed in 20-30% of schizophrenia subjects on long-term typical antipsychotic treatment. We tested the possible association of 24 polymorphisms from six dopaminergic genes: namely, dopamine receptors D1, D2, D3, D4; the dopamine transporter (DAT); and the catalyzing enzyme catechol-O-methyltransferase (COMT), with TD. METHODS: Multiple SNP/VNTR markers from candidate genes were analyzed using suitable approaches and allelic, genotypic and haplotypic associations were tested. RESULTS: 120 bp duplication marker, 1.2 kb upstream from initiation codon of DRD4 gene showed a significant genotypic association [chi2 = 9.29, P = 0.009; OR (95% CI) = 0.52 (0.31-0.86) for genotype 120 dup/120 dup]. In the COMT gene, a significant allelic [chi2 = 13.87, P = 0.0002] as well as genotypic association [chi2 = 16.08, P = 0.0003; OR (95% CI) = 0.24 (0.11-0.55) for genotype GG] was observed with the 408 C>G (exon 4) single nucleotide polymorphism and a significant genotypic association [chi2 = 6.32, P = 0.04; OR (95% CI) = 0.50 (0.33-0.92) for genotype GG] was observed with 472 G > A (exon 4, Val 158 Met) SNP. 120 bp dup-T-repeat 3 in DRD4 and G-C-A-insC in COMT genes were observed to be TD associated haplotypes. CONCLUSIONS: Our study presents a detailed analysis of the possible role of dopaminergic genes in the genesis of TD. DRD4 and COMT genes were observed to be the most important candidates in North Indian schizophrenia subjects. These suggestive associations need to be investigated in replicate studies. | ||||||||
| 1057 | 34.99 | 15485653 | 2004.12.14 | + | + | A single nucleotide polymorphism in the matrix metalloproteinase-2 promoter is associated with colorectal cancer. | Biochem Biophys Res Commun | |
| E Xu, M Lai, B Lv, X Xing, Q Huang, X Xia, | ||||||||
| Matrix metalloproteinase-2 (MMP-2) is an enzyme with proteolytic activity against matrix proteins, particularly basement membrane constituents. A single nucleotide polymorphism C-->T transition at -1306, which disrupts an Sp1-type promoter site (CCACC box), displayed a strikingly lower promoter activity with T allele. Our study investigated whether the MMP-2 -1306 C-->T polymorphism contributed to the development and progression of colorectal cancer in the Chinese population. One hundred twenty-six colorectal cancer patients and 126 age- and sex-matched controls were included in this study. PCR-based denaturing high performance liquid chromatography analysis and sequencing were used to determine the MMP-2 genotypes. MMP-2 expression of each genotype was analyzed in four colorectal cancer cell lines by semi-quantitative RT-PCR. The correlation between the genotypes and clinicopathological parameters among colorectal cancer cases was investigated. The results showed that the levels of MMP-2 mRNA expression in cell lines containing CC genotype were much higher compared with cell with CT genotype. The frequency of MMP-2 CC genotype was significantly higher in colorectal cancer patients when compared with controls (OR, 1.959; 95% CI, 1.055-3.637). Colorectal cancers with CC genotype were more common with serosa/adventitia layer involvement compared with CT+TT genotypes. Our data suggest that MMP-2 -1306 C-->T polymorphism may be associated with colorectal cancer development and invasion in the Chinese population. | ||||||||
| 1058 | 34.99 | 16385449 | 2006.05.30 | + | + | Strong genetic evidence of DCDC2 as a susceptibility gene for dyslexia. | Am J Hum Genet | |
| J Schumacher, H Anthoni, F Dahdouh, IR König, AM Hillmer, N Kluck, M Manthey, E Plume, A Warnke, H Remschmidt, J Hülsmann, S Cichon, CM Lindgren, P Propping, M Zucchelli, A Ziegler, M Peyrard-Janvid, G Schulte-Körne, MM Nöthen, J Kere, | ||||||||
| We searched for linkage disequilibrium (LD) in 137 triads with dyslexia, using markers that span the most-replicated dyslexia susceptibility region on 6p21-p22, and found association between the disease and markers within the VMP/DCDC2/KAAG1 locus. Detailed refinement of the LD region, involving sequencing and genotyping of additional markers, showed significant association within DCDC2 in single-marker and haplotype analyses. The association appeared to be strongest in severely affected patients. In a second step, the study was extended to include an independent sample of 239 triads with dyslexia, in which the association--in particular, with the severe phenotype of dyslexia--was confirmed. Our expression data showed that DCDC2, which contains a doublecortin homology domain that is possibly involved in cortical neuron migration, is expressed in the fetal and adult CNS, which--together with the hypothesized protein function--is in accordance with findings in dyslexic patients with abnormal neuronal migration and maturation. | ||||||||
| 1059 | 34.98 | 7781266 | 1995.07.20 | + | + | The hydroxylation of omeprazole correlates with S-mephenytoin metabolism: a population study. | Clin Pharmacol Ther | |
| JD Balian, N Sukhova, JW Harris, J Hewett, L Pickle, JA Goldstein, RL Woosley, DA Flockhart, | ||||||||
| We compared omeprazole and mephenytoin as probes for the CYP2C19 metabolic polymorphism. Single oral doses of omeprazole (20 mg) or mephenytoin (100 mg) were administered at least 1 week apart to 167 healthy volunteers. Mephenytoin metabolism was measured using the amount of 4'-hydroxymephenytoin and the S/R ratio of mephenytoin in an 8-hour urine collection. Omeprazole hydroxylation was measured using the ratio of omeprazole to 5'-hydroxyomeprazole in serum 2 hours after dosing. All three methods separated poor- or extensive-metabolizer phenotypes with complete concordance. Omeprazole hydroxylation correlated with the S/R ratio of mephenytoin in extensive metabolizers (r2 = 0.681; p < 0.001). Genotyping tests showed that six poor metabolizers of omeprazole were homozygous for a single base pair mutation in exon 5 of CYP2C19. These results support the hypothesis that omeprazole 5'-hydroxylation cosegregates with the CYP2C19 metabolic polymorphism. | ||||||||
| 1060 | 34.97 | 16044105 | 2006.04.25 | + | + | Metabolic ratios of psychotropics as indication of cytochrome P450 2D6/2C19 genotype. | Ther Drug Monit | |
| J van der Weide, EH van Baalen-Benedek, JE Kootstra-Ros, | ||||||||
| The cytochrome P450 enzymes (CYP) 2C19 and 2D6 are involved in the metabolism of many psychotropic drugs. Variability in enzyme activity results in variable metabolic capacities, affecting the metabolism of substrates. The metabolic ratio (MR) of drugs metabolized via these enzymes may therefore reflect the enzyme's activity and/or genotype. To serve as an example for different groups of medications, the selective serotonin reuptake inhibitor venlafaxine, the tricyclic antidepressant amitriptyline, and the antipsychotic risperidone were studied to examine a possible correlation between the MRs of these drugs and the CYP2C19 and/or CYP2D6 genotype. For this purpose data from routine genotyping and serum level analysis were used. The relationships between the observed metabolic ratios and CYP2D6 and/or CYP2C19 genotype were characterized using nonparametric statistical analysis. A clear correlation was observed between the CYP2D6 genotype and the metabolic ratio of venlafaxine. Genotyping of individuals with a log(MR) < -0.6 or a log(MR) > 0.2 would include all patients with an aberrant genotype but would result in a reduction of 52% of genotyping reactions. Slow metabolism of amitriptyline is correlated with a log(MR) > 0.4. Genotyping only those subjects with a log(MR) > 0.4 would result in 88% fewer genotyping reactions. For risperidone, genotyping individuals with a log(MR) > 0.4 would include all CYP2D6 poor metabolizers while reducing the number of genotyping reactions by 93%. According to these data, correlations exist between the log(MR) of venlafaxine, amitriptyline, and risperidone and the genotype of the CYP enzymes involved in their metabolism. From the ranges of log(MR) defined here, a high percentage of aberrant metabolizers can be detected even when patients are not routinely genotyped. Thus, the metabolic ratio may serve as an indication of when genotyping should be considered. | ||||||||
| 1061 | 34.97 | 12065557 | 2002.07.08 | + | + | Patient-tailored antiemetic treatment with 5-hydroxytryptamine type 3 receptor antagonists according to cytochrome P-450 2D6 genotypes. | J Clin Oncol | |
| R Kaiser, O Sezer, A Papies, S Bauer, C Schelenz, PB Tremblay, K Possinger, I Roots, J Brockmöller, | ||||||||
| PURPOSE: The use of serotonin 5-hydroxytryptamine type 3 receptor antagonists has substantially reduced, but not eliminated, nausea and vomiting in cancer chemotherapy. This study sought to investigate whether efficacy of antiemetic treatment with ondansetron and tropisetron depends on cytochrome P-450 2D6 (CYP2D6) genotype, hypothesizing that the rapid and particularly the ultrarapid metabolizers of these drugs are at risk of being undertreated. PATIENTS AND METHODS: Included in the study were 270 cancer patients receiving their first day of chemotherapy. Nausea and vomiting were documented using standardized interviews. The intensity of nausea was measured with visual analog scales before and twice during the chemotherapy. The relationship between the CYP2D6 genotypes and the tropisetron serum concentrations 3 and 6 hours after drug administration was analyzed in a subgroup of 42 patients. CYP2D6 genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: Genetically defined poor metabolizers had higher serum concentrations of tropisetron than all other patients (P <.03). Approximately 30% of all patients receiving chemotherapy experienced nausea and vomiting. Genetically defined ultrarapid meta-bolizers of CYP2D6 substrates had higher frequency of vomiting within the first 4 hours (P <.001) and within the period 5 to 24 hours (P <.03) after treatment than all the other patients; the tendency for nausea was similar. This difference was more pronounced in patients treated with tropisetron than in those treated with ondansetron. CONCLUSION: Antiemetic treatment with tropisetron or ondansetron could be improved by adjustment for the CYP2D6 genotype; approximately 50 subjects would have to be genotyped to protect one patient from severe emesis. | ||||||||
| 1062 | 34.96 | 16636344 | 2006.06.07 | + | + | Comprehensive analysis of UGT1A polymorphisms predictive for pharmacokinetics and treatment outcome in patients with non-small-cell lung cancer treated with irinotecan and cisplatin. | J Clin Oncol | |
| JY Han, HS Lim, ES Shin, YK Yoo, YH Park, JE Lee, IJ Jang, DH Lee, JS Lee, | ||||||||
| PURPOSE: To determine whether uridine diphosphate-glucuronosyltransferase 1A1, UGT1A7, and UGT1A9 polymorphisms affect the pharmacokinetics (PK) of irinotecan and treatment outcome of Korean patients with advanced non-small-cell lung cancer (NSCLC). METHODS: Eighty-one patients with advanced NSCLC were treated with irinotecan (80 mg/m2) on day 1 and 8 and cisplatin (60 mg/m2) on day 1 intravenously of each 3-week cycle. Genomic DNA was extracted from peripheral blood and genotyped using direct sequencing. We analyzed the association of UGT1A genotypes with irinotecan PK and clinical outcomes. All statistical tests were two-sided. RESULTS: In genotype-PK association analysis, UGT1A1*6/*6 (n = 6), UGT1A7*3/*3 (n = 6), and UGT1A9-118(dT)9/9 (n = 11) were associated with significantly lower area under the time-concentration curve (AUC) SN-38G to SN-38 (AUC(SN-38G)/AUC(SN-38)) ratio (P = .002, P = .009, and P = .001, respectively). In linkage disequilibrium analysis, the UGT1A7 variants were highly linked with the UGT1A1*6 (D' = 0.85, r2 = 0.63) and UGT1A9*22 (D' = 0.95, r2 = 0.88), which was substantiated in haplotype analysis. Patients with UGT1A1*6/*6 had lower tumor response and higher incidence of severe neutropenia. UGT1A9-118(dT)9/9 also showed a trend for high incidence of severe diarrhea, but not tumor response. In survival analysis, patients with UGT1A1*6/*6 had significantly shorter progression-free survival (P = .001) and overall survival (P = .017). CONCLUSION: These findings suggest that UGT1A1*6 and UGT1A9*22 genotypes may be important for SN-38 glucuronidation and associate with irinotecan-related severe toxicity. Specifically, UGT1A1*6 might be useful for predicting tumor response and survival outcome of Korean patients with NSCLC treated with irinotecan-based chemotherapy. | ||||||||
| 1063 | 34.94 | 14605873 | 2004.03.16 | + | + | Analysis of heat-shock protein 70 gene polymorphisms and the risk of Parkinson's disease. | Hum Genet | |
| YR Wu, CK Wang, CM Chen, Y Hsu, SJ Lin, YY Lin, HC Fung, KH Chang, GJ Lee-Chen, | ||||||||
| Parkinson's disease (PD) involves several genetic and environmental components. Heat-shock protein 70, a chaperone that is up-regulated in stress responses and that refolds protein, may be involved in the pathogenesis of PD. We have investigated the association of polymorphisms -110 A/C, +190 G/C, +1267 A/G, +2074 G/C, and +2437 G/C in the 5' and coding regions of the HSP70-1, HSP70-2, and HSP70-hom genes with the risk of PD by screening DNA samples from 274 PD patients and 183 controls in assays based on the polymerase chain reaction. There was no statistically significant difference in genotype distribution between patients and controls for the three coding-region polymorphisms in HSP70-2 and HSP70-hom. However, for HSP70-1, the overall genotype distribution was significantly different at the -110 site (P=0.004) and tended to be different at the +190 site (P=0.012) between patients and controls. The frequencies of the -110 CC and +190 CC genotypes were significantly higher in PD patients than in controls (P=0.001 and 0.006, respectively). Both -110 CC (odds ratio: 2.91; 95% CI: 1.51-5.96; P=0.002) and +190 CC (odds ratio: 3.59; 95% CI: 1.53-9.88; P=0.006) genotypes were significantly associated with PD. Reporter constructs containing the -110 A allele cloned into a luciferase reporter plasmid drove marginally higher transcriptional activity of HSP70-1 compared with the -110 C allele in both control and heat-shocked IMR32 and 293 cells. Therefore, -110 A/C may be a functional polymorphism in the 5' promoter region of HSP70-1 and may affect susceptibility to PD. | ||||||||
| 1064 | 34.93 | 16815313 | 2006.08.03 | + | + | VKORC1 and CYP2C9 genotypes and acenocoumarol anticoagulation status: interaction between both genotypes affects overanticoagulation. | Clin Pharmacol Ther | |
| T Schalekamp, BP Brassé, JF Roijers, Y Chahid, JH van Geest-Daalderop, H de Vries-Goldschmeding, EM van Wijk, AC Egberts, A de Boer, | ||||||||
| OBJECTIVE: Our objective was to assess the effects of VKORC1 and CYP2C9 genotypes on severe overanticoagulation and time to achieve stability and their contributions to dose requirement during the initial phase of acenocoumarol treatment. METHODS: A prospective follow-up study was conducted at 2 anticoagulation clinics in The Netherlands. We assessed the CYP2C9 genotype (CYP2C9*2 and CYP2C9*3 polymorphisms) and the VKORC1 C1173T genotype of the subjects and collected data on international normalized ratio, dose, comedication, and comorbidity. RESULTS: Of the 231 patients in the cohort, 150 (64.9%) had a VKORC1 C1173T polymorphism and 84 (36.4%) had a CYP2C9*2 or CYP2C9*3 allele. Only carriers of a combination of a CYP2C9 polymorphism and a VKORC1 polymorphism had an increased risk of severe overanticoagulation compared with subjects with no polymorphism or only 1 polymorphism (hazard ratio, 3.83 [95% confidence interval, 1.62-9.05]). The time to achieve stability was associated with the possession of the CYP2C9 genotype, not with the VKORC1 genotype (hazard ratio for CYP2C9*3 allele compared with CYP2C9 wild type, 0.59 [95% confidence interval, 0.40-0.87]). Patients with a VKORC1 polymorphism required significantly lower doses than VKORC1 CC wild-type patients. A larger part of the variability in dose requirement was explained by the VKORC1 genotype than by the CYP2C9 genotype (21.4% and 4.9%, respectively). CONCLUSION: Being a carrier of a combination of polymorphisms of VKORC1 and CYP2C9, rather than of one of these polymorphisms, is associated with severe overanticoagulation. The time to achieve stability is mainly associated with the CYP2C9 genotype. | ||||||||
| 1065 | 34.91 | 15354335 | 2005.02.23 | + | Single-nucleotide polymorphisms in SCN5A gene in Chinese Han population and their correlation with cardiac arrhythmias. | Genet Med | ||
| J Chen, X Xie, J Zhu, Q Tao, X Wang, | ||||||||
| 1066 | 34.91 | 16220109 | 2006.01.04 | + | + | Genotype-phenotype correlation between the polymorphic UGT2B17 gene deletion and NNAL glucuronidation activities in human liver microsomes. | Pharmacogenet Genomics | |
| P Lazarus, Y Zheng, E Aaron Runkle, JE Muscat, D Wiener, | ||||||||
| The nicotine-derived tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is one of the most potent and abundant procarcinogens found in tobacco and tobacco smoke, and glucuronidation of its major metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), is an important mechanism for NNK detoxification. In cigarette smokers and tobacco chewers, there is a wide variation in the urinary levels of the ratio of NNAL to NNAL glucuronide (NNAL-Gluc). To determine whether genetic variation plays a potential role in this inter-individual variability, NNAL-glucuronidating activities were analysed in a series of human liver microsomal specimens and compared with UGT2B17 deletion genotypes in the same subjects. Assays performed in vitro demonstrated that over-expressed UGT2B17 exhibits high O-glucuronidating activity against NNAL. When stratifying subjects by UGT2B17 genotype, a significant or near-significant decrease in NNAL-O-Gluc formation was observed in liver microsomes from individuals who were either heterozygous [(+/0), P=0.07] or homozygous [(0/0), P=0.016] for the UGT2B17 deletion compared to liver microsomes from individuals with intact UGT2B17 alleles [(+/+)]. There was a significant (P<0.01) association between the level of liver microsomal NNAL-O-glucuronide formation and increasing numbers of the UGT2B17 null alleles in the liver microsomal specimens examined in this study, and a significant decrease in NNAL-O-Gluc formation was observed when comparing liver microsomes from individuals who had at least one UGT2B17 allele deleted [(+/0)+(0/0)] versus microsomes from UGT2B17 (+/+) subjects (P=0.004). When stratifying by the median value of NNAL-O-Gluc formation activity, a significantly (P=0.015) higher number of subjects with liver microsomes having low NNAL-O-Gluc formation activity contained the UGT2B17 null genotype compared to subjects with liver microsomes exhibiting high NNAL-O-Gluc formation activity. When stratifying by UGT2B7/UGT2B17 haplotypes, the association between the level of liver microsomal NNAL-O-glucuronide formation and increasing numbers of the UGT2B17 null allele was at the level of statistical significance for subjects with the UGT2B7 (*1/*2) (P=0.05) or UGT2B7 (*2/*2) (P<0.02) genotypes. These data suggest that the UGT2B17 deletion polymorphism is associated with a reduced rate of NNAL detoxification in vivo and may increase individual susceptibility to tobacco-related cancers. | ||||||||
| 1067 | 34.89 | 17377957 | 2007.06.28 | + | + | Influence of rabeprazole and lansoprazole on the pharmacokinetics of tacrolimus in relation to CYP2C19, CYP3A5 and MDR1 polymorphisms in renal transplant recipients. | Biopharm Drug Dispos | |
| M Miura, K Inoue, H Kagaya, S Satoh, H Tada, Y Sagae, T Habuchi, T Suzuki, | ||||||||
| The objective of this study was to evaluate whether genetic polymorphisms of CYP2C19, CYP3A5 and MDR1 significantly impact the interaction between tacrolimus and rabeprazole or lansoprazole. Seventy-three recipients were randomly assigned after renal transplantation to receive repeated doses of tacrolimus for 28 days with a regimen of either 20 mg of rabeprazole or 30 mg of lansoprazole. Blood concentrations of tacrolimus were measured by microparticle enzyme immunoassay. The mean daily dose and the dose-adjusted area under the plasma concentration-time curves from 0 to 12 h (AUC(0-12)) of tacrolimus coadministered with rabeprazole or lansoprazole were the lowest and highest, respectively, in CYP2C19 poor metabolizers (PMs) having the CYP3A5*3/*3 genotype (0.084 and 0.112 mg/kg/day and 1.269 and 1.033 ng.h/ml/mg/kg, respectively). On the other hand, the mean dose-adjusted AUC(0-12) of tacrolimus coadministered with rabeprazole or lansoprazole were the highest in CYP2C19 PMs having the MDR13435CC+CT genotype, but not significantly.The present study indicates that there are significant interactions between tacrolimus and rabeprazole or lansoprazole in CYP2C19 PM renal transplant recipients bearing the CYP3A5*3/*3 genotypes. For recipients having these genetic polymorphisms, lower dosages of tacrolimus are required to achieve the target therapeutic index. | ||||||||
| 1068 | 34.89 | 16777480 | 2006.12.01 | + | + | Determinants of chemosensitivity in gastric cancer. | Curr Opin Pharmacol | |
| DJ Park, HJ Lenz, | ||||||||
| Recent advances in the management of gastric cancer, especially in the arena of chemotherapy, are paving the way for optimization of treatment that maximizes effectiveness while minimizing toxicity. The expansion of the chemotherapeutic armamentarium has led to multiple combinations of cytotoxic agents. Unfortunately, the benefit of chemotherapy has been modest at best, and no one combination has shown significant superiority over the others in comparative Phase III trials. It is in this setting that pharmacogenetic advances have the potential to play an important role in achieving superior clinical outcome among different subsets of patients through prospective prediction of clinical benefit to particular regimens. We are just beginning to make inroads in gastric cancer pharmacogenetics, mostly through small, pilot retrospective studies. Several potential candidates, such as thymidylate synthase, excision repair complementation group 1 and glutahione S-transferase P1, have been identified so far and more are bound to surface, especially when biologic therapies are added to the armamentarium. Serious challenges lay ahead given the complex nature of cytotoxic metabolism with multiple players working together to influence drug effectiveness and/or toxicity. Well-designed large prospective trials are needed to identify key genes among the multiple potential candidates that can help a clinician make real-time treatment decisions in respect to a particular regimen depending on a patient's pharmacogenetic profile. | ||||||||
| 1069 | 34.89 | 9067278 | 1997.04.09 | + | + | Methylenetetrahydrofolate reductase polymorphism, dietary interactions, and risk of colorectal cancer. | Cancer Res | |
| J Ma, MJ Stampfer, E Giovannucci, C Artigas, DJ Hunter, C Fuchs, WC Willett, J Selhub, CH Hennekens, R Rozen, | ||||||||
| Folate derivatives are important in experimental colorectal carcinogenesis; low folate intake, particularly with substantial alcohol intake, is associated with increased risk. The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate, required for purine and thymidine syntheses, to 5-methyltetrahydrofolate, the primary circulatory form of folate necessary for methionine synthesis. A common mutation (677C-->T) in MTHFR reduces enzyme activity, leading to lower levels of 5-methyltetrahydrofolate. To evaluate the role of folate metabolism in human carcinogenesis, we examined the associations of MTHFR mutation, plasma folate levels, and their interaction with risk of colon cancer. We also examined the interaction between genotype and alcohol intake. We used a nested case-control design within the Physicians' Health Study. Participants were ages 40-84 at baseline when alcohol intake was ascertained and blood samples were drawn. During 12 years of follow-up, we identified 202 colorectal cancer cases and matched them to 326 cancer-free controls by age and smoking status. We genotyped for the MTHFR polymorphism and measured plasma folate levels. Men with the homozygous mutation (15% in controls) had half the risk of colorectal cancer [odds ratio (OR), 0.49; 95% confidence interval (CI), 0.27-0.87] compared with the homozygous normal or heterozygous genotypes. Overall, we observed a marginal significant increased risk of colorectal cancer (OR, 1.78; 95% CI, 0.93-3.42) among those whose plasma folate levels indicated deficiency (<3 ng/ml) compared with men with adequate folate levels. Among men with adequate folate levels, we observed a 3-fold decrease in risk (OR, 0.32; 95% CI, 0.15-0.68) among men with the homozygous mutation compared with those with the homozygous normal or heterozygous genotypes. However, the protection due to the mutation was absent in men with folate deficiency. In men with the homozygous normal genotype who drank little or no alcohol as reference, those with the homozygous mutation who drank little or no alcohol had an 8-fold decrease in risk (OR, 0.12; 95% CI, 0.03-0.57), and for moderate drinkers, a 2-fold decrease in risk (OR, 0.42; 95% CI, 0.15-1.20); no decrease in risk was seen in those drinking 1 or more drinks/day. Our findings provide support for an important role of folate metabolism in colon carcinogenesis. In particular, these results suggest that the 677C-->IT mutation in MTHFR reduces colon cancer risk, perhaps by increasing 5,10-methylenetetrahydrofolate levels for DNA synthesis, but that low folate intake or high alcohol consumption may negate some of the protective effect. | ||||||||
| 1070 | 34.89 | 15045499 | 2004.12.17 | + | + | Cytochrome P450 2C9 phenotyping using low-dose tolbutamide. | Eur J Clin Pharmacol | |
| A Jetter, M Kinzig-Schippers, A Skott, A Lazar, D Tomalik-Scharte, J Kirchheiner, M Walchner-Bonjean, U Hering, V Jakob, M Rodamer, W Jabrane, D Kasel, J Brockmöller, U Fuhr, F Sörgel, | ||||||||
| OBJECTIVES: The hypoglycaemic drug tolbutamide is used for assessment of CYP2C9 activity in vivo. However, therapeutically active doses of 500 mg bear the risk of hypoglycaemia, and a tolbutamide-derived parameter based on a single plasma or urine concentration reflecting CYP2C9 activity accurately is lacking. METHODS: We examined tolbutamide and its metabolites 4'-hydroxy-tolbutamide and carboxytolbutamide in plasma and urine of 26 healthy, male volunteers up to 24 h after intake of 125 mg tolbutamide using liquid chromatography-tandem mass spectrometry. CYP2C9 genotypes were determined by sequencing of exons 3 and 7. Raw plasma and urine data were compared with pharmacokinetic parameters, CYP2C9 genotypes, and data from a study in 23 volunteers with all six CYP2C9*1-*3 combinations who received 500 mg tolbutamide. RESULTS: Plasma clearance and tolbutamide plasma concentrations 24 h after drug intake reflected the genotypes: 0.85 l/h and 1.70 microg/ml (95% confidence interval, CI, 0.80-0.89 l/h and 1.50-1.90 microg/ml) for CYP2C9*1 homozygotes (n=15), 0.77 l/h and 2.14 microg/ml (95%CI, 0.67-0.88 l/h and 1.64-2.63 microg/ml) for *1/*2 genotypes (n=7), 0.60 l/h and 3.13 microg/ml (95%CI, 0.58-0.62 l/h and 2.68-3.58 microg/ml) for *1/*3 genotypes (n=3), and 0.57 l/h and 3.27 microg/ml in the single *2/*2 carrier. Natural logarithms of tolbutamide plasma concentrations 24 h after intake correlated to plasma clearance (r(2)=0.84, P<0.0000001). This correlation was confirmed in the comparison data set (r(2)=0.97, P<0.0000001). CONCLUSIONS: A low dose of 125 mg tolbutamide can safely and accurately be used for CYP2C9 phenotyping. As a simple metric for CYP2C9 activity, we propose to determine tolbutamide in plasma 24 h after drug intake. | ||||||||
| 1071 | 34.89 | 11186131 | 2001.04.26 | + | + | Structural characterization of a new variant of the CYP2A6 gene (CYP2A6*1B) apparently diagnosed as heterozygotes of CYP2A6*1A and CYP2A6*4C. | Pharmacogenetics | |
| N Ariyoshi, Y Takahashi, M Miyamoto, Y Umetsu, S Daigo, T Tateishi, S Kobayashi, Y Mizorogi, MA Loriot, I Stücker, P Beaune, M Kinoshita, T Kamataki, | ||||||||
| During the course of investigating the frequency of a CYP2A6 whole deletion-type polymorphism (CYP2A6*4C) in Japanese, an unexpectedly large population of heterozygotes for CYP2A6*4C and the wild-type (CYP2A6*1A) was found. Cloning of a cDNA encoding CYP2A6 from the liver of individuals judged as heterozygotes for CYP2A6*4C and the CYP2A6*1A was carried out to identify the causal allele(s) responsible for a possible overestimation. A clone isolated from the liver cDNA library possessed 58 bp sequences in the 3'-untranslated region, which was replaced with the corresponding region of the CYP2A7 gene. The same gene conversion existed in the genomic DNA, indicating that the replacement was not a cloning artifact. Based on the gene structure of the allele (CYP2A6*1B), this variant was thought to be one of the causal alleles responsible for overestimation of heterozygotes for CYP2A6*4C and CYP2A6* A. To investigate this further, we developed a genotyping method which could distinguish the CYP2A6*A, CYP2A6*1B and CYP2A6*4C alleles from each other. The results clearly showed that CYP2A6*1B was the sole allele responsible for the overestimation. We conclude that the new genotyping method allows determination of six genotypes of the CYP2A6 gene, simultaneously and precisely, in both Oriental and Caucasian populations. | ||||||||
| 1072 | 34.89 | 14581470 | 2004.02.10 | + | + | Tumor necrosis factor-alpha inhibits endothelial nitric-oxide synthase gene promoter activity in bovine aortic endothelial cells. | J Biol Chem | |
| HD Anderson, D Rahmutula, DG Gardner, | ||||||||
| Tumor necrosis factor-alpha (TNF-alpha) has been shown to reduce endothelial nitric-oxide synthase (eNOS) gene expression through post-transcriptional regulation of mRNA stability. The current study documented an independent effect of the cytokine on the eNOS gene promoter. TNF-alpha effected a time- and dose-dependent reduction in activity of a transiently transfected human -1197 eNOS-luciferase reporter. This reduction was inhibited by co-transfection of dominant negative IKKbeta as well as a nonphosphorylatable constitutively suppressive mutant of IkappaB implying involvement of the NFkappaB cascade in the inhibitory effect. The locus of the TNF-alpha-dependent inhibition was traced to two Sp1-binding sites positioned between -109 and -95 and -81 and -67 relative to the transcription start site. Electrophoretic mobility shift analysis and immunoperturbation studies showed evidence for Sp1 and Sp3 binding to each element. TNF-alpha treatment had no effect on the binding pattern to the downstream (-81 to -67) site but did suppress association of Sp1 and Sp3 to the upstream (-109 to -95) site. Collectively, these data indicate that TNF-alpha exerts transcriptional, as well as post-transcriptional, effects on eNOS gene expression and suggest a potential mechanism to account for the endothelial dysfunction that accompanies disorders such as diabetes mellitus and heart failure. | ||||||||
| 1073 | 34.89 | 10969800 | 2000.09.14 | + | + | The frequency of germ-line mutations in the breast cancer predisposition genes BRCA1 and BRCA2 in familial prostate cancer. The Cancer Research Campaign/British Prostate Group United Kingdom Familial Prostate Cancer Study Collaborators. | Cancer Res | |
| SA Gayther, KA de Foy, P Harrington, P Pharoah, WD Dunsmuir, SM Edwards, C Gillett, A Ardern-Jones, DP Dearnaley, DF Easton, D Ford, RJ Shearer, RS Kirby, AL Dowe, J Kelly, MR Stratton, BA Ponder, D Barnes, RA Eeles, | ||||||||
| Predisposition to prostate cancer has a genetic component, and there are reports of familial clustering of breast and prostate cancer. Two highly penetrant genes that predispose individuals to breast cancer (BRCA1 and BRCA2) are known to confer an increased risk of prostate cancer of about 3-fold and 7-fold, respectively, in breast cancer families. Blood DNA from affected individuals in 38 prostate cancer clusters was analyzed for germ-line mutations in BRCA1 and BRCA2 to assess the contribution of each of these genes to familial prostate cancer. Seventeen DNA samples were each from an affected individual in families with three or more cases of prostate cancer at any age; 20 samples were from one of affected sibling pairs where one was < or = 67 years at diagnosis. No germ-line mutations were found in BRCA1. Two germ-line mutations in BRCA2 were found, and both were seen in individuals whose age at diagnosis was very young (< or = 56 years) and who were members of an affected sibling pair. One is a 4-bp deletion at base 6710 (exon 11) in a man who had prostate cancer at 54 years, and the other is a 2-bp deletion at base 5531 (exon 11) in a man who had prostate cancer at 56 years. In both cases, the wild-type allele was lost in the patient's prostate tumor at the BRCA2 locus. However, intriguingly, in neither case did the affected brother also carry the mutation. Germ-line mutations in BRCA2 may therefore account for about 5% of prostate cancer in familial clusters. | ||||||||
| 1074 | 34.88 | 16952492 | 2006.10.05 | + | + | Validation of incorporating flurbiprofen into the Pittsburgh cocktail. | Clin Pharmacol Ther | |
| NK Zgheib, RF Frye, TS Tracy, M Romkes, RA Branch, | ||||||||
| BACKGROUND: We have previously shown that flurbiprofen metabolism to 4'-hydroxyflurbiprofen provides an in vivo measure of cytochrome P450 (CYP) 2C9 activity. This study evaluated the possibility of incorporating flurbiprofen into the current 5-drug Pittsburgh cocktail. METHODS: In a randomized, 3-way, Latin-square, crossover-design study, 24 healthy subjects (mean age [+/-SD], 47.8 +/- 15.1 years) received flurbiprofen (50 mg) and the Pittsburgh 5-drug cocktail (100 mg caffeine, 100 mg mephenytoin, 10 mg debrisoquin [INN, debrisoquine], 250 mg chlorzoxazone, and 100 mg dapsone) separately and in combination on 3 occasions over a period of 5 weeks. Urine was collected from 0 to 8 hours, and plasma was obtained at 4 and 8 hours after drug administration. Parent drug and metabolite concentrations were measured to determine phenotypic indices for each of the metabolizing enzymes. RESULTS: The geometric mean ratio and 90% confidence interval of the phenotypic indices were included within the 80% to 125% bioequivalence range for each of the probe drugs. There were no statistically significant differences between the phenotypic indices determined after administration of the 5-drug and 6-drug cocktails. However, there was a small but statistically significant increase (7.5%, P = .03) in the 8-hour urinary flurbiprofen recovery ratio after administration of the 6-drug cocktail compared with that after administration of flurbiprofen alone. The 6-drug cocktail was well tolerated. CONCLUSION: The results of this study show that caffeine (CYP1A2), chlorzoxazone (CYP2E1), dapsone (N-acetyltransferase 2), debrisoquin (CYP2D6), flurbiprofen (CYP2C9), and mephenytoin (CYP2C19) can be simultaneously administered in low doses without metabolic interaction. | ||||||||
| 1075 | 34.87 | 17286792 | 2007.04.17 | + | + | Genetic polymorphisms in MDR1 and CYP3A5 and MDR1 haplotype in mainland Chinese Han, Uygur and Kazakh ethnic groups. | J Clin Pharm Ther | |
| D Li, GL Zhang, YQ Lou, Q Li, X Wang, XY Bu, | ||||||||
| BACKGROUND AND OBJECTIVE: The drug transporter MDR1 and the drug metabolizing enzyme CYP3A are the two major biological factors determining the pharmacokinetics of many drugs. The functional MDR1 single nucleotide polymorphisms (SNPs) and a prevalent CYP3A5 SNP show marked interethnic variation among Orientals, Caucasians and Africans. In this study, we investigated the distribution of MDR1 and CYP3A5 SNPs among mainland Chinese Han, Uygur and Kazakh ethnic groups. METHODS: Genotypes of the MDR1 C1236T, G2677T/A and C3435T, and CYP3A5*3, CYP3AP1*3 SNPs were determined in 434 unrelated healthy subjects (165 Chinese Han, 161 Chinese Uygur and 108 Chinese Kazakh) using polymerase chain reaction followed by restriction fragment length polymorphism analysis. RESULTS AND DISCUSSION: A significantly higher MDR1 3435T variant frequency was observed in Uygur (52.8%), than in Kazakh (39.8%) and Han (37.9%) Chinese (P < 0.01, Fisher's exact test). There was no significant difference in MDR1 1236T and 2677T/A variant frequencies between Han, Uygur and Kazakh. CYP3A5*3 (G) allele was observed at intermediate frequencies in Uygur (84.8%) and Kazakh (86.6%), relative to Han (72.7%) and values previously reported in Caucasians (91.7%). The CYP3AP1*3 (A) allele was strongly linked to CYP3A5*3 in Chinese Han, Uygur and Kazakh. CONCLUSION: Significant interethnic differences in MDR1 haplotype and CYP3A5 variant frequencies exist between mainland Chinese Han and Caucasians, and the intermediate frequencies observed in Chinese Uygur and Kazakh might be due to the genetic admixture of Eurasians and Orientals. | ||||||||
| 1076 | 34.86 | 8528206 | 1996.01.26 | + | + | Gilbert's syndrome is caused by a heterozygous missense mutation in the gene for bilirubin UDP-glucuronosyltransferase. | Hum Mol Genet | |
| O Koiwai, M Nishizawa, K Hasada, S Aono, Y Adachi, N Mamiya, H Sato, | ||||||||
| Gilbert's syndrome, which is characterized by chronic, non-hemolytic unconjugated hyperbilirubinemia, is caused by a reduction in the activity of hepatic bilirubin UDP-glucuronosyltransferase (UGT). Here, we report that all examined patients with this disease carried missense mutations in the gene for UGT and that the mutations were heterozygous. An expression study in COS cells in vitro, using the expression vector pcDL that carried the mutated gene for UGT from a patient, indicated that approximately 14% of the normal UGT activity was expressed. However, the UGT activity of the patient with Gilbert's syndrome was unexpectedly < 50% of the normal, perhaps as the result of the dominant negative nature of the mutation. | ||||||||
| 1077 | 34.86 | 9731716 | 1998.11.13 | + | + | Detection of mutations and polymorphism of N-acetyltransferase 1 gene in Indian, Malay and Chinese populations. | Pharmacogenetics | |
| B Zhao, EJ Lee, PN Yeoh, NH Gong, | ||||||||
| The xenobiotic metabolizing enzymes N-acetyltransferases (NATs) are important for the biotransformation and/or bioactivation of drugs and carcinogens. NATs are coded for in humans by two distinct genes, designated NAT1 and NAT2. NAT1, which was originally thought to be monomorphic, was recently reported to exhibit variation in human populations. Recent studies suggested that a genetic polymorphism of NAT1 may be associated with colorectal cancer risk. The distributions of NAT1 allele and genotype frequencies in unrelated individuals among Indian (n = 140), Malay (n = 122) and Chinese (n = 181) populations in Singapore were characterized by polymerase chain reaction-restriction fragment length polymorphism and allele-specific-polymerase chain reaction. The allelic frequencies of NAT1*3, NAT1*4, NAT1*10 and NAT1*11 among Indians were 0.3, 0.51, 0.17 and 0.02, respectively. The corresponding NAT1 allelic frequencies in Malays were 0.29, 0.30, 0.39 and 0.02, respectively, and were similar to those in Chinese in the region. The allelic frequencies of NAT1*3, NAT1*4, NAT1*10 and NAT1*11 among Chinese were 0.33, 0.35, 0.30 and 0.02, respectively. These findings are of importance for the determination of cancer risk in these populations. In addition, nucleotide changes at positions 350-351 (GG to CC) and 497-499 (GGG to CCC) of the NAT1 gene were not found in the alleles of the populations studied. | ||||||||
| 1078 | 34.85 | 15229244 | 2004.12.16 | + | + | YB-1 and CTCF differentially regulate the 5-HTT polymorphic intron 2 enhancer which predisposes to a variety of neurological disorders. | J Neurosci | |
| E Klenova, AC Scott, J Roberts, S Shamsuddin, EA Lovejoy, S Bergmann, VJ Bubb, HD Royer, JP Quinn, | ||||||||
| The serotonin transporter (5-HTT) gene contains a variable number tandem repeat (VNTR) domain within intron 2 that is often associated with a number of neurological conditions, including affective disorders. The implications of this polymorphism are not yet understood, however, we have previously demonstrated that the 5-HTT VNTR is a transcriptional regulatory domain, and the allelic variation supports differential reporter gene expression in vivo and in vitro. The aim of this study was to identify transcription factors responsible for the regulation of this VNTR. Using a yeast one-hybrid screen, we found the transcription factor Y box binding protein 1 (YB-1) interacts with the 5-HTT VNTR. Consistent with this, we demonstrate in a reporter gene assay that the polymorphic VNTR domains differentially respond to exogenous YB-1 and that YB-1 will bind to the VNTR in vitro in a sequence-specific manner. Interestingly, the transcription factor CCTC-binding factor (CTCF), previously shown to interact with YB-1, interferes with the ability of the VNTR to support YB-1-directed reporter gene expression. In addition, CTCF blocks the binding of YB-1 to its DNA recognition sequences in vitro, thus providing a possible mechanism of regulation of YB-1 activation of the VNTR by CTCF. Therefore, we have identified YB-1 and CTCF as transcription factors responsible, at least in part, for modulation of VNTR function as a transcriptional regulatory domain. Our data suggest a novel mechanism that explains, in part, the ability of the distinct VNTR copy numbers to support differential reporter gene expression based on YB-1 binding sites. | ||||||||
| 1079 | 34.84 | 12232775 | 2003.02.25 | + | + | Serotonin transporter promoter variants in autism: functional effects and relationship to platelet hyperserotonemia. | Mol Psychiatry | |
| GM Anderson, L Gutknecht, DJ Cohen, S Brailly-Tabard, JH Cohen, P Ferrari, PL Roubertoux, S Tordjman, | ||||||||
| The well-replicated platelet hyperserotonemia of autism has stimulated interest in serotonin (5-HT) in autism. We have examined the effects of the serotonin transporter gene (5-HTT, locus SLC6A4) promoter polymorphism (5-HTTLPR) on platelet 5-HT physiology in autism. Platelet 5-HT uptake rates and affinities (V(max) and K(m)), uptake site densities (B(max)) and 5-HT levels were examined in 31 French individuals with autism genotyped with respect to the 5-HTTLPR. Platelet 5-HT uptake and 5-HT levels were measured using HPLC; uptake sites were determined by radioligand binding. A 1.5-fold increased rate (V(max)) of platelet 5-HT uptake was observed in ll genotype individuals compared to those with ls and ss genotypes (Mann- Whitney U-test, P = 0.022). However, no significant relationship was observed between genotype and uptake site density (U-test, P = 0.51). Although median levels of platelet 5-HT in platelet-rich plasma were higher in the ll group, only trend level significance was observed (U-test, P= 0.069); platelet 5-HT content measured in whole blood was similar across genotypes. Uptake rates were well correlated with B(max) values (r = 0.66, P = 0.002); correlations between uptake and platelet 5-HT levels and between B(max) values and 5-HT levels were somewhat lower. While 5-HTTLPR alleles had an appreciable effect on platelet 5-HT uptake rates, effects on 5-HT levels and uptake site density were smaller or absent. Based on these preliminary data and prior studies of allele frequencies, we conclude that the 5-HTTLPR is not a major determinant of the group mean platelet serotonin elevation seen in autism. However, a role for increased uptake in the hyperserotonemia of autism can not be ruled out. In addition, it appears that studies of platelet 5-HT measures in autism and other disorders should take account of the effects of 5-HTTLPR genotype on 5-HT uptake | ||||||||
| 1080 | 34.84 | 10523821 | 1999.12.10 | + | + | Genetics of two mu opioid receptor gene (OPRM1) exon I polymorphisms: population studies, and allele frequencies in alcohol- and drug-dependent subjects. | Mol Psychiatry | |
| J Gelernter, H Kranzler, J Cubells, | ||||||||
| The gene encoding the mu opioid receptor, OPRM1, contains at least two polymorphisms affecting protein sequence in exon 1, Ala6Val and Asp40Asn. In previous studies, each variant has been reported to be associated with some form of drug dependence. Although past reports have not been consistent, they have also not considered comparable populations. The goals of the present study were to delineate allele and haplotype frequencies of these variants in a range of populations, and in drug- or alcohol-dependent subjects deriving from some of those populations. We developed new PCR-RFLP methods to detect both of these polymorphisms and studied them in control and substance-dependent populations of African American (AA), European American (EA) and Hispanic origin, and in a series of populations differing in geographic origin (Japanese, Ethiopians, Bedouins, and Ashkenazi Jews), 891 subjects overall. We designed primers flanking the DNA segment containing both polymorphisms, each primer creating a different artificial restriction site, such that a single PCR reaction can be completed, then divided, and the PCR product digested with either of two enzymes to reveal both polymorphisms. We found that allele frequencies for both polymorphic systems were significantly different between AA and EA subjects, and there was significant heterogeneity among the more extensive set of populations. Furthermore, there were no significant differences in allele frequency by diagnosis; that is, neither polymorphism appears to be a direct risk factor for substance dependence. Finally, we demonstrated linkage disequilibrium between the two exon 1 markers, and a previously described short tandem repeat (STR) marker. | ||||||||
| 1081 | 34.84 | 11891283 | 2002.04.24 | + | + | Genetic variation at the 22q11 PRODH2/DGCR6 locus presents an unusual pattern and increases susceptibility to schizophrenia. | Proc Natl Acad Sci U S A | |
| H Liu, SC Heath, C Sobin, JL Roos, BL Galke, ML Blundell, M Lenane, B Robertson, EM Wijsman, JL Rapoport, JA Gogos, M Karayiorgou, | ||||||||
| The location of a schizophrenia susceptibility locus at chromosome 22q11 has been suggested by genome-wide linkage studies. Additional support was provided by the observation of a higher-than-expected frequency of 22q11 microdeletions in patients with schizophrenia and the demonstration that approximately 20-30% of individuals with 22q11 microdeletions develop schizophrenia or schizoaffective disorder in adolescence and adulthood. Analysis of the extent of these microdeletions by using polymorphic markers afforded further refinement of this locus to a region of approximately 1.5 Mb. Recently, a high rate of 22q11 microdeletions was also reported for a cohort of 47 patients with Childhood Onset Schizophrenia, a rare and severe form of schizophrenia with onset by age 13. It is therefore likely that this 1.5-Mb region contains one or more genes that predispose to schizophrenia. In three independent samples, we provide evidence for a contribution of the PRODH2/DGCR6 locus in 22q11-associated schizophrenia. We also uncover an unusual pattern of PRODH2 gene variation that mimics the sequence of a linked pseudogene. Several of the pseudogene-like variants we identified result in missense changes at conserved residues and may prevent synthesis of a fully functional enzyme. Our results have implications for understanding the genetic basis of the 22q11-associated psychiatric phenotypes and provide further insights into the genomic instability of this region. | ||||||||
| 1082 | 34.83 | 12876480 | 2003.09.26 | + | + | Methionine synthase polymorphism is a risk factor for Alzheimer disease. | Neuroreport | |
| K Beyer, JI Lao, P Latorre, N Riutort, B Matute, MT Fernández-Figueras, JL Mate, A Ariza, | ||||||||
| Alzheimer disease (AD) patients show increased plasma levels of homocysteine, whose conversion to methionine is catalyzed by methionine synthase (MS). Although altered MS activity may result from the MS A2756G polymorphism, the latter's possible associ-ation with AD remains unexplored. To assess whether the MS A2756G polymorphism holds any influence on AD risk, we have analyzed 172 AD patients and 166 controls. We have also investigated whether the MS-A or MS-G allele interacts with the APOE4 allele. Our results indicate that association with the MS-AA genotype is an APOE4 allele-independent risk factor for AD. These findings provide novel evidence implicating genetic enzymatic alterations of homocysteine metabolic pathways in the pathogenesis of AD. | ||||||||
| 1083 | 34.83 | 10101149 | 1999.05.05 | + | + | Role of CYP2B6 and CYP3A4 in the in vitro N-dechloroethylation of (R)- and (S)-ifosfamide in human liver microsomes. | Drug Metab Dispos | |
| CP Granvil, A Madan, M Sharkawi, A Parkinson, IW Wainer, | ||||||||
| The central nervous system toxicity of ifosfamide (IFF), a chiral antineoplastic agent, is thought to be dependent on its N-dechloroethylation by hepatic cytochrome P-450 (CYP) enzymes. The purpose of this study was to identify the human CYPs responsible for IFF-N-dechloroethylation and their corresponding regio- and enantioselectivities. IFF exists in two enantiomeric forms, (R) - and (S)-IFF, which can be dechloroethylated at either the N2 or N3 positions, producing the corresponding (R,S)-2-dechloroethyl-IFF [(R, S)-2-DCE-IFF] and (R,S)-3-dechloroethyl-IFF [(R,S)-3-DCE-IFF]. The results of the present study suggest that the production of (R)-2-DCE-IFF and (S)-3-DCE-IFF from (R)-IFF is catalyzed by different CYPs as is the production of (S)-2-DCE-IFF and (R)-3-DCE-IFF from (S)-IFF. In vitro studies with a bank of human liver microsomes revealed that the sample-to-sample variation in the production of (S)-3-DCE-IFF from (R)-IFF and (S)-2-DCE-IFF from (S)-IFF was highly correlated with the levels of (S)-mephenytoin N-demethylation (CYP2B6), whereas (R)-2-DCE-IFF production from (R)-IFF and (R)-3-DCE-IFF production from (S)-IFF were both correlated with the activity of testosterone 6beta-hydroxylation (CYP3A4/5). Experiments with cDNA-expressed P-450 and antibody and chemical inhibition studies supported the conclusion that the formation of (S)-3-DCE-IFF and (S)-2-DCE-IFF is catalyzed primarily by CYP2B6, whereas (R)-2-DCE-IFF and (R)-3-DCE-IFF are primarily the result of CYP3A4/5 activity. | ||||||||
| 1084 | 34.82 | 9929518 | 1999.04.07 | + | + | Role of cytochrome P-4502C9 in irbesartan oxidation by human liver microsomes. | Drug Metab Dispos | |
| M Bourrié, V Meunier, Y Berger, G Fabre, | ||||||||
| The oxidative metabolism of irbesartan, a new nonpeptide angiotensin II receptor antagonist, was investigated on 12 human fully characterized hepatic microsomes and purified cytochrome P-450 (CYP) isoforms. After incubation of microsomes with irbesartan and NADPH, four main hydroxy metabolites were formed, as confirmed by liquid chromatography-mass spectrometry analysis. Irbesartan oxidation follows Michaelis-Menten kinetics, consistent with the involvement of a single CYP isoform in these hydroxylation processes. Only a low interindividual variability (2-fold difference) was observed in drug oxidation, even in preparations lacking CYP2D6. Km and Vmax for irbesartan oxidation were 54 +/- 6.5 microM and 0.62 +/- 0.18 nmol/min/mg, respectively. Irbesartan oxidation correlated (r2 = 0. 769) with tolbutamide (CYP2C9 substrate) 4-methyl-hydroxylation. Oxidation of irbesartan was markedly inhibited by sulfaphenazole (CYP2C9 inhibitor), but not by any of several other CYP inhibitors. In the same manner, both tolbutamide and warfarin (CYP2C9 substrates), were competitive-type inhibitors of irbesartan oxidation with Ki values of 500 and 30 microM, respectively. Moreover, irbesartan was a competitive-type inhibitor of tolbutamide 4-methylhydroxylation (Ki = 317 microM). Nifedipine also potentially decreased irbesartan oxidation, whereas neither ketoconazole and triacetyloleandomycin (CYP3A inhibitors), nor diltiazem and verapamil, (CYP3A4 substrates), exhibited an inhibitory effect. Additional studies demonstrated that nifedipine was an inhibitor of irbesartan (Ki = 20 microM) and tolbutamide oxidation processes, whereas irbesartan had no effect at all on nifedipine dehydrogenation. Enzyme kinetics suggest that nifedipine is a noncompetitive-type inhibitor of CYP2C9-mediated catalytic activities. Finally, only microsomes containing recombinant human liver CYP2C9 were capable of oxidizing irbesartan. These results provide evidence that CYP2C9 plays a major role in irbesartan oxidation. | ||||||||
| 1085 | 34.82 | 10970818 | 2000.09.29 | + | + | Enhanced expression of the leukotriene C(4) synthase due to overactive transcription of an allelic variant associated with aspirin-intolerant asthma. | Am J Respir Cell Mol Biol | |
| M Sanak, M Pierzchalska, S Bazan-Socha, A Szczeklik, | ||||||||
| Aspirin-intolerant asthma (AIA), a distinct clinical syndrome affecting about 10% of adult asthmatics, appears to be unusually dependent on cysteine leukotriene (cys-LT) overproduction by pulmonary eosinophils. The gene coding for leukotriene (LT) C(4) synthase (LTC(4)S), the enzyme controlling cys-LT biosynthesis, exists as two common alleles distinguished by an A to C transversion at a site 444 nucleotides upstream of the translation start. We tested the hypothesis that this single nucleotide polymorphism (SNP) affects binding of transcription factors and influences the transcription rate, predisposing to AIA. Gel shift assay studies revealed that the (-444)C allele, conferring an activator protein-2 binding sequence, is an additional target for a transcription factor of histone H4 consensus. Introduction of the H4TF-2 decoy oligonucleotide into LTC(4)S-positive, differentiated HL-60 cells decreased accumulation of LTC(4) to 68%. Transfection of COS-7 with promoter construct increased expression of beta-galactosidase reporter for the (-444)C variant. The (-444)C allelic frequency was significantly higher in AIA patients (n = 76) as compared with matched aspirin-tolerant asthmatics (n = 110) and healthy controls (n = 75). Patients with AIA had also upregulated LTC(4)S messenger RNA expression in peripheral blood eosinophils. An inhaled provocation test with lysine-aspirin led to an increase in urinary output of LTE(4), which reached statistical significance only in carriers of the (-444)C allele. Our results suggest that a transcription factor, present in dividing and bone marrow resident progenitors of eosinophils, triggers LTC(4)S transcription in carriers of a common (-444)C allele due to binding with the histone H4 promoter element of the gene. Genetic predisposition to cys-LT pathway upregulation, a hallmark of AIA, can be related to overactive expression of the LTC(4)S (-444)C allele. | ||||||||
| 1086 | 34.81 | 11966931 | 2002.08.02 | + | + | 5 polymorphisms in the transforming growth factor-beta 1 gene (TGF-beta 1) in adult periodontitis. | J Clin Periodontol | |
| LI Holla, A Fassmann, P Benes, T Halabala, V Znojil, | ||||||||
| OBJECTIVES: Transforming growth factor-beta (TGF-beta) represents a family of polypeptide growth factors, involved in inflammation and regulation of immune responses. The purpose of this study was to determine whether polymorphisms in the TGF-beta 1 gene may confer susceptibility to adult periodontitis. MATERIAL AND METHODS: We studied 90 patients with adult periodontitis together with 108 unrelated subjects. 3 polymorphisms located in the 5'region at positions -988 (C/A), -800 (G/A) and -509 (C/T) and 2 polymorphisms located at codons 10 (L10P) and 25 (R25P) of exon 1 were investigated by PCR methods. RESULTS: There was no statistically-significant difference in genotype or allele frequency distributions between patients and reference group for the -800G/A, -509C/T, L10P and R25P polymorphisms (p>0.05 in all cases). The -988 A polymorphism was present neither in our patients nor in unrelated subjects. Upon stratification for smoking status no significant differences were found in the TGF-beta 1 genotype or allele frequencies either between adult periodontitis smokers compared to control smokers, or between periodontitis non-smokers and control non-smokers. CONCLUSION: These data indicate that the mentioned polymorphisms of the TGF-beta 1 gene do not influence susceptibility to adult periodontitis. There was no association between any polymorphisms in the TGF-beta 1 gene, severity of periodontitis and the smoking status in our study. | ||||||||
| 1087 | 34.80 | 17015053 | 2006.10.24 | + | + | SLCO1B1 polymorphism and sex affect the pharmacokinetics of pravastatin but not fluvastatin. | Clin Pharmacol Ther | |
| M Niemi, MK Pasanen, PJ Neuvonen, | ||||||||
| OBJECTIVE: Pravastatin is a hydrophilic substrate and fluvastatin a lipophilic substrate of the hepatic uptake transporter organic anion transporting polypeptide 1B1 encoded by SLCO1B1. Our aim was to compare the effects of SLCO1B1 polymorphism on the pharmacokinetics of pravastatin and fluvastatin. METHODS: We recruited 4 healthy volunteers (3 men and 1 woman) with the homozygous SLCO1B1 c.521CC genotype, 12 (7 men and 5 women) with the heterozygous c.521TC genotype, and 16 (8 men and 8 women) with the homozygous c.521TT genotype (control subjects). In a crossover study each subject ingested a single 40-mg dose of fluvastatin and pravastatin with a washout period of at least 1 week. Plasma fluvastatin and pravastatin concentrations were measured for 12 hours. RESULTS: In men with the c.521CC genotype, the mean peak concentration in plasma and area under the plasma concentration-time curve from time 0 to infinity of pravastatin were 274% (95% confidence interval [CI], 92%-456%; P = .001) and 232% (95% CI, 74%-391%; P = .002) greater than those in men with the c.521TT genotype and 120% (95% CI, 11%-230%; P = .026) and 102% (95% CI, 3%-200%; P = .040) greater than those in men with the c.521TC genotype. In addition, women with the c.521TT genotype had a 147% (95% CI, 12%-281%; P = .028) greater peak concentration in plasma and a 142% (95% CI, 7%-242%; P = .034) greater area under the plasma concentration-time curve from time 0 to infinity than men with the c.521TT genotype. The pharmacokinetic variables of pravastatin were approximately similar among women with different SLCO1B1 genotypes. No significant differences were seen in the pharmacokinetics of fluvastatin between subjects with different SLCO1B1 genotypes or between the sexes. CONCLUSIONS: SLCO1B1 polymorphism has a large effect on the pharmacokinetics of pravastatin but not fluvastatin. This suggests that the lipophilic fluvastatin can penetrate the hepatocyte plasma membrane via passive diffusion or that uptake transporters other than organic anion transporting polypeptide 1B1 mainly mediate its hepatic uptake. Moreover, the results suggest that sex may affect the pharmacokinetics of pravastatin and possibly the functional consequences of SLCO1B1 polymorphism. | ||||||||
| 1088 | 34.79 | 11059786 | 2000.11.08 | + | + | Epidermal growth factor receptor transcriptionally up-regulates vascular endothelial growth factor expression in human glioblastoma cells via a pathway involving phosphatidylinositol 3'-kinase and distinct from that induced by hypoxia. | Cancer Res | |
| A Maity, N Pore, J Lee, D Solomon, DM O'Rourke, | ||||||||
| Glioblastomas are highly vascular malignant brain tumors that often overexpress vascular endothelial growth factor (VEGF). They also frequently overexpress epidermal growth factor receptor (EGFR) and contain regions of hypoxia, both conditions that can induce VEGF. We examined VEGF regulation in U87 MG human glioblastoma cells and in U87/T691 cells, a clonal derivative that contains a truncated erbB2/Neu receptor that interferes with EGFR signaling through the formation of nonfunctional heterodimeric receptor complexes. U87/T691 cells contained approximately one-half as much VEGF mRNA as did U87 MG cells under normoxic conditions (21% oxygen). Pharmacological inhibition of EGFR, Ras, or PI(3) kinase, but not MAP kinase, led to a significant decrease in VEGF mRNA levels in U87 MG cells. VEGF promoter activity in transient transfections was decreased by either pharmacological or genetic inhibition of EGFR, Ras, or phosphatidylinositol 3'-kinase [PI(3) kinase]. However, inhibition of PI(3) kinase or EGFR did not completely abolish induction of VEGF mRNA by hypoxia (0.2% oxygen). Likewise, VEGF mRNA expression was induced 3-fold by hypoxia in EGFR-inhibited U87/T691 cells, comparable with the fold induction seen in parental U87 MG cells, although the absolute level of message under hypoxia was higher in U87 MG cells. In transient transfections, a luciferase reporter construct containing a 1.2-kb fragment of the VEGF promoter, lacking the known hypoxic-responsive element (HRE), showed up-regulation after EGF stimulation to the same degree as the full-length, 1.5-kb VEGF promoter construct retaining the HRE. Furthermore, activity of the HRE-deleted, 1.2-kb promoter luciferase reporter was down-regulated by PI(3) kinase inhibition. Therefore, in glioblastoma cells, transcriptional regulation of the VEGF promoter by EGFR appears to involve Ras/PI(3) kinase and to be distinct from signals induced by hypoxia. | ||||||||
| 1089 | 34.78 | 15534626 | 2005.06.07 | + | + | Interethnic variability of ERCC2 polymorphisms. | Pharmacogenomics J | |
| CR King, J Yu, RR Freimuth, HL McLeod, S Marsh, | ||||||||
| Excision Repair Cross-Complementing Rodent Repair Group 2 (ERCC2) plays an important role in DNA repair by eliminating bulky DNA adducts produced by platinum agents during the nucleotide excision repair pathway. Several studies have associated polymorphisms in ERCC2 with response to platinum therapy, lung cancer risk, and DNA repair capacity. This study examined ERCC2 polymorphisms and haplotype structure across 18.9 kb in 95 European, 95 African, and 95 Asian individuals. Single-nucleotide polymorphisms (SNPs) (ERCC2 -9164 A>T, -1989 A>G, -516 G>A, 468 C>A [Arg156Arg], 1737 C>T [Val579Val], 2133 C>T [Asp711Asp], and 2251 T>G [Lys751Gln]) were mined and mapped using Golden Path, PolyMAPr, and Promolign. Genotyping was performed using PCR and pyrosequencing. Allele frequencies ranged from 0 to 0.47 (Europeans), 0.05 to 0.72 (Africans), and 0 to 0.47 (Asians). The synonymous cSNP at codon 579 could not be confirmed in our populations. There were significant differences in haplotype structure and frequency between populations. This information on ERCC2 genomic structure will allow the construction of definitive studies to clarify the clinical role of this important gene. | ||||||||
| 1090 | 34.78 | 15252722 | 2004.08.24 | + | + | Common founder effect of rapsyn N88K studied using intragenic markers. | J Hum Genet | |
| V Dunne, RA Maselli, | ||||||||
| Mutations in the human gene encoding rapsyn have been linked to a recessive form of postsynaptic congenital myasthenic syndrome due to deficient clustering of acetylcholine receptors at the endplate. All patients reported to date carry the N88K mutation, suggesting a possible common founder effect. To decrease the likelihood of a recombination event occurring within the span of neighboring microsatellite markers, we used seven intragenic single nucleotide polymorphisms (SNPs) spanning 8 kb to characterize the haplotype associated with N88K. In three affected N88K homozygous individuals, we identified a common haplotype present in all heterozygous carriers of N88K. Of note, in two asymptomatic N88K homozygous individuals, a second haplotype was present that differed at three SNP sites downstream from the N88K mutation. Our findings of a common haplotype associated with the N88K mutation support a founder effect. The discordant haplotype found in homozygous individuals suggests that recombination events may have occurred within the rapsyn gene and that this may have implications in the phenotypic expression of the disease. | ||||||||
| 1091 | 34.78 | 10913334 | 2000.08.24 | + | + | Homozygosity for the R1268Q mutation in MRP6, the pseudoxanthoma elasticum gene, is not disease-causing. | Biochem Biophys Res Commun | |
| DP Germain, J Perdu, V Remones, X Jeunemaitre, | ||||||||
| Pseudoxanthoma elasticum (PXE) is an inherited systemic disorder of connective tissue, characterized by progressive calcification of the elastic fibers in the eye, the skin, and the cardiovascular system, resulting in decreased vision, skin lesions, and life-threatening vascular disease, with highly variable phenotypic expression. The PXE locus has been mapped to chromosome 16p13.1, and was recently further refined to a 500 kb-region, containing two pseudogenes and four candidate genes. In a comprehensive mutational screening, we were able to exclude the responsibility of pM5, UNK, and MRP1 genes, candidate on the basis of their genetic localization. Conversely, we have found pathogenetic mutations in the MRP6 gene, in patients affected with PXE, indicating that human MRP6, which encodes a 1503 amino-acids membrane protein, member of the human ATP binding cassette (ABC) transporters superfamily, is the gene responsible for PXE. In one large PXE pedigree for which we had identified a nonsense mutation (R1141X), we came across a G to A transition at position 3803 of the MRP6 cDNA sequence (R1268Q). Astonishingly, this latter variant was found at the homozygous state in the proband's unaffected husband. We investigated the R1268Q mutation, and found the Q1268 allele at a relatively high frequency (0.19) in a Caucasian control population (n = 62 subjects). Genotype frequencies were in Hardy-Weinberg equilibrium, and three healthy volunteers were homozygous for the Q1268 allele. These data indicate that the R1268Q variant in the MRP6 gene does not cause PXE per se. Further studies will elucidate if it may play a role when found in compound heterozygotes. | ||||||||
| 1092 | 34.77 | 10958763 | 2000.10.31 | + | + | A comprehensive survey of sequence variation in the ABCA4 (ABCR) gene in Stargardt disease and age-related macular degeneration. | Am J Hum Genet | |
| A Rivera, K White, H Stöhr, K Steiner, N Hemmrich, T Grimm, B Jurklies, B Lorenz, HP Scholl, E Apfelstedt-Sylla, BH Weber, | ||||||||
| Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult onset and is caused by alterations in the gene encoding the photoreceptor-specific ATP-binding cassette (ABC) transporter (ABCA4). We have studied 144 patients with STGD and 220 unaffected individuals ascertained from the German population, to complete a comprehensive, population-specific survey of the sequence variation in the ABCA4 gene. In addition, we have assessed the proposed role for ABCA4 in age-related macular degeneration (AMD), a common cause of late-onset blindness, by studying 200 affected individuals with late-stage disease. Using a screening strategy based primarily on denaturing gradient gel electrophoresis, we have identified in the three study groups a total of 127 unique alterations, of which 90 have not been previously reported, and have classified 72 as probable pathogenic mutations. Of the 288 STGD chromosomes studied, mutations were identified in 166, resulting in a detection rate of approximately 58%. Eight different alleles account for 61% of the identified disease alleles, and at least one of these, the L541P-A1038V complex allele, appears to be a founder mutation in the German population. When the group with AMD and the control group were analyzed with the same methodology, 18 patients with AMD and 12 controls were found to harbor possible disease-associated alterations. This represents no significant difference between the two groups; however, for detection of modest effects of rare alleles in complex diseases, the analysis of larger cohorts of patients may be required. | ||||||||
| 1093 | 34.77 | 11309547 | 2001.05.17 | + | + | Effects of fluconazole and fluvoxamine on the pharmacokinetics and pharmacodynamics of glimepiride. | Clin Pharmacol Ther | |
| M Niemi, JT Backman, M Neuvonen, J Laitila, PJ Neuvonen, KT Kivistö, | ||||||||
| OBJECTIVE: Our objective was to study the effects of fluconazole and fluvoxamine on the pharmacokinetics and pharmacodynamics of glimepiride, a new sulfonylurea antidiabetic drug. METHODS: In this randomized, double-blind, three-phase crossover study, 12 healthy volunteers took 200 mg of fluconazole once daily (400 mg on day 1), 100 mg of fluvoxamine once daily, or placebo once daily for 4 days. On day 4, a single oral dose of 0.5 mg of glimepiride was administered. Plasma glimepiride and blood glucose concentrations were measured up to 12 hours. RESULTS: In the fluconazole phase, the mean total area under the plasma concentration-time curve of glimepiride was 238% (P <.0001) and the peak plasma concentration was 151% (P <.0001) of the respective control value. The mean elimination half-life of glimepiride was prolonged from 2.0 to 3.3 hours (P <.0001) by fluconazole. In the fluvoxamine phase, the mean area under the plasma concentration-time curve of glimepiride was not significantly different from that in the placebo phase. However, the mean peak plasma concentration of glimepiride was 143% (P <.05) of the control and the elimination half-life was prolonged from 2.0 to 2.3 hours (P <.01) by fluvoxamine. Fluconazole and fluvoxamine did not cause statistically significant changes in the effects of glimepiride on blood glucose concentrations. CONCLUSIONS: Fluconazole considerably increased the area under the plasma concentration-time curve of glimepiride and prolonged its elimination half-life. This was probably caused by inhibition of the cytochrome P-450 2C9-mediated biotransformation of glimepiride by fluconazole. Concomitant use of fluconazole with glimepiride may increase the risk of hypoglycemia as much as would a 2- to 3-fold increase in the dose of glimepiride. Fluvoxamine moderately increased the plasma concentrations and slightly prolonged the elimination half-life of glimepiride. | ||||||||
| 1094 | 34.76 | 10187776 | 1999.05.03 | + | + | The role of phosphatidylinositol 3-kinase in vascular endothelial growth factor signaling. | J Biol Chem | |
| GD Thakker, DP Hajjar, WA Muller, TK Rosengart, | ||||||||
| Vascular endothelial growth factor (VEGF) receptor Flk-1/KDR in endothelial cells is activated during vasculogenesis and angiogenesis upon ligand-receptor interaction. Activated Flk-1/KDR has been shown to recruit Src homology 2 domain-containing signaling molecules that are known to serve as links to the activation of the mitogen-activated protein (MAP) kinase signaling pathway. To define the functional significance of phosphatidylinositol (PI) 3-kinase in VEGF signaling, we have examined its role in human umbilical vein endothelial cell (HUVEC) cycle progression. We show herein that p85, the regulatory subunit of PI 3-kinase, is constitutively associated with Flk-1/KDR. The treatment of HUVECs with VEGF promoted tyrosine autophosphorylation of Flk-1/KDR and also induced phosphorylation of p85. This was followed by an increase in the PI 3-kinase activity, which was sensitive to wortmannin, a potent PI 3-kinase inhibitor. VEGF also induced a striking activation of MAP kinase in a time-dependent manner. Inhibition studies with both a dominant-negative p85 mutant and the PI 3-kinase inhibitor, wortmannin, were employed to show for the first time that VEGF-stimulated PI 3-kinase modulates MAP kinase activation and nuclear events such as transcription from c-fos promoter and entry into the synthesis (S)-phase. Our data demonstrate the importance of PI 3-kinase as a necessary signaling component of VEGF-mediated cell cycle progression. | ||||||||
| 1095 | 34.76 | 11960366 | 2002.05.07 | + | Polymorphisms in methylenetetrahydrofolate reductase and methotrexate sensitivity in childhood acute lymphoblastic leukemia. | Leukemia | ||
| JW Taub, LH Matherly, Y Ravindranath, GJ Kaspers, MG Rots, CH Zantwijk, | ||||||||
| 1096 | 34.74 | 11940092 | 2002.08.19 | + | + | A low prevalence of the C677T mutation in the methylenetetrahydrofolate reductase gene in Asian Indians. | Clin Genet | |
| M Mukherjee, S Joshi, S Bagadi, M Dalvi, A Rao, KR Shetty, | ||||||||
| The prevalence of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in Asian Indians from India was determined and the association of the mutant allele with coronary artery disease (CAD) was evaluated in a case-control study. The case group consisted of 251 patients with CAD; 195 male and 56 female aged from 29 to 82 years (mean age +/- SD, 57.5 +/- 10.6 years). The control group consisted of 216 apparently healthy individuals without evidence of CAD; 161 male and 55 female aged from 30 to 83 years (mean age +/- SD, 54.9 +/- 10.4 years). All the patients were assessed by coronary angiography. While 33 patients had normal coronaries, 23, 25 and 39 patients had single-vessel, two-vessel and triple-vessel disease, respectively. Eighty-three patients (33%) had suffered myocardial infarction less than a year to five years earlier. The C677T polymorphism in the MTHFR gene was assessed. While 31% of the controls and 38% of the patients had the heterozygous genotype, 2% of the control group and none of the patients had the mutant homozygous genotype. The overall 'T' allelic frequencies were comparable in control and patient groups (0.18 and 0.19, respectively), but the association of the sum of heterozygous and homozygous genotypes with CAD (1, 2 or 3-vessel disease) was statistically significant for females only [Odds ratio (95% confidence intervals), 2.8 (1.1-6.9), p = 0.023]. No association was found between genotype distribution and previous myocardial infarction or severity of atherosclerosis. | ||||||||
| 1097 | 34.74 | 11462242 | 2001.12.04 | + | + | Evidence of a founder mutation of BRCA1 in a highly homogeneous population from southern Italy with breast/ovarian cancer. | Hum Mutat | |
| F Baudi, B Quaresima, C Grandinetti, G Cuda, C Faniello, P Tassone, V Barbieri, R Bisegna, E Ricevuto, S Conforti, A Viel, P Marchetti, C Ficorella, P Radice, F Costanzo, S Venuta, | ||||||||
| Several genes have been involved in the pathogenesis of hereditary breast/ovarian cancer (BOC), but mutations in the BRCA1 gene are by far the most recurrent. In this study, we report the identification of a founder mutation in a geographically and historically homogeneous population from Calabria, a south Italian region. A screening performed on 24 patients from unrelated families highlighted the high prevalence of a 5083del19 alteration in the BRCA1 gene, which accounts for 33% of the overall gene mutations. The same mutation was also detected in 4 patients, all of Calabrian origin, referred to us by research centres from the north of Italy. Allelotype analysis, performed on probands and unaffected family members revealed the presence a common allele, therefore suggesting a founder effect due to a common ancestor. Our findings underscore the importance of ethnic background homogeneity in patients' selection and highlight the usefulness of founder mutations as a potential tool for optimisation of preclinical diagnosis in gene carriers and therapeutic approaches in affected individuals. | ||||||||
| 1098 | 34.73 | 11591709 | 2002.01.24 | + | + | The murine cysteinyl leukotriene 2 (CysLT2) receptor. cDNA and genomic cloning, alternative splicing, and in vitro characterization. | J Biol Chem | |
| Y Hui, G Yang, H Galczenski, DJ Figueroa, CP Austin, NG Copeland, DJ Gilbert, NA Jenkins, CD Funk, | ||||||||
| Two classes of cysteinyl leukotriene receptor, CysLT(1) and CysLT(2), have been identified and pharmacologically characterized in human tissues. Although the CysLT(1) receptor mediates the proinflammatory effects of leukotrienes in human asthma, the physiological roles of CysLT(2) receptor are not defined, and a suitable mouse model would be useful in delineating function. We report here the molecular cloning and characterization of the mouse CysLT(2) receptor (mCysLT(2)R) from heart tissue. mCysLT(2)R cDNA encodes a protein of 309 amino acids, truncated at both ends compared with the human ortholog (hCysLT(2)R). The gene resides on the central region of mouse chromosome 14 and is composed of 6 exons with the entire coding region located in the last exon. Two 5'-untranslated region splice variants were identified with the short form lacking exon 3 as the predominant transcript. Although the overall expression of mCysLT(2)R is very low, the highest expression was detected in spleen, thymus, and adrenal gland by ribonuclease protection assay, and discrete sites of expression in heart were observed by in situ hybridization. Intracellular calcium mobilization in response to cysteinyl leukotriene administration was detected in human embryonic kidney 293T cells transfected with recombinant mCysLT(2)R with a rank order of potency leukotriene C(4)(LTC(4) ) = LTD(4)>>LTE(4). [(3)H]LTD(4) binding to membranes expressing mCysLT(2)R could be effectively competed by LTC(4) and LTD(4) and only partially inhibited by LTE(4) and BAYu9773. The identification of mCysLT(2)R will be useful for establishing CysLT(2)R-deficient mice and determining novel leukotriene functions. | ||||||||
| 1099 | 34.72 | 12855226 | 2004.03.09 | + | + | Interaction between common folate polymorphisms and B-vitamin nutritional status modulates homocysteine and risk for a thrombotic event. | Mol Genet Metab | |
| Z Yates, M Lucock, | ||||||||
| We have assessed the relationship between homocysteine, its thiol metabolites, specific folate coenzymes, and vitamin B12 according to the two main functionally relevant genotype-genotype categories that maintain the balance between homocysteine transsulphuration to cysteine, and homocysteine remethylation via folate dependent methionine biosynthesis, namely 2756A-->G-MS/66A-->G-MSR and 677C-->T-MTHFR/1298A-->C-MTHFR. We examined 152 individuals who were being treated for either thromboembolic (TE) or non-thromboembolic (non-TE) events. Chi2 test for linear trend in odds ratio provides reasonable evidence for an altered risk of thromboembolism within the range of compound MS/MSR genotypes encountered (wt/wt-->recessive/recessive) (p< or =0.05), but not within the same range of MTHFR/MTHFR genotypes. Logistic regression analysis of the risk for a TE event gave OR=0.49 (95% CI, 0.26-0.92; p=0.026) for 2756A-->G-MS, OR=1.08 (95% CI, 0.65-1.78) for 66A-->G-MSR, OR=1.19 (95% CI, 0.69-2.06) for 677C-->T-MTHFR and OR=0.98 (95% CI, 0.52-1.85) for 1298A-->C-MTHFR. When genotypes were examined individually, one-way ANOVA showed only 677C-->T-MTHFR (p=0.005 [TE]) and 2756A-->G-MS (p=0.005 [non-TE] and p=0.0006 [all subjects]) influence homocysteine. One-way ANOVA also showed that MTHFR/MTHFR compound genotype significantly influences TE homocysteine distribution (p=0.044), but no other variable. In MS/MSR, homocysteine distribution is not significantly affected in TE subjects, but approaches significance in non-TE individuals (p=0.062). However, the increased power obtained when all subjects are analysed demonstrates a significant influence of MS/MSR upon homocysteine distribution (p=0.008). Other significant influences of MS/MSR were on total cellular 5-methyl-H4folate in non-TE subjects (p=0.042) and vitamin B12 in TE subjects (p=0.018). Given the central role of vitamin B12 in MS/MSR activity, 5-methyl-H4folate and homocysteine were also looked at by vitamin B12 quartile, independent of genotype: Vitamin B12 quartile significantly affected homocysteine distribution in TE (p=0.013) but not non-TE individuals, with no effect on 5-methyl-H4folate distributions. Similarly, the prevalence of clinical phenotypes (p=0.013) and of 'high risk' 2756A-->G-MS wildtypes (p=0.039) was associated with the disposition of homocysteine/B12 in TE but not non-TE subjects. Overall, results indicate compound MS/MSR genotype is associated with risk for a TE event. This may be related to variation in activity of the functional enzymes coded for by polymorphic forms of compound MS/MSR, resulting in altered catalytic cycling of methylcobalamin/cob(I)alamin, which in turn influences Hcy (and total 5-methyl-H4folate). The effect on vitamin B12 is greater in TE than non-TE subjects. The compound MTHFR/MTHFR genotype also influences variation in Hcy in TE subjects, but seemingly without the same level of mediation by vitamin B12. These results are consistent with accepted paradigms and offer a plausible explanation for the effect and interaction of specific SNPs in the TE phenotype. The biological implications of the limited number of MTHFR/MTHFR mutant alleles that can coexist, usually no more than two, may be explained by the serious consequences to folate status that these genotype combinations precipitate. We show that lowering of all folate 1-C pools occurs in the rare ct/cc compound genotype, except for the 5,10-methenyl-H4folate pool, which expands. 5,10-methenyl-H4folate is the immediate product of 5,10-methylene-H4folate, which is likely diverted away from methionine biosynthesis via the aberrant MTHFR enzyme. Consequences for the methylation cycle may be severe, and in most cases lethal for the developing embryo, where methylation is required for dozens of critical processes, but particularly for maintaining DNA methylation patterns that are now known to regulate the expression of half the complement of human genes via CpG islands located in the 5' promotor region, or within the first few exons of the gene. | ||||||||
| 1100 | 34.70 | 11500512 | 2001.12.04 | + | + | Characterization of the human ABCG1 gene: liver X receptor activates an internal promoter that produces a novel transcript encoding an alternative form of the protein. | J Biol Chem | |
| MA Kennedy, A Venkateswaran, PT Tarr, I Xenarios, J Kudoh, N Shimizu, PA Edwards, | ||||||||
| The human ABCG1 gene encodes a member of the ATP-binding cassette (ABC) superfamily of transporter proteins and is highly induced when macrophages are incubated with oxysterols. Using mRNA from oxysterol-treated human THP-1 cells together with 5'-rapid amplification of cDNA ends and polymerase chain reaction, we identified a novel ABCG1 transcript that encodes a putative protein of 786 residues containing a new amino terminus of 203 amino acids. Characterization of the genomic organization and structure of the human ABCG1 gene demonstrates that: (i) the gene consists of 23 exons spanning 98 kilobase pairs (kb) on chromosome 21q22.3, (ii) the 203 amino acids are encoded on three previously unidentified exons, 8-10, and (iii) a promoter, containing a TATA box and two liver X receptor (LXR) alpha response elements (LXREs), is located upstream of exon 8. Northern analysis using exon-specific probes confirms that oxysterol treatment results in >10-fold induction of ABCG1 transcripts that are derived from either exons 8-23 or exons 5, 7, and 11-23. Electromobility shift assays demonstrate that LXRalpha and retinoid X receptor alpha bind to the two LXREs in intron 7. Cells were transiently transfected with reporter luciferase constructs under the control of either (i) 9 kb of genomic DNA corresponding to intron 7 and part of exon 8 and containing either wild-type or mutant LXREs or (ii) two copies of the wild-type or mutant LXRE. In all cases, the wild-type construct was regulated in an LXR- and oxysterol-dependent manner, and this regulation was attenuated when the LXREs were mutated. In conclusion, the human ABCG1 gene contains multiple promoters, spans more than 98 kb and comprises 23 exons that give rise to alternative transcripts encoding proteins with different amino-terminal sequences. Elucidation of the various roles of different ABCG1 isoforms will be important for our understanding of mammalian cholesterol homeostasis. | ||||||||
| 1101 | 34.70 | 16595712 | 2006.08.31 | + | + | Expression, purification, and characterization of mouse CYP2d22. | Drug Metab Dispos | |
| AM Yu, RL Haining, | ||||||||
| Metabolism of the prototype human CYP2D6 substrates debrisoquine and bufuralol proceeds at a much slower rate in mice; therefore, the mouse has been proposed as an animal model for the human CYP2D6 genetic deficiency. To interpret the molecular mechanism of this deficiency, a cDNA belonging to the CYP2D gene subfamily (Cyp2d22) has been cloned and sequenced from a mouse mammary tumor-derived cell line. In the current study, Cyp2d22 enzyme was overexpressed and purified from insect cells using a baculovirus-mediated system. The activity of this purified enzyme was directly compared with purified human CYP2D6 toward codeine, dextromethorphan, and methadone as substrates. Purified Cyp2d22 was found to catalyze the O-demethylation of dextromethorphan with significantly higher K(m) values (250 microM) than that (4.2 microM) exhibited by purified human CYP2D6. The K(m) for dextromethorphan N-demethylation by Cyp2d22 was found to be 418 microM, much lower than that observed with human CYP2D6 and near the K(m) for dextromethorphan N-demethylation catalyzed by CYP3A4. CYP2D6 catalyzed codeine O-demethylation, whereas Cyp2d22 and CYP3A4 mediated codeine N-demethylation. Furthermore, methadone, a known CYP3A4 substrate and CYP2D6 inhibitor, was N-demethylated by Cyp2d22 with a K(m) of 517 microM and V(max) of 4.9 pmol/pmol/min. Quinidine and ketoconazole, potent inhibitors to CYP2D6 and CYP3A4, respectively, did not show strong inhibition toward Cyp2d22-mediated dextromethorphan O- or N-demethylation. These results suggest that mouse Cyp2d22 has its own substrate specificity beyond CYP2D6-like-deficient activity. | ||||||||
| 1102 | 34.70 | 11062481 | 2000.12.13 | + | + | A common variant in BRCA2 is associated with both breast cancer risk and prenatal viability. | Nat Genet | |
| CS Healey, AM Dunning, MD Teare, D Chase, L Parker, J Burn, J Chang-Claude, A Mannermaa, V Kataja, DG Huntsman, PD Pharoah, RN Luben, DF Easton, BA Ponder, | ||||||||
| Inherited mutations in the gene BRCA2 predispose carriers to early onset breast cancer, but such mutations account for fewer than 2% of all cases in East Anglia. It is likely that low penetrance alleles explain the greater part of inherited susceptibility to breast cancer; polymorphic variants in strongly predisposing genes, such as BRCA2, are candidates for this role. BRCA2 is thought to be involved in DNA double strand break-repair. Few mice in which Brca2 is truncated survive to birth; of those that do, most are male, smaller than their normal littermates and have high cancer incidence. Here we show that a common human polymorphism (N372H) in exon 10 of BRCA2 confers an increased risk of breast cancer: the HH homozygotes have a 1.31-fold (95% CI, 1.07-1.61) greater risk than the NN group. Moreover, in normal female controls of all ages there is a significant deficiency of homozygotes compared with that expected from Hardy-Weinberg equilibrium, whereas in males there is an excess of homozygotes: the HH group has an estimated fitness of 0.82 in females and 1.38 in males. Therefore, this variant of BRCA2 appears also to affect fetal survival in a sex-dependent manner. | ||||||||
| 1103 | 34.69 | 12915450 | 2004.05.19 | + | + | A novel genetic variant in the apolipoprotein A5 gene is associated with hypertriglyceridemia. | Hum Mol Genet | |
| JT Kao, HC Wen, KL Chien, HC Hsu, SW Lin, | ||||||||
| The apolipoprotein A5 gene (APOA5 ) has been shown to play an important role in determining plasma triglyceride concentrations in humans. We describe here a novel variant, c.553G>T, in the apolipoprotein A5 gene that is associated with hypertriglyceridemia. In contrast to some other polymorphisms, which occur in non-coding regions of the gene, this variant occurs within the coding region and causes the change of amino acid sequence (a substitution of a cysteine for a glycine residue). The minor allele frequencies were 0.042 and 0.27 (P<0.001) for control and hypertriglyceridemic patients, respectively. The serum triglyceride level was significantly different among the genotypic groups (G/G 92.5+/-37.8 mg/dl, G/T 106.6+/-34.8 mg/dl, T/T 183.0 mg/dl, P=0.014) in control subjects. Multiple logistic regression revealed individuals carrying the minor allele had age, gender and BMI (body mass index)-adjusted odds ratio of 11.73 (95% confidence interval of 6.617-20.793; P<0.0001) for developing hypertriglyceridemia in comparison to individuals without that allele. These findings suggest the possible use of c.553G>T polymorphisms in APOA5 as prognostic indicators for hypertriglyceridemia susceptibility in Chinese. | ||||||||
| 1104 | 34.69 | 15527968 | 2005.01.03 | + | + | A novel gene family induced by acute inflammation in endothelial cells. | Gene | |
| K Warton, NC Foster, WA Gold, KK Stanley, | ||||||||
| The aim of this study was to characterise a novel family of inflammatory genes induced by pro-inflammatory cytokines in primary human endothelial cells. Using a genome-wide array screen two previously uncharacterised genes, NLF1 and NLF2 were identified that were upregulated over 30 fold by treatment with interleukin 1beta for 2 h. They were also found to respond to tumour necrosis factor alpha, suggesting a general role in inflammation. Expression of both genes peaked 2 h after addition of interleukin 1beta, with similar kinetics to the fastest nuclear factor kappaB (NF-kappaB) induced genes. The activation of both genes by interleukin 1beta was abrogated by the proteasomal inhibitor, lactacystin which blocks activation of NF-kappaB by preventing IkappaB degradation. Furthermore, two sequences with homology to NF-kappaB binding sites in the promoter of NLF1 were found to be essential for rapid elevation in expression in response to interleukin 1beta. NLF1 and NLF2 transcripts were found predominantly in endothelial cells, and the encoded proteins were localised to the nuclear compartment suggesting a role in the regulation of transcription. Transfection of recombinant NLF into endothelial cells resulted in upregulation of the Rho kinases, Rnd1 and Gem GTPase. We propose that NLF1 and NLF2 belong to a novel gene family encoding nuclear factors with a role in regulating genes which control cellular architecture. This might increase vascular permeability in acute inflammation. | ||||||||
| 1105 | 34.69 | 10471394 | 1999.10.07 | + | + | Characterization of the VEGF binding site on the Flt-1 receptor. | Biochem Biophys Res Commun | |
| MT Herley, Y Yu, RG Whitney, JD Sato, | ||||||||
| The angiogenic growth factor VEGF binds to the receptor tyrosine kinases Flt-1 and KDR/Flk-1. Immunoglobulin (Ig)-like loop-2 of Flt-1 is involved in binding VEGF, but the contribution of other Flt-1 Ig-loops to VEGF binding remains unclear. We tested the ability of membrane-bound chimeras between the extracellular domain of Flt-1 and the cell adhesion molecule embigin to bind VEGF. VEGF bound as well to receptors containing Flt-1 loops 1-2 or 2-3 as it did to the entire Flt-1 extracellular domain. Chimeras containing only loop-2 of Flt-1 bound VEGF with 22-fold lower affinity. We conclude that high-affinity VEGF binding requires Ig-like loop-2 plus either loop-1 or loop-3. In addition, Flt-1 amino acid residues Arg-224 and Asp-231 were not essential for high-affinity binding of VEGF to membrane-bound Flt-1. | ||||||||
| 1106 | 34.69 | 11136233 | 2001.04.26 | + | + | Mutations in the small heterodimer partner gene are associated with mild obesity in Japanese subjects. | Proc Natl Acad Sci U S A | |
| H Nishigori, H Tomura, N Tonooka, M Kanamori, S Yamada, K Sho, I Inoue, N Kikuchi, K Onigata, I Kojima, T Kohama, K Yamagata, Q Yang, Y Matsuzawa, T Miki, S Seino, MY Kim, HS Choi, YK Lee, DD Moore, J Takeda, | ||||||||
| Mutations in several genes encoding transcription factors of the hepatocyte nuclear factor (HNF) cascade are associated with maturity-onset diabetes of the young (MODY), a monogenic form of early-onset diabetes mellitus. The ability of the orphan nuclear receptor small heterodimer partner (SHP, NR0B2) to modulate the transcriptional activity of MODY1 protein, the nuclear receptor HNF-4alpha, suggested SHP as a candidate MODY gene. We screened 173 unrelated Japanese subjects with early-onset diabetes for mutations in this gene and found five different mutations (H53fsdel10, L98fsdel9insAC, R34X, A195S, and R213C) in 6 subjects as well as one apparent polymorphism (R216H), all present in the heterozygous state. Interestingly, all of the subjects with the mutations were mildly or moderately obese at onset of diabetes, and analysis of the lineages of these individuals indicated that the SHP mutations were associated with obesity rather than with diabetes. Therefore, an additional group of 101 unrelated nondiabetic subjects with early-onset obesity was screened for mutations in the SHP gene. Two of the previously observed mutations (R34X and A195S) and two additional mutations (R57W and G189E) were identified in 6 subjects, whereas no mutations were identified in 116 young nondiabetic lean controls (P = 0.0094). Functional studies of the mutant proteins show that the mutations result in the loss of SHP activity. These results suggest that genetic variation in the SHP gene contributes to increased body weight and reveal a pathway leading to this common metabolic disorder in Japanese. | ||||||||
| 1107 | 34.67 | 10949931 | 2000.09.07 | + | + | Induction of p21WAF1 expression via Sp1-binding sites by tamoxifen in estrogen receptor-negative lung cancer cells. | Oncogene | |
| TH Lee, LY Chuang, WC Hung, | ||||||||
| Although originally synthesized as an anti-estrogen, tamoxifen (Tam) was found to be able to inhibit proliferation of estrogen receptor (ER)-negative cancer cells in vitro. However, the molecular basis of such ER-independent growth inhibition is largely unknown. We have previously demonstrated that Tam induces p21WAF1 and p27KIP1 expression in human lung cancer cells which lack ER-alpha and -beta. We found that Tam induced p21WAF1 expression via transcriptional activation. In order to determine the molecular mechanism responsible for p21WAF1 induction by Tam, we performed a deletion analysis on the p21WAF1 promoter. The minimal region in the p21WAF1 promoter required for Tam-activated induction was mapped to a contiguous stretch of 10 bp located 83 bases upstream of the transcription initiation site. Our results showed that transcription factor Sp1 and Sp3 bound to this GC-rich region and mutation of Sp1-binding sites dramatically attenuated Tam-induced p21WAF1 promoter activity. We also tried to elucidate the signaling pathway that mediated the activation of p21WAF1 by Tam. Inhibition of mitogen-activated protein kinase pathways did not block Tam-induced p21WAF1. Similarly, protein kinase C inhibitor calphostin C could not suppress Tam-induced p21WAF1. Conversely, pretreatment of a specific protein kinase A inhibitor H89 significantly attenuated the induction of p21WAF1 by Tam. Furthermore, PKA activators forskolin and dibutyryl-cAMP activated p21WAFI promoter activity and increased p21wAF1 protein level in lung cancer cells. Taken together, these results demonstrate that Tam activates the p21WAF1 promoter via Sp1-binding sites and suggest that PKA may be involved in the induction of p21wAF1 by Tam in ER-negative lung cancer cells. | ||||||||
| 1108 | 34.67 | 10232580 | 1999.05.20 | + | + | Methylation of CpG in a small region of the hMLH1 promoter invariably correlates with the absence of gene expression. | Cancer Res | |
| G Deng, A Chen, J Hong, HS Chae, YS Kim, | ||||||||
| Microsatellite instability (MSI) has been described in tumors from patients with hereditary nonpolyposis colorectal cancer, sporadic colorectal cancer, and other types of cancers. MSI is caused by the dysfunction of mismatch repairs genes. Loss of expression and mutation in one of the major mismatch repair genes, hMLH1, and the methylation of CpG sites in its promoter occur frequently in primary tumors and cell lines of colorectal cancer with MSI. To understand the mechanisms involved in the silencing of hMLH1 expression by methylation, we examined the methylation status of all CpG sites in the hMLH1 promoter in 24 colorectal cancer cell lines by the NaHSO3-sequencing method. We identified a small proximal region (-248 to -178, relative to the transcription start site) in the promoter in which the methylation status invariably correlates with the lack of hMLH1 expression. This correlation was further supported by the observation that cell lines that showed methylation-suppressed hMLH1 expression can be induced to reexpress hMLH1 by a methyl transferase inhibitor, 5-aza-2'-deoxycytidine, and the small region that we identified exhibited significant demethylation in all cell lines examined. | ||||||||
| 1109 | 34.67 | 15970796 | 2005.10.13 | + | + | Association analysis of cysteinyl-leukotriene receptor 2 (CYSLTR2) polymorphisms with aspirin intolerance in asthmatics. | Pharmacogenet Genomics | |
| JS Park, HS Chang, CS Park, JH Lee, YM Lee, JH Choi, HS Park, LH Kim, BL Park, YH Choi, HD Shin, | ||||||||
| OBJECTIVES AND METHODS: The cysteinyl leukotriene receptor 2 (CYSLTR2) gene on chromosome 13q14.12-q21.1 encodes a receptor for CYSLTs, potent biological mediators in the pathogenesis of asthma, particularly that associated with aspirin intolerance (AIA). In an effort to discover additional polymorphism(s), the variant(s) of which have been implicated in asthma and aspirin intolerance, we scrutinized genetic polymorphisms of the CYSLTR2 gene, and evaluated this locus as a potential candidate for asthma. RESULTS: DNA sequencing in 24 Koreans of the 5-kb region of the CYSLTR2 gene, including the approximately 1500-bp promoter region, revealed four sequence variants: one in the 5'-flanking region (c.-819T>G), two in the 3'-flanking region (c.2078C>T and c.2534A>G), and one downstream of the gene (c.2545+297A>G). The SNP frequencies were 0.499 (c.-819T>G), 0.351 (c.2078C>T), 0.429 (c.2534A>G), and 0.088 (c.2545+297A>G), and five haplotypes were constructed. The SNPs and haplotypes were not associated with risk of asthma development, but were significantly associated with aspirin intolerance. The frequencies of rare alleles on c.-819T>G, c.2078C>T, and c.2534A>G were higher in subjects with AIA than in subjects with aspirin-tolerant asthma (P=0.013-0.031). Asthmatics who had rare alleles for c.-819T>G, c.2078C>T or c.2534A>G exhibited a more pronounced fall in FEV1 after aspirin provocation than did those who carried the common allele (P=0.03-0.009). Asthmatics carrying ht2 (TTGA) also showed a more pronounced decrease in FEV1% after aspirin provocation than those carrying ht1 (GCGA) (P=0.006). These associations were even stronger when combined with LTC4S polymorphisms (-444A>C [c.-444A>C]) gene. CONCLUSION: CYSLTR2 polymorphisms are associated with aspirin intolerance in asthmatics. | ||||||||
| 1110 | 34.67 | 9359705 | 1997.12.09 | + | + | Increased sensitivity to anticancer drugs and decreased inflammatory response in mice lacking the multidrug resistance-associated protein. | Nat Med | |
| J Wijnholds, R Evers, MR van Leusden, CA Mol, GJ Zaman, U Mayer, JH Beijnen, M van der Valk, P Krimpenfort, P Borst, | ||||||||
| The multidrug resistance-associated protein (MRP) mediates the cellular excretion of many drugs, glutathione S-conjugates (GS-X) of lipophilic xenobiotics and endogenous cysteinyl leukotrienes. Increased MRP levels in tumor cells can cause multidrug resistance (MDR) by decreasing the intracellular drug concentration. The physiological role or roles of MRP remain ill-defined, however. We have generated MRP-deficient mice by using embryonic stem cell technology. Mice homozygous for the mrp mutant allele, mrp-/-, are viable and fertile, but their response to an inflammatory stimulus is impaired. We attribute this defect to a decreased secretion of leukotriene C4 (LTC4) from leukotriene-synthesizing cells. Moreover, the mrp-/- mice are hypersensitive to the anticancer drug etoposide. The phenotype of mrp-/- mice is consistent with a role for MRP as the main LTC4-exporter in leukotriene-synthesizing cells, and as an important drug exporter in drug-sensitive cells. Our results suggest that this ubiquitous GS-X pump is dispensable in mice, making treatment of MDR with MRP-specific reversal agents potentially feasible. | ||||||||
| 1111 | 34.66 | 10591546 | 2000.01.06 | + | + | Alpha1A-adrenergic receptor polymorphism: association with ethnicity but not essential hypertension. | Pharmacogenetics | |
| HG Xie, RB Kim, CM Stein, JV Gainer, NJ Brown, AJ Wood, | ||||||||
| The alpha1-adrenergic receptor (alpha1-AR) mediates vasoconstriction and plays an important role in the regulation of vascular tone. Increased alpha1-AR-mediated vasoconstrictor sensitivity, increased vascular reactivity to stress, and an increased prevalence of hypertension occur in African-Americans. The human alpha1A-AR is the predominant alpha1-AR subtype in vascular smooth muscle. The potential relevance of alpha1A-AR genetic variation to ethnic differences in vascular response and to the pathogenesis of hypertension prompted us to determine the frequency distribution of a recently identified polymorphism (Arg492 to Cys) in the alpha1A-AR in normotensive and hypertensive black and white American individuals. Polymerase chain reaction-based PstI restriction fragment length polymorphisms in the human alpha1A-AR gene were determined in 231 African-American and 282 Caucasian individuals, both with and without hypertension. There were marked differences in the genotypic and allelic distributions of the Arg492 to Cys alpha1A-AR polymorphism between African-American and Caucasian individuals (Cys492/Cys492 genotype, normotensive: 7.6% versus 30.1%; hypertensive: 7.1% versus 26.2%; Cys492 allele, normotensive: 29.5% versus 53.8%; hypertensive: 28.8% versus 55.2%; blacks versus whites, P < 0.0001). The frequency of the variant Cys492 allele was similar in normotensive and hypertensive individuals, both in African-Americans (29.5% versus 28.8%) and Caucasians (53.8% versus 55.2%). There were no significant intergenotypic differences in blood pressure (all P > 0.05). The data indicate that this polymorphism is not associated with essential hypertension in black or white Americans, but that the frequency of the alpha1A-AR Arg492 allele occurs significantly more commonly in African-Americans than in Caucasians. The potential role of the Arg492 to Cys alpha1A-AR polymorphism in ethnic differences in vascular alpha1-adrenergic response requires further investigation. | ||||||||
| 1112 | 34.66 | 11810297 | 2002.05.09 | + | + | Genetic variations in the cholesteryl ester transfer protein gene and high density lipoprotein cholesterol levels in Taiwanese Chinese. | Hum Genet | |
| LA Hsu, YL Ko, KH Hsu, YH Ko, YS Lee, | ||||||||
| This study analyzed the association of the I14A mutation, the D442G mutation, and the TaqIB polymorphism of the cholesteryl ester transfer protein (CETP) gene in 718 Chinese individuals with high-density lipoprotein cholesterol levels (HDL-C) living in Taiwan. The analysis revealed that the I14A mutation was not present in any of the 110 subjects with HDL-C levels above 60 mg/dl. By contrast, the D442G mutation was present in 48 of the 718 (6.7%) subjects tested. Significantly higher HDL-C levels were noted for bearers of the D442G mutation compared with non-bearers; however, this association was weaker for males and for subjects carrying the TaqIB1 allele. The TaqIB2 allele was also associated with higher HDL-C levels. From multivariate analysis, independent associations were demonstrated for the TaqIB2 polymorphism and the D442G mutation, and elevated HDL-C levels. For obese subjects, however, the presence of the TaqIB2 or D442G allele was not associated with increased HDL-C levels. For subjects with triglycerides at a concentration greater than 150 mg/dl, the association of both alleles with HDL-C levels was also diminished. Thus, genetic variation at the CETP gene locus may account for a significant proportion of the difference in HDL-C levels; however, it seems reasonable to suggest that the effects of the allele interact with genetic variations expressed within the sample population, and with sex, obesity, and plasma triglyceride levels. | ||||||||
| 1113 | 34.66 | 9511180 | 1998.04.21 | + | + | A rare CYP19 (aromatase) variant may increase the risk of breast cancer. | Pharmacogenetics | |
| VN Kristensen, TI Andersen, A Lindblom, B Erikstein, P Magnus, AL Børresen-Dale, | ||||||||
| The aromatase P450 (coded by the CYP19 gene) is responsible for the rate limiting step in the metabolism of C19 steroids to estrogens and is expressed in most breast carcinomas. A polymorphic tetranucleotide repeat (TTTA)n in intron 5, about 80 nucleotides downstream of exon 4 has previously been described. The allele frequencies of the polymorphic repeat were studied in series of 182 sporadic and 185 familial breast cancer patients as well as in 252 healthy control individuals. Five different alleles containing 7, 8, 9, 11 and 12-TTTA-repeats were detected. A relatively rare allele (A1) containing the longest repeat (TTTA)12 was found significantly more frequently in breast cancer patients than in control individuals. This indicates that individuals carrying the A1 allele of CYP19 may have an increased risk of developing breast cancer, OR 2.42 (95% confidence interval [CI] 1.03-5.80). The higher frequency was observed in both sporadic and familial patients, although when each of the groups was compared to the control group only a borderline significance was seen. A higher frequency of A1 allele carriers was also found in the group of patients with positive estrogen receptor and progesterone receptor positive tumors. These data suggest that the CYP19 gene may be involved as a low penetrance gene in breast cancer susceptibility. | ||||||||
| 1114 | 34.65 | 9860067 | 1998.12.30 | + | + | The effects of genetic polymorphisms of CYP2C9 and CYP2C19 on phenytoin metabolism in Japanese adult patients with epilepsy: studies in stereoselective hydroxylation and population pharmacokinetics. | Epilepsia | |
| K Mamiya, I Ieiri, J Shimamoto, E Yukawa, J Imai, H Ninomiya, H Yamada, K Otsubo, S Higuchi, N Tashiro, | ||||||||
| PURPOSE: The aim of this study was to clarify the effects of genetic polymorphisms of cytochrome P450 (CYP) 2C9 and 2C19 on the metabolism of phenytoin (PHT). In addition, a population pharmacokinetic analysis was performed. METHODS: The genotype of CYP2C9 (Arg144/Cys, Ile359/Leu) and CYP2C19(*1, *2 or *3) in 134 Japanese adult patients with epilepsy treated with PHT were determined, and their serum concentrations of 5-(4-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) enantiomers, being major metabolites of PHT, were measured. A population pharmacokinetic analysis (NONMEM analysis) was performed to evaluate whether genetic polymorphism of CYP2C9/19 affects the clinical use of PHT by using the 336 dose-serum concentration data. RESULTS: The mean maximal elimination rate (Vmax) was 42% lower in the heterozygote for Leu359 allele in CYP2C9, and the mean Michaelis-Menten constants (Km) in the heterozygous extensive metabolizers and the poor metabolizers of CYP2C19 were 22 and 54%, respectively, higher than those without the mutations in CYP2C9/19 genes. (R)- and (S)-p-HPPH/PHT ratios were lower in patients with mutations in CYP2C9 or CYP2C19 gene than those in patients without mutations. CONCLUSIONS: Although the hydroxylation capacity of PHT was impaired with mutations of CYP2C9/19, the impairment was greater for CYP2C9. In view of the clinical use of PHT, two important conclusions were derived from this population study. First, the serum PHT concentration in patients with the Leu359 allele in CYP2C9 would increase dramatically even at lower daily doses. Second, the patients with CYP2C19 mutations should be treated carefully at higher daily doses of PHT. | ||||||||
| 1115 | 34.65 | 7842002 | 1995.03.09 | The glittering prize. | Nat Genet | |||
| 1116 | 34.64 | 15280437 | 2005.01.13 | + | + | Haplotype-oriented genetic analysis and functional assessment of promoter variants in the MDR1 (ABCB1) gene. | J Pharmacol Exp Ther | |
| H Takane, D Kobayashi, T Hirota, J Kigawa, N Terakawa, K Otsubo, I Ieiri, | ||||||||
| Recently, a number of nucleotide variants have been described in the multidrug resistance 1 (MDR1/ABCB1) gene; however, most studies have focused on the coding region. In the present study, we identified promoter variants of the MDR1 gene and evaluated their phenotypic consequences using a reporter gene assay and the real-time polymerase chain reaction method. Ten allelic variants were detected in the promoter region (approximately 2 kilobases), seven of which were newly identified. Certain mutations occurred simultaneously, and a total of 10 haplotypes were observed. These promoter polymorphisms were found more frequently in Japanese than Caucasians. Some haplotypes were associated with changes in luciferase activity and placental and hepatic mRNA levels. We also determined DNA methylation status in the proximal promoter region of the MDR1 gene. The promoter region around potential binding sites for transcription factors was found to be hypomethylated and thus likely to be independent of the gene expression. Nucleotide and/or haplotype variants not only in the coding region but also in the promoter region of the MDR1 gene may be important for interindividual differences of P-glycoprotein expression. | ||||||||
| 1117 | 34.64 | 7987405 | 1995.01.10 | + | + | The influence of environmental and genetic factors on CYP2D6, CYP1A2 and UDP-glucuronosyltransferases in man using sparteine, caffeine, and paracetamol as probes. | Pharmacogenetics | |
| KW Bock, D Schrenk, A Forster, EU Griese, K Mörike, D Brockmeier, M Eichelbaum, | ||||||||
| The impact of gender, use of oral contraceptive steroids (OCS), coffee consumption and of smoking on the metabolism of sparteine, caffeine, and paracetamol was studied in 194 randomly selected subjects (98 male and 95 female). Thirty-eight of the male volunteers were cigarette smokers, 40 of the female subjects were smokers and/or users of OCS. The metabolic ratio of sparteine oxidation (MRs) showed a trimodal distribution. 7.7% of the subjects had a MRs > 20 and thus were poor metabolizers (PMs). Within the extensive metabolizer (EM) subjects, a distinct subgroup accounting for 11% was observed with 20 > MRs > 1.2. Six of the 15 phenotypical PMs were heterozygous EMs by genotyping. This indicates the existence of one or several CYP2D6 mutations which cannot be identified by the currently employed genotyping methods. In each subgroup, i.e. smokers/OCS and non-smokers/non-OCS, the cumulative frequency distribution of the heterozygous (wt/B) phenotype caused a shift to higher MRs compared with the wild-type homozygotes (wt/wt). Thus, for the in vivo activity of CYP2D6, genetic determinants prevail over environmental factors. Smoking, use of oral contraceptive steroids, caffeine consumption, or gender had no influence on sparteine metabolism. The distribution of the paracetamol glucuronide/paracetamol metabolic ratio appeared to be unimodal although skewed. Glucuronidation capacity was clearly affected by gender, OCS use and smoking. It was higher in male than in female subjects. Male smokers had the highest, and female non-smokers/non-OCS users the lowest metabolic ratio. CYP1A2 activity, as determined by a caffeine metabolic ratio ((AFMU + 1X + 1U)/1, 7U), was multimodally distributed and was clearly increased in smokers. It was significantly correlated to paracetamol glucoronidation in male heavy smokers (r=0.85), suggesting an element of co-regulation of CYP1A2 and of paracetamol conjugating UDP-glucuronosyltransferase isozymes, including UGTI.6. | ||||||||
| 1118 | 34.64 | 10511062 | 1999.10.22 | + | + | Effects of clarithromycin on the metabolism of omeprazole in relation to CYP2C19 genotype status in humans. | Clin Pharmacol Ther | |
| T Furuta, K Ohashi, K Kobayashi, I Iida, H Yoshida, N Shirai, M Takashima, K Kosuge, H Hanai, K Chiba, T Ishizaki, E Kaneko, | ||||||||
| BACKGROUND AND PURPOSE: A triple therapy with omeprazole, amoxicillin (INN, amoxicilline), and clarithromycin is widely used for the eradication of Helicobacter pylori. Omeprazole and clarithromycin are metabolized by CYP2C19 and CYP3A4. This study aimed to elucidate whether clarithromycin affects the metabolism of omeprazole. METHODS: After administration of placebo or 400 mg clarithromycin twice a day for 3 days, 20 mg omeprazole and placebo or 400 mg clarithromycin were administered to 21 healthy volunteers. Plasma concentrations of omeprazole and clarithromycin and their metabolites were determined before and 1, 2, 3, 5, 7, 10, and 24 hours after dosing. CYP2C19 genotype status was determined by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: Subjects were classified into three groups on the basis of PCR-RFLP analyses for CYP2C19: homozygous extensive metabolizer group (n = 6), heterozygous extensive metabolizer group (n = 11), and poor metabolizer group (n = 4). Mean area under the plasma concentration-time curves from 0 to 24 hours (AUC) of omeprazole in the homozygous extensive metabolizer, heterozygous extensive metabolizer, and poor metabolizer groups were significantly increased by clarithromycin from 383.9 to 813.1, from 1001.9 to 2110.4, and from 5589.7 to 13098.6 ng x h/mL, respectively. There were significant differences in the mean AUC values of clarithromycin among the three groups. CONCLUSION: Clarithromycin inhibits the metabolism of omeprazole. Drug interaction between clarithromycin and omeprazole may underlie high eradication rates achieved by triple therapy with omeprazole, amoxicillin, and clarithromycin. | ||||||||
| 1119 | 34.63 | 9452084 | 1999.06.30 | + | Identification of a novel splice-site mutation of the BRCA1 gene in two breast cancer families: screening reveals low frequency in Icelandic breast cancer patients. | Hum Mutat | ||
| JT Bergthorsson, A Jonasdottir, G Johannesdottir, A Arason, V Egilsson, S Gayther, A Borg, S Hakanson, S Ingvarsson, RB Barkardottir, | ||||||||
| 1120 | 34.63 | 17558303 | 2007.08.20 | + | + | The risk of myocardial infarction in patients with reduced activity of cytochrome P450 2C9. | Pharmacogenet Genomics | |
| LE Visser, RH van Schaik, AH Jan Danser, A Hofman, JC Witteman, CM van Duijn, AG Uitterlinden, HA Pols, BH Stricker, | ||||||||
| OBJECTIVE: The aim of the present follow-up study was to investigate whether the enzyme activity of the human cytochrome P450 (CYP) 2C9 isoenzyme is associated with myocardial infarction. METHODS: We investigated whether the variant alleles CYP2C9*2 and CYP2C9*3 or the use of CYP2C9 substrates or inhibitors was associated with an increased risk of myocardial infarction in 2210 men and 3534 women from the Rotterdam Study, a prospective population-based cohort study of individuals aged 55 years or older. RESULTS: In women, the use of CYP2C9 substrates or inhibitors was significantly associated with incident myocardial infarction with a hazard ratio of 2.48 (95% confidence interval: 1.55-3.96). Within the group of female carriers of a variant allele, the use of CYP2C9 substrates or inhibitors was associated with a fourfold increased risk of myocardial infarction (hazard ratio 3.86, 95% confidence interval: 1.93-7.75), as compared with non-use. Neither the use of CYP2C9 inhibitors or substrates nor the variant CYP2C9 alleles were associated with an increased risk of myocardial infarction in men. CONCLUSIONS: Drugs that are metabolized by CYP2C9 increase the risk of myocardial infarction in women. This risk was even higher in women with allelic variants of CYP2C9 with reduced enzyme activity. | ||||||||
| 1121 | 34.61 | 10089003 | 1999.05.07 | + | The association of the short variant of the 5-HTTPLR polymorphism and the apoE epsilon4 allele does not increase the risk for late onset Alzheimer's disease. | Mol Psychiatry | ||
| JR Oliveira, CM Shimokomaki, PR Brito-Marques, RM Gallindo, M Okuma, LG Maia, PA Otto, MR Passos-Bueno, M Zatz, | ||||||||
| 1122 | 34.60 | 17384146 | 2007.08.15 | + | + | Epigenetic regulation of human alpha1d-adrenergic receptor gene expression: a role for DNA methylation in Sp1-dependent regulation. | FASEB J | |
| GA Michelotti, DM Brinkley, DP Morris, MP Smith, RJ Louie, DA Schwinn, | ||||||||
| A growing body of evidence implicates alpha1-adrenergic receptors (alpha1ARs) as potent regulators of growth pathways. The three alpha1AR subtypes (alpha1aAR, alpha1bAR, alpha1dAR) display highly restricted tissue expression that undergoes subtype switching with many pathological stimuli, the mechanistic basis of which remains unknown. To gain insight into transcriptional pathways governing cell-specific regulation of the human alpha1dAR subtype, we cloned and characterized the alpha1dAR promoter region in two human cellular models that display disparate levels of endogenous alpha1dAR expression (SK-N-MC and DU145). Results reveal that alpha1dAR basal expression is regulated by Sp1-dependent binding of two promoter-proximal GC boxes, the mutation of which attenuates alpha1dAR promoter activity 10-fold. Mechanistically, chromatin immunoprecipitation data demonstrate that Sp1 binding correlates with expression of the endogenous gene in vivo, correlating highly with alpha1dAR promoter methylation-dependent silencing of both episomally expressed reporter constructs and the endogenous gene. Further, analysis of methylation status of proximal GC boxes using sodium bisulfite sequencing reveals differential methylation of proximal GC boxes in the two cell lines examined. Together, the data support a mechanism of methylation-dependent disruption of Sp1 binding in a cell-specific manner resulting in repression of basal alpha1dAR expression. | ||||||||
| 1123 | 34.60 | 11093784 | 2001.01.18 | + | + | Dexamethasone enhances constitutive androstane receptor expression in human hepatocytes: consequences on cytochrome P450 gene regulation. | Mol Pharmacol | |
| JM Pascussi, S Gerbal-Chaloin, JM Fabre, P Maurel, MJ Vilarem, | ||||||||
| The barbiturate phenobarbital induces the transcription of cytochromes P450 (CYPs) 2B through the constitutive androstane receptor (CAR; NR1I3). CAR is a member of the nuclear receptor family (NR1) mostly expressed in the liver, which heterodimerizes with retinoid X receptor (RXR) and was shown to transactivate both the phenobarbital responsive element module of the human CYP2B6 gene and the CYP3A4 xenobiotic response element. Because previous studies in rodent hepatocyte cultures have shown that the phenobarbital-mediated induction of CYP2B genes is potentiated by glucocorticoids, we examined the role of activated glucocorticoid receptor in this process. We show that submicromolar concentrations of dexamethasone enhance phenobarbital-mediated induction of CYP3A4, CYP2B6, and CYP2C8 mRNA in cultured human hepatocytes. In parallel, we observed that glucocorticoid agonists, such as dexamethasone, prednisolone, or hydrocortisone, specifically increase human car (hCAR) mRNA expression. Accumulation of hCAR mRNA parallels that of tyrosine aminotransferase: both mRNAs reach a maximum at a concentration of 100 nM dexamethasone and are down-regulated by concomitant treatment with the glucocorticoid antagonist RU486. Moreover, the effect of dexamethasone on hCAR mRNA accumulation appears to be of transcriptional origin because the addition of protein synthesis inhibitor cycloheximide has no effect, and dexamethasone does not affect the degradation of hCAR mRNA. Furthermore, dexamethasone increases both basal and phenobarbital-mediated nuclear translocation of CAR immunoreactive protein in human hepatocytes. The up-regulation of CAR mRNA and protein in response to dexamethasone explains the synergistic effect of this glucocorticoid on phenobarbital-mediated induction of CYP2B genes and the controversial role of the glucocorticoid receptor on phenobarbital-mediated CYP gene inductions. | ||||||||
| 1124 | 34.60 | 15527908 | 2004.12.17 | + | + | Gluthatione-S-transferase P1 polymorphism I105V in familial and sporadic prostate cancer. | Cancer Genet Cytogenet | |
| JD Debes, A Yokomizo, SK McDonnell, SJ Hebbring, GB Christensen, JM Cunningham, SJ Jacobsen, DJ Tindall, W Liu, DJ Schaid, SN Thibodeau, | ||||||||
| Several reports suggest that the glutathione-S-transferase (GST) family of enzymes is involved in a variety of cancers, due to their carcinogen-detoxification properties. A polymorphism in codon 105 of the pi variant (GSTP1 I105V), which affects the enzymatic activity of the enzyme, has been linked to the incidence of cancers from different organs. However, the published data in prostate cancer (PCa) is controversial. Some studies report an association with the GSTP1 I105V polymorphism and sporadic PCa, whereas other studies report no association. Recently, one study showed a positive correlation between the GSTP1 I105V polymorphism and familial PCa in a Japanese population. In the present study, we assessed the correlation of the GSTP1 I105V polymorphism with familial and sporadic PCa in an American population. We analyzed DNA samples from 438 patients with familial PCa, 499 patients with sporadic PCa, and 510 controls. We found no significant association between the GSTP1 I105V polymorphism and familial or sporadic PCa when compared to the control group [odds ratio (OR) =1.0 (0.74-1.37); P=0.58]. Moreover, no association was found after stratification for age of diagnosis, Gleason grade, or lymph node involvement [OR =0.84 (0.65-1.09), P=0.37]. These data indicate that there is no associated risk for sporadic or familial PCa in American families containing the GSTP1 I105V polymorphism. | ||||||||
| 1125 | 34.59 | 15814628 | 2005.08.08 | + | + | Nuclear factor-kappaB activation correlates with better prognosis and Akt activation in human gastric cancer. | Clin Cancer Res | |
| BL Lee, HS Lee, J Jung, SJ Cho, HY Chung, WH Kim, YW Jin, CS Kim, SY Nam, | ||||||||
| PURPOSE: Because the biological significance of constitutive nuclear factor-kappaB (NF-kappaB) activation in human gastric cancer is unclear, we undertook this study to clarify the regulatory mechanism of NF-kappaB activation and its clinical significance. EXPERIMENTAL DESIGN: Immunohistochemistry for NF-kappaB/RelA was done on 290 human gastric carcinoma specimens placed on tissue array slides. The correlations between NF-kappaB activation and clinicopathologic features, prognosis, Akt activation, tumor suppressor gene expression, or Bcl-2 expression were analyzed. We also did luciferase reporter assay, Western blot analysis, and reverse transcription-PCR using the SNU-216 human gastric cancer cell line transduced with retroviral vectors containing constitutively active Akt or the NF-kappaB repressor mutant of IkappaBalpha. RESULTS: Nuclear expression of RelA was found in 18% of the gastric carcinomas and was higher in early-stage pathologic tumor-node-metastasis (P = 0.019). A negative correlation was observed between NF-kappaB activation and lymphatic invasion (P = 0.034) and a positive correlation between NF-kappaB activation and overall survival rate of gastric cancer patients (P = 0.0228). In addition, NF-kappaB activation was positively correlated with pAkt (P = 0.047), p16 (P = 0.004), adenomatous polyposis coli (P < 0.001), Smad4 (P = 0.002), and kangai 1 (P < 0.001) expression. An in vitro study showed that NF-kappaB activity in gastric cancer cells is controlled by and controls Akt. CONCLUSIONS: NF-kappaB activation was frequently observed in early-stage gastric carcinoma and was significantly correlated with better prognosis and Akt activation. These findings suggest that NF-kappaB activation is a valuable prognostic variable in gastric carcinoma. | ||||||||
| 1126 | 34.58 | 7935325 | 1994.11.10 | + | + | Genetic analysis of the Chinese cytochrome P4502D locus: characterization of variant CYP2D6 genes present in subjects with diminished capacity for debrisoquine hydroxylation. | Mol Pharmacol | |
| I Johansson, M Oscarson, QY Yue, L Bertilsson, F Sjöqvist, M Ingelman-Sundberg, | ||||||||
| Cytochrome P4502D6 (CYP2D6) catalyzes the oxidative metabolism of several clinically important classes of drugs. Many of these have lower metabolic clearance rates among Chinese, compared with Caucasians, and are prescribed at lower doses for Asian patients. We have now evaluated the molecular genetic basis for this interethnic difference in drug metabolism. The CYP2D loci from two Chinese subjects, one homozygous for the XbaI 44-kilobase haplotype and one homozygous for the XbaI 29-kilobase haplotype, were cloned and characterized. Sequence analysis revealed two variant CYP2D6 genes, CYP2D6Ch1 and CYP2D6Ch2, having mutations yielding two and eight amino acid substitutions, respectively. Exon 9 of the CYP2D6Ch2 gene contained a sequence of 49 bases originating from the pseudogene CYP2D7P. In addition, mutations in the 5' flanking region common to both CYP2D6Ch genes were found. To evaluate the origin of the detrimental mutation in the genes, parts of the 5' flanking regions were introduced into a Hep G2/simian virus 40 expression system with chloramphenicol acetyltransferase as a reporter gene, and transfected cells were analyzed for activity. The ability of the upstream regions to bind nuclear factors was also evaluated using gel-shift analysis. Furthermore, several chimeric constructs of the CYP2D6wt and CYP2D6Ch genes were made, inserted into pCMV2 vectors, and expressed in COS-1 cells. A part of the upstream region of base pairs -1407 to -1068 was found to constitute an enhancer element, but the CYP2D6Ch-specific mutations did not influence the chloramphenicol acetyltransferase activity in the expression system. In contrast, expression of the chimeric genes revealed that the detrimental mutation of the CYP2D6Ch genes was C188-->T, causing a Pro34-->Ser amino acid substitution in a region that is a highly conserved in cytochromes P450 belonging to gene families 1 and 2. This substitution caused expression of a more unstable gene product, as evident from comparison of the relative levels of CYP2D6 mRNA, CYP2D6 protein, and bufuralol 1'-hydroxylase activities in pCMV2-CYP2D6-transfected COS-1 cells. Allele-specific polymerase chain reaction analysis of genomic DNA from 90 Chinese individuals revealed that the CYP2D6Ch1 allele was the most common one and its distribution correlated well with a higher metabolic ratio for debrisoquine. These data demonstrate that important interethnic differences exist in the structure of the CYP2D locus, and they suggest that the frequent distribution of the C188-->T mutation among the CYP2D6Ch genes explains the lower capacity among Chinese to metabolize drugs that are substrates of CYP2D6, such as antidepressants and neuroleptic agents. | ||||||||
| 1127 | 34.58 | 12456801 | 2003.06.09 | + | + | Interaction of early growth response protein 1 (Egr-1), specificity protein 1 (Sp1), and cyclic adenosine 3'5'-monophosphate response element binding protein (CREB) at a proximal response element is critical for gastrin-dependent activation of the chromogranin A promoter. | Mol Endocrinol | |
| R Raychowdhury, G Schäfer, J Fleming, S Rosewicz, B Wiedenmann, TC Wang, M Höcker, | ||||||||
| Recently, binding of specific protein 1 (Sp1) and cAMP response element binding protein (CREB) to a GC-rich element at -92/-62 has been identified as a critical step in gastrin-dependent regulation of the chromogranin A (CgA) gene in gastric epithelial cells. Here we demonstrate that binding of early growth response protein 1 (Egr-1) to the distal part of the -92/-62 site is also required for gastrin-dependent CgA transactivation. Gastrin elevated cellular and nuclear Egr-1 levels in a time-dependent manner and also increased Egr-1 binding to the CgA -92/-73 region. Disruption of this site reduced gastrin responsiveness without influencing basal promoter activity, while loss of Sp1 and/or CREB binding sites diminished basal and gastrin-stimulated CgA promoter activity. Ectopic Egr-1 overexpression potently stimulated the CgA promoter, whereas coexpression of Egr-1 with Sp1 and/or CREB resulted in additive effects. Functional analysis of Sp1-, Egr-1-, or CREB-specific promoter mutations in transfection studies confirmed the tripartite organization of the CgA -92/-62 element. Signaling studies revealed that MAPK kinase 1 (MEK1)/ERK1/2 cascades are critical for gastrin-dependent Egr-1 protein accumulation as well as Egr-1 binding to the CgA promoter. Our studies for the first time identify Egr-1 as a nuclear target of gastrin and show that functional interplay of Egr-1, Sp1, and CREB is indispensable for gastrin-dependent CgA transactivation in gastric epithelial cells. | ||||||||
| 1128 | 34.58 | 17470695 | 2007.06.07 | + | + | Clinical aspects of type-1 long-QT syndrome by location, coding type, and biophysical function of mutations involving the KCNQ1 gene. | Circulation | |
| AJ Moss, W Shimizu, AA Wilde, JA Towbin, W Zareba, JL Robinson, M Qi, GM Vincent, MJ Ackerman, ES Kaufman, N Hofman, R Seth, S Kamakura, Y Miyamoto, I Goldenberg, ML Andrews, S McNitt, | ||||||||
| BACKGROUND: Type-1 long-QT syndrome (LQTS) is caused by loss-of-function mutations in the KCNQ1-encoded I(Ks) cardiac potassium channel. We evaluated the effect of location, coding type, and biophysical function of KCNQ1 mutations on the clinical phenotype of this disorder. METHODS AND RESULTS: We investigated the clinical course in 600 patients with 77 different KCNQ1 mutations in 101 proband-identified families derived from the US portion of the International LQTS Registry (n=425), the Netherlands' LQTS Registry (n=93), and the Japanese LQTS Registry (n=82). The Cox proportional hazards survivorship model was used to evaluate the independent contribution of clinical and genetic factors to the first occurrence of time-dependent cardiac events from birth through age 40 years. The clinical characteristics, distribution of mutations, and overall outcome event rates were similar in patients enrolled from the 3 geographic regions. Biophysical function of the mutations was categorized according to dominant-negative (> 50%) or haploinsufficiency (< or = 50%) reduction in cardiac repolarizing I(Ks) potassium channel current. Patients with transmembrane versus C-terminus mutations (hazard ratio, 2.06; P<0.001) and those with mutations having dominant-negative versus haploinsufficiency ion channel effects (hazard ratio, 2.26; P<0.001) were at increased risk for cardiac events, and these genetic risks were independent of traditional clinical risk factors. CONCLUSIONS: This genotype-phenotype study indicates that in type-1 LQTS, mutations located in the transmembrane portion of the ion channel protein and the degree of ion channel dysfunction caused by the mutations are important independent risk factors influencing the clinical course of this disorder. | ||||||||
| 1129 | 34.58 | 15728438 | 2005.07.12 | + | + | Evidence for a combined genetic effect of the 5-HT(1A) receptor and serotonin transporter genes in the clinical outcome of major depressive patients treated with citalopram. | J Psychopharmacol | |
| B Arias, R Catalán, C Gastó, B Gutiérrez, L Fañanás, | ||||||||
| In the context of a long-term follow-up study, we analysed the possible implication of the 5-HT(1A) receptor gene (HTR1A) -1018C/G polymorphism in the clinical outcome of major depressive patients treated with citalopram. We had previously reported an association between variation on the SERT gene (SLC6A4) and clinical remission after citalopram treatment. In the present 12-week follow-up study, the combined effect of HTR1A and SLC6A4 genes in clinical outcome and response to citalopram was also evaluated. The sample consisted of 130 patients, all of Spanish origin, who were diagnosed as having a current major depressive episode according to DSM-IV criteria. A 21-item Hamilton Depression Rating Scale was used to assess severity of symptoms at the beginning and during the follow-up to determine the outcome and remission status at week 12. Patients were genotyped for HTR1A gene and, in addition, for two polymorphisms at the CYP2C19 gene, which together account for the 87% of the Caucasian poor metabolizer phenotype. Data were analysed adjusting for the effect of poor metabolizers in clinical response. No independent effect was found for the 5-HT(1A) receptor gene in relation to clinical outcome or remission after citalopram treatment. However, a combined genetic effect of HTR1A and SLC6A4 genes was found to influence the clinical outcome of patients [F(4,102) = 2.89, p= 0.02]. When considering the remission status, an increase of patients carrying the risk genotype combination (S/S-G/G) was found among those subjects who did not reach remission (Fisher's exact test = 0.009). Our results suggest that the combined effect of the serotonin transporter and the 5-HT(1A) receptor genes could be related to the clinical outcome of depressive patients treated with citalopram. | ||||||||
| 1130 | 34.57 | 8892022 | 1997.03.03 | + | + | A point mutation in an invariant splice donor site leads to exon skipping in two unrelated Dutch patients with dihydropyrimidine dehydrogenase deficiency. | J Inherit Metab Dis | |
| P Vreken, AB Van Kuilenburg, R Meinsma, GP Smit, HD Bakker, RA De Abreu, AH van Gennip, | ||||||||
| Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disease characterized by thymine-uraciluria and associated with a variable clinical phenotype. In order to identify the molecular defect underlying complete DPD deficiency in a Dutch patient previously shown to have a 165 base pair deletion in the mature DPD mRNA, we cloned the genomic region encompassing the skipped exon and its flanking intron sequences. Sequence analysis revealed that the patient was homozygous for a single G-->A point mutation in the invariant GT dinucleotide splice donor site downstream of the skipped exon. The same mutation was identified in another, unrelated, Dutch patient. Because this mutation destroys a unique MaeII restriction site, rapid screening using restriction enzyme cleavage of the amplified genomic region encompassing this mutation is possible. Analysis of 50 controls revealed no individuals heterozygous for this mutation. | ||||||||
| 1131 | 34.57 | 16272956 | 2006.03.01 | + | + | CYP2A6, MAOA, DBH, DRD4, and 5HT2A genotypes, smoking behaviour and cotinine levels in 1518 UK adolescents. | Pharmacogenet Genomics | |
| S Huang, DG Cook, LJ Hinks, XH Chen, S Ye, JA Gilg, MJ Jarvis, PH Whincup, IN Day, | ||||||||
| OBJECTIVES: Smoking is a major cause of death and often initiates in adolescence. Mutations in CYP2A6 slow metabolism of nicotine to cotinine. Haploinsufficiency in adults is associated with lower cigarette consumption, lower cotinine level and higher quit rates. Other genes are also implicated in smoking behaviour. We explored smoking behaviour and cotinine levels in relation to genotypes in adolescents. METHODS: 1518 subjects from the Ten Towns Heart Health Study were genotyped for CYP2A6 alleles *1A, *1B, *2, *4, *5, *9 and *12 to classify predicted nicotine metabolism rate. DBH(rs77905), MAOA(rs1801291+VNTR), DRD4(VNTR) and 5HT2A(rs6313) were also studied. Smoking status was established by questionnaire and salivary cotinine measurement at 13-15 and 18 years. RESULTS: No significant associations were identified for DBH, MAOA, DRD4 and 5HT2A markers, with smoking status or cotinine level at either age. At age 18, haploinsufficiency (HI) for CYP2A6 was associated with a higher odds of being a current smoker compared with the *1B carriers (WT1B) (OR = 2.23 (1.16, 4.27) for current versus ex); *1A homozygotes (WT1A) were also at slightly higher risk (OR = 1.44 (1.01, 2.06)). Partial haploinsufficiency (PHI) was not associated with being a current smoker. There were no significant associations at age 13-15. PHI and HI were associated with higher cotinine levels amongst smokers at both 13-15 and at 18 years compared with WT1B and WT1A groups. CONCLUSIONS: CYP2A6 haploinsufficiency increases likelihood of continuing smoking in teenagers. We hypothesize an explanatory 'occupancy' model to explain why haploinsufficiency results in faster progression to nicotine dependence, but lower subsequent consumption. | ||||||||
| 1132 | 34.56 | 12476327 | 2003.07.08 | + | + | Association study of the serotonin transporter promoter polymorphism and symptomatology and antidepressant response in major depressive disorders. | Mol Psychiatry | |
| YW Yu, SJ Tsai, TJ Chen, CH Lin, CJ Hong, | ||||||||
| The serotonin transporter (5-HTT) is the site of primary action for the selective serotonin reuptake inhibitors (SSRIs). Previous Western reports have demonstrated that the lallele of the 5-HTT gene-linked polymorphic-region (5-HTTLPR) polymorphism is associated with better SSRI antidepressive effects than the s allele, however, another study of a Korean population has produced a contrasting finding. The present study tested the hypothesis that the 5-HTTLPR genetic polymorphism is associated with SSRI antidepressant response by evaluating total and cluster depressive symptoms for 121 Chinese patients diagnosed with major depression. Analysis of the results reveals that patients with the l/l genotype had a significantly better response to SSRI (fluoxetine) when compared with s allele carriers, as evaluated on the basis of total (P = 0.013), core (P = 0.011), and psychic-anxiety (P = 0.005) and somatic-anxiety (P = 0.002) Hamilton Depression Rating Scale-score percentage change. Our findings confirm reports that the l allele is associated with better SSRI response. | ||||||||
| 1133 | 34.56 | 9799083 | 1998.11.19 | + | + | Genomic organization and mutational analysis of KVLQT1, a gene responsible for familial long QT syndrome. | Hum Genet | |
| T Itoh, T Tanaka, R Nagai, K Kikuchi, S Ogawa, S Okada, S Yamagata, K Yano, Y Yazaki, Y Nakamura, | ||||||||
| To elucidate the role of the KVLQT1 gene in the pathogenesis of long QT syndrome (LQTS), we have established a screening system for detecting KVLQT1 mutations by the polymerase chain reaction-single strand conformation polymorphism technique (PCR-SSCP). We first determined exon/intron boundaries and flanking intronic sequences, and found that the KVLQT1 gene consists of 17 coding exons. Subsequently, we synthesized oligonucleotide primers to cover the coding region and the flanking intronic sequences, and searched for mutations in 31 Japanese LQTS families. When genomic DNA from each proband was examined by PCR-SSCP followed by direct DNA sequencing, mutations were detected in five families; two independent families carried the same mutation and three of the four were novel. Each mutation was present in affected relatives of the respective proband. This work will enable us to search more thoroughly for LQTS mutations associated with KVLQT1, and eventually will help us in finding genotype/phenotype relationships. | ||||||||
| 1134 | 34.56 | 15723830 | 2005.06.21 | + | + | Identification of protein kinase A catalytic subunit beta as a novel binding partner of p73 and regulation of p73 function. | J Biol Chem | |
| T Hanamoto, T Ozaki, K Furuya, M Hosoda, S Hayashi, M Nakanishi, H Yamamoto, H Kikuchi, S Todo, A Nakagawara, | ||||||||
| Post-translational modifications play a crucial role in regulation of the protein stability and pro-apoptotic function of p53 as well as its close relative p73. Using a yeast two-hybrid screening based on the Sos recruitment system, we identified protein kinase A catalytic subunit beta (PKA-Cbeta) as a novel binding partner of p73. Co-immunoprecipitation and glutathione S-transferase pull-down assays revealed that p73alpha associated with PKA-Cbeta in mammalian cells and that their interaction was mediated by both the N- and C-terminal regions of p73alpha. In contrast, p53 failed to bind to PKA-Cbeta. In vitro phosphorylation assay demonstrated that glutathione S-transferase-p73alpha-(1-130), which has one putative PKA phosphorylation site, was phosphorylated by PKA. Enforced expression of PKA-Cbeta resulted in significant inhibition of the transactivation function and pro-apoptotic activity of p73alpha, whereas a kinase-deficient mutant of PKA-Cbeta had no detectable effect. Consistent with this notion, treatment with H-89 (an ATP analog that functions as a PKA inhibitor) reversed the dibutyryl cAMP-mediated inhibition of p73alpha. Of particular interest, PKA-Cbeta facilitated the intramolecular interaction of p73alpha, thereby masking the N-terminal transactivation domain with the C-terminal inhibitory domain. Thus, our findings indicate a PKA-Cbeta-mediated inhibitory mechanism of p73 function. | ||||||||
| 1135 | 34.55 | 7927337 | 1994.11.09 | + | + | DNA haplotype-dependent differences in the amino acid sequence of debrisoquine 4-hydroxylase (CYP2D6): evidence for two major allozymes in extensive metabolisers. | Hum Genet | |
| S Panserat, C Mura, N Gérard, M Vincent-Viry, MM Galteau, E Jacqz-Aigrain, R Krishnamoorthy, | ||||||||
| The molecular basis for DNA haplotype-dependent debrisoquine 4-hydroxylase (CYP2D6) expression was explored by sequencing all of the nine exons of the CYP2D6 gene. Two distinct exon sequence frameworks of the CYP2D6 gene were found, each associated with specific BamHI-defined DNA haplotypes of the CYP2D cluster. They corresponded to Arg296/Cys296 and Ser486/Thr486 amino acid polymorphisms in the CYP2D6 enzyme, and occurred in almost equal frequency among the Caucasians examined. These two major allozymes with amino acid differences in the presumed substrate recognition region and in the vicinity of the heme binding site could be the source of the observed DNA haplotype-dependent variation in phenotypic expression. | ||||||||
| 1136 | 34.54 | 10668854 | 2000.02.22 | + | + | Deficient cotinine formation from nicotine is attributed to the whole deletion of the CYP2A6 gene in humans. | Clin Pharmacol Ther | |
| M Nakajima, S Yamagishi, H Yamamoto, T Yamamoto, Y Kuroiwa, T Yokoi, | ||||||||
| Nicotine is mainly metabolized to cotinine by cytochrome P450 (CYP) 2A6. Large interindividual differences in nicotine metabolism have been reported in humans. The purpose of this study was to clarify the relationship between the poor metabolism of nicotine and the existence of the CgammaP2A6v1 and CgammaP2A6v2 alleles, and a whole deletion allele of the CgammaP2A6 gene. The plasma concentrations of nicotine and cotinine were measured in 10 healthy subjects after each smoked one cigarette or chewed one piece of nicotine gum. One subject showed no detectable cotinine level in plasma when smoking and the lowest cotinine level when receiving nicotine gum. The subject was regarded as a poor metabolizer of nicotine by a probit analysis and was found to carry a homozygous whole deletion allele of the CgammaP2A6 gene. This is the first report to show that deficient cotinine formation in humans is attributed to the whole deletion of the CgammaP2A6 gene. | ||||||||
| 1137 | 34.54 | 12172336 | 2002.09.18 | + | + | The impact of CYP2C19 and CYP2D6 genotypes on metabolism of amitriptyline in Japanese psychiatric patients. | J Clin Psychopharmacol | |
| K Shimoda, T Someya, A Yokono, S Morita, G Hirokane, S Takahashi, M Okawa, | ||||||||
| We investigated the effect of the CYP2C19 and CYP2D6 genotypes on the metabolism of amitriptyline (AT) in Japanese psychiatric patients. Steady-state concentrations of AT and its metabolites (nortriptyline [NT], trans-10-hydroxy-nortriptyline [EHNT], cis-10-hydroxy-nortriptyline [ZHNT], trans-10-hydroxy-amitriptyline [EHAT], and cis-10-hydroxy-amitriptyline [ZHAT]) in 50 patients were determined by high-performance liquid chromatography. Significantly higher plasma concentrations of AT corrected for dose and body weight in the subjects with two mutated alleles of CYP2C19 than in those with no mutated alleles of CYP2C19 were observed (no mutated alleles vs. two mutated alleles: 36.0 +/- 18.2 vs. 64.0 +/- 25.2 ng/mL/mg/kg, p = 0.025). A significantly higher AT/NT ratio was seen in the subjects with two mutated alleles of CYP2C19 than in those with no mutated alleles of CYP2C19 (no mutated alleles vs. two mutated alleles: 1.27 +/- 0.59 vs. 3.40 +/- 1.02, p = 0.001). A trend for higher NT/EHNT ratio in the subjects with two mutated alleles of CYP2D6 than in those with no mutated alleles of CYP2D6 was observed (no mutated alleles vs. two mutated alleles: 0.73 +/- 0.39 vs. 1.31 +/- 0.81, p = 0.068). A trend for higher plasma concentrations of total hydroxylated metabolites of AT (EHAT + ZHAT) corrected for dose and body weight in the subjects with two mutated alleles of CYP2C19 than in those with no mutated alleles of CYP2C19 was found (no mutated alleles vs. two mutated alleles: 9.5 +/- 5.8 vs. 17.8 +/- 8.9, p = 0.051). Therefore, the genotype of CYP2C19 is one of the important determinants of the plasma concentrations of AT and the capacity to desmethylate AT. Mother compound AT is shunted via hydroxylation pathways from AT to EHAT and ZHAT in the subjects with homozygotes of mutated alleles of CYP2C19 in order to compensate for the decreased capacity to desmethylate AT. | ||||||||
| 1138 | 34.53 | 12167562 | 2002.12.30 | + | + | Effects of bergamottin on human and monkey drug-metabolizing enzymes in primary cultured hepatocytes. | Drug Metab Dispos | |
| YH Wen, J Sahi, E Urda, S Kulkarni, K Rose, X Zheng, JF Sinclair, H Cai, SC Strom, VE Kostrubsky, | ||||||||
| We investigated the effect of bergamottin, a major furanocoumarin in grapefruit juice, on phase I and phase II drug-metabolizing enzymes using cultured human and monkey hepatocytes. Both cultured systems were compared and evaluated for the direct effects of bergamottin as well as control treatments on liver enzymes. Treatment of hepatocytes with 0.1, 1, 5, and 10 microM bergamottin resulted in a concentration-dependent reduction in CYP3A4 activity (40-100%) in both human and monkey cells, as measured by testosterone 6 beta-hydroxylase activity. Bergamottin was potent at eliciting these inhibitory effects at both basal and induced states of CYP3A. Bergamottin (5 microM) completely inhibited alpha-naphthoflavone-induced ethoxyresorufin O-dealkylase (EROD) and methoxyresorufin O-dealkylase (MROD) activities in human hepatocytes and caused a 100% decrease in EROD activity in monkey hepatocytes. A 48-h exposure of cultured human hepatocytes to bergamottin resulted in increased levels of immunoreactive CYP3A4, CYP1A1, and CYP1A2 proteins, and CYP3A4, CYP1A1, CYP1A2, CYP2B6, and UDP-glucuronosyl transferase mRNAs. There was only a 20 to 30% reduction in glucuronidation and sulfation of 4-methylumbelliferone in human hepatocytes by 10 microM bergamottin and no effect on conjugation in the monkey hepatocytes. These results suggest that bergamottin causes both inhibition of CYP3A and CYP1A1/2 enzymatic activities and induction of correspondent proteins and mRNAs. | ||||||||
| 1139 | 34.53 | 2879902 | 1987.02.27 | + | + | Characterization and inhibition of mephenytoin 4-hydroxylase activity in human liver microsomes. | J Pharmacol Exp Ther | |
| SD Hall, FP Guengerich, RA Branch, GR Wilkinson, | ||||||||
| The in vivo metabolism in humans of the anticonvulsant mephenytoin exhibits stereoselectivity as well as genetic polymorphism of the 4-hydroxylation pathway. The characteristics of the involved cytochrome P-450 isozyme are, however, not known completely. Accordingly, the ability of human liver microsomes to metabolize mephenytoin and its enantiomers was investigated in vitro, and the ability of related anticonvulsants and other compounds to inhibit 4-hydroxylation was studied. Marked stereoselectivity was observed in the conversion of S-mephenytoin to its 4-hydroxy metabolite, but N-demethylation was essentially similar for both enantiomers. The intrinsic clearance (Vmax/Km) for 4-hydroxymephenytoin formation showed an almost 10-fold range in five livers and was 150- to 1000-fold greater than that for N-demethylation. Competitive inhibition of 4-hydroxylation was observed with ethotoin, mephobarbital, methsuximide and phensuximide, but not other commonly used anticonvulsants such as ethosuximide, phenobarbital, phenytoin and primidone. However, synthetic N-alkyl analogs of the latter compounds were found to be inhibitory. An aryl residue alpha to the carbonyl carbon of an N-alkyl lactam in a 5- or 6-membered ring, therefore, appears to be a minimal requirement for strong interaction with the 4-hydroxylase. Warfarin, but not diazepam, ketoconazole or iodochlorohydroxyquin, were also competitive inhibitors, but at much higher concentrations than the anticonvulsants. Competitive inhibition at concentrations similar to the Km of 4-hydroxymephenytoin formation (30-350 microM) may indicate that the isozyme is involved in the metabolism of the substrates under consideration and, therefore, their in vivo metabolism may be regulated to some extent by the same genetic factor(s) that determine mephenytoin's biotransformation. | ||||||||
| 1140 | 34.53 | 11911968 | 2002.06.24 | + | + | Influence of cytochrome P450 CYP2C9 genotypes in lung cancer risk. | Cancer Lett | |
| E García-Martín, C Martínez, JM Ladero, FJ Gamito, A Rodriguez-Lescure, JA Agúndez, | ||||||||
| Cytochrome P-450 CYP2C9 enzyme is involved in the metabolism of xenobiotics and carcinogens. Variant alleles CYP2C9*2 and CYP2C9*3 encode enzymes with altered properties, and CYP2C9*2 has been related to lung cancer risk.The frequency of CYP2C9 variant alleles was analyzed in genomic DNA from 104 patients with lung cancer and in 197 healthy controls. No statistically significant differences in CYP2C9 genotypes, allele frequencies or predicted phenotypes were observed between overall patients and controls. Unconditional logistic regression for the interaction smoking/genotype indicate P values of 0.66 and 0.62 for carriers of CYP2C9*2 and CYP2C9*3, respectively, versus individuals without these mutations. The P values for the same interaction in carriers of one and two mutated genes were 0.56 and 0.67, respectively, versus individuals homozygous for non-mutated genes. Independent analyses of histological types of lung cancer also indicated the absence of statistically significant differences as compared to healthy subjects. Association between CYP2C9 polymorphism and lung cancer risk was not identified in this study. | ||||||||
| 1141 | 34.52 | 10471066 | 1999.10.14 | + | + | UDP-glucuronosyltransferase (UGT1A1*28 and UGT1A6*2) polymorphisms in Caucasians and Asians: relationships to serum bilirubin concentrations. | Pharmacogenetics | |
| JW Lampe, J Bigler, NK Horner, JD Potter, | ||||||||
| Polymorphisms that alter UDP-glucuronosyltransferase (UGT) activities have been identified. Mutations in the promoter of the UGT1A1 gene (UGT1A1*28), resulting in 5, 7 or 8, instead of 6 thymine-adenine (TA) repeats, alter bilirubin conjugation. Two missense mutations on one allele of UGT1A6 (UGT1A6*2) result in T181A and R184S amino acid substitutions and reduced activity against phenolics, such as 4-nitrophenol, 4-hydroxycoumarin and butylated hydroxy anisole. We determined the frequency of these polymorphisms in 245 healthy men and women, aged 20-40 years and examined the relationship between TA repeat number and serum bilirubin concentrations in a subset of 24 Asians and 169 Caucasians. The frequencies of the UGT1A1*28 genotypes were 0.537, 0.348, 0.098, 0.008 and 0.008 for promoter TA repeats 6/6, 6/7, 7/7, 5/6 and 6/8, respectively. Both allele and genotype frequencies varied by race (P < 0.02), with 11% of the Caucasians and none of the Asians having the 7/7 genotype. Within both ethnic groups, serum bilirubin increased with increased numbers of UGT1A1 promoter TA repeats (P = 0.0001). However, a strong ethnic group-by-UGT1A1 genotype interaction suggests that additional ethnic differences in bilirubin metabolism contribute to observed bilirubin concentrations. Genotype frequencies for UGT1A6*2 were 0.478, 0.392, 0.029, 0.090, 0.012 for wild-type (wt)/wt, wt/T181A + R184S, wt/R184S, T181A + R184S/T181A + R184S and T181A + R184S/R184S, respectively. The co-occurrence of polymorphisms in UGT1A1 and UGT1A6 differed from that expected (P < 0.0001): individuals homozygous wild-type for UGT1A1 and UGT1A6 were observed at twice the expected frequency; individuals homozygous variant for both genes were ten-fold more frequent and individuals homozygous wild-type for one gene and homozygous variant for the other were ten-fold less frequent than expected. Overall, 8% were homozygous variant for both UGT1 polymorphisms and 43% had at least one variant allele for both UGT1A1*28 and UGT1A6*2. These highly prevalent polymorphisms, which result in modified expression and activity of UGTs, may influence susceptibility to cancers associated with altered metabolism of endogenous and xenobiotic compounds. | ||||||||
| 1142 | 34.52 | 10577908 | 2000.01.27 | + | + | The molecular basis of Sjögren-Larsson syndrome: mutation analysis of the fatty aldehyde dehydrogenase gene. | Am J Hum Genet | |
| WB Rizzo, G Carney, Z Lin, | ||||||||
| Sjögren-Larsson syndrome (SLS) is an autosomal recessive disorder characterized by ichthyosis, mental retardation, spasticity, and deficient activity of fatty aldehyde dehydrogenase (FALDH). To define the molecular defects causing SLS, we performed mutation analysis of the FALDH gene in probands from 63 kindreds with SLS. Among these patients, 49 different mutations-including 10 deletions, 2 insertions, 22 amino acid substitutions, 3 nonsense mutations, 9 splice-site defects, and 3 complex mutations-were found. All of the patients with SLS were found to carry mutations. Nineteen of the missense mutations resulted in a severe reduction of FALDH enzyme catalytic activity when expressed in mammalian cells, but one mutation (798G-->C [K266N]) seemed to have a greater effect on mRNA stability. The splice-site mutations led to exon skipping or utilization of cryptic acceptor-splice sites. Thirty-seven mutations were private, and 12 mutations were seen in two or more probands of European or Middle Eastern descent. Four single-nucleotide polymorphisms (SNPs) were found in the FALDH gene. At least four of the common mutations (551C-->T, 682C-->T, 733G-->A, and 798+1delG) were associated with multiple SNP haplotypes, suggesting that these mutations originated independently on more than one occasion or were ancient SLS genes that had undergone intragenic recombination. Our results demonstrate that SLS is caused by a strikingly heterogeneous group of mutations in the FALDH gene and provide a framework for understanding the genetic basis of SLS and the development of DNA-based diagnostic tests. | ||||||||
| 1143 | 34.50 | 12970361 | 2004.01.12 | + | + | A transforming growth factor-beta control element required for SM alpha-actin expression in vivo also partially mediates GKLF-dependent transcriptional repression. | J Biol Chem | |
| Y Liu, S Sinha, G Owens, | ||||||||
| We previously demonstrated that a conserved transforming growth factor-beta control element (TCE) within the 5'-region of the smooth muscle cell (SMC) differentiation marker gene SM alpha-actin could mediate both transcriptional activation and repression in cultured SMCs through interaction with members of the zinc finger Kruppel-like transcription factor (KLF) family. The aims of the present studies were to: 1) determine the role of the SM alpha-actin TCE in vivo through mutagenesis studies in transgenic mice and 2) further characterize the possible role and mechanisms by which the TCE-binding factor GKLF/KLF4 induces repression of SMC marker genes in various SMC model systems in vitro. Our results showed that the TCE was required for SM alpha-actin promoter activity in transgenic mice in vivo. Results of transient transfection studies showed that GKLF-induced repression of a SM alpha-actin promoter/luciferase reporter gene partially depended on the TCE. Furthermore, a GKLF overexpressing adenovirus inhibited whereas GKLF morpholino antisense oligos increased expression of endogenous SMC marker genes. Results of chromatin immunoprecipitation assays showed GKLF binding to TCE containing regions of various SMC marker gene promoters within intact chromatin. Finally, results of co-transfection studies showed that overexpression of IKLF/KLF5 reversed GKLF-dependent repression thus supporting a model of reciprocal activation-repression of SMC gene expression by different members of the KLF gene family. | ||||||||
| 1144 | 34.50 | 8633005 | 1996.07.01 | + | + | P-glycoprotein: a major determinant of rifampicin-inducible expression of cytochrome P4503A in mice and humans. | Proc Natl Acad Sci U S A | |
| EG Schuetz, AH Schinkel, MV Relling, JD Schuetz, | ||||||||
| The P-glycoprotein (Pgp) efflux pump can influence the hepatocellular concentration of xenobiotics that are modulators and substrates of cytochrome P4503A (CYP3A). We tested the hypothesis that Pgp is a determinant of drug-inducible expression of CYP3A. The magnitude of CYP3A induction by rifampicin was compared in the human parental colon carcinoma cell line LS 180/WT (wild type) and in two derivative clones overexpressing the human multidrug resistance gene MDR1 (also designated PGY1) because of either drug selection (LS 180/ADR) or transfection with MDRI cDNA (LS 180/MDR). In both MDR1 cDNA-overexpressing clones, rifampicin induction of CYP3A mRNA and protein was decreased and required greater rifampicin concentrations compared with parental cells. The role of Pgp in regulation of CYP3A expression in vivo was analyzed in mice carrying a targeted disruption of the mdr1a mouse gene. Oral treatment with increasing doses of rifampicin resulted in elevated drug levels in the livers of mdr1a (-/-) mice compared with mdr1a (+/+) mice at all doses. Consistent with the enhanced accumulation of rifampicin in mdr1a (-/-) mice, lower doses of rifampicin were required for induction of CYP3A proteins, and the magnitude of CYP3A induction was greater at all doses of rifampicin in mdr1a (-/-) mice compared with mdr1a (+/+) mice. We conclude that Pgp-mediated transport is a critical element influencing the CYP3A inductive response. | ||||||||
| 1145 | 34.50 | 10022751 | 1999.04.13 | + | + | An additional defective allele, CYP2C19*5, contributes to the S-mephenytoin poor metabolizer phenotype in Caucasians. | Pharmacogenetics | |
| GC Ibeanu, J Blaisdell, BI Ghanayem, C Beyeler, S Benhamou, C Bouchardy, GR Wilkinson, P Dayer, AK Daly, JA Goldstein, | ||||||||
| The metabolism of the anticonvulsant drug mephenytoin exhibits a genetic polymorphism in humans. This polymorphism exhibits marked racial heterogeneity, with the poor metabolizer PM phenotype representing 13-23% of oriental populations, but only 2-5% of Caucasian populations. Two defective CYP2C19 alleles (CYP2C19*2 and CYP2C19*3) have been described, which account for more than 99% of Oriental poor metabolizer alleles but only approximately 87% of Caucasian poor metabolizer alleles. Therefore, additional defects presumably contribute to the poor metabolizer in Caucasians. Recent studies have found a third mutation CYP2C19*4, which accounts for approximately 3% of Caucasian poor metabolizer alleles. A fourth rare mutation (CYP2C19*5A) (C99,A991,Ile331;C1297T,Arg433-->Trp) resulting in an Arg433 to Trp substitution in the heme-binding region has been reported in a single Chinese poor metaboliser outlier belonging to the Bai ethnic group. The present study identifies a second variant allele CYP2C19*5B (C99-->T; A991-->G, Ile331-->Val; C1297-T, Arg433-->Trp in one of 37 Caucasian poor metabolizers. The frequency of the CYP2C19*5 alleles is low in Chinese (approximately 0.25% in the Bai ethnic group) and Caucasians (< 0.9%). However, these alleles contribute to the poor metabolizer phenotype in both ethnic groups and increases the sensitivity of the genetic tests for identifying defective alleles to approximately 100% in Chinese poor metabolizers and 92% in Caucasian poor metabolizers genotyped in our laboratory. The Arg433 to Trp mutation in the heme-binding region essentially abolishes activity of recombinant CYP2C19*5A toward S-mephenytoin and tolbutamide, which is consistent with the conclusion that CYP2C19*5 represents poor metabolizer alleles. | ||||||||
| 1146 | 34.48 | 12386136 | 2003.05.07 | + | + | Effects of fibrates on metabolism of statins in human hepatocytes. | Drug Metab Dispos | |
| T Prueksaritanont, C Tang, Y Qiu, L Mu, R Subramanian, JH Lin, | ||||||||
| This study investigated the metabolic interaction between fibrates and statin hydroxy acids in human hepatocytes. Gemfibrozil (GFZ) modestly affected the formation of beta-oxidative products and CYP3A4-mediated oxidative metabolites of simvastatin hydroxy acid (SVA) but markedly inhibited the glucuronidation-mediated lactonization of SVA and the glucuronidation of a beta-oxidation product (IC(50) approximately 50 and 15 microM, respectively). In contrast, fenofibrate had a minimal effect on all the metabolic pathways of SVA. GFZ also significantly inhibited (IC(50) approximately 50-60 microM) the oxidation of cerivastatin (CVA) and rosuvastatin (RVA), but not of atorvastatin (AVA), while effectively decreasing (IC(50) approximately 30 to 60 microM) the lactonization of all three statins. As was observed previously with other statin hydroxy acids, RVA underwent significant glucuronidation to form an acyl glucuronide conjugate and lactonization to form RVA lactone in human liver microsomes and by UGT 1A1 and 1A3. While GFZ is not an inhibitor of CYP3A4, it is a competitive inhibitor (K(i) = 87 microM) of CYP2C8, a major catalyzing enzyme for CVA oxidation. These results suggest that 1) the pharmacokinetic interaction observed between GFZ and statins was not likely mediated by the inhibitory effect of GFZ on the beta-oxidation, but rather by its effect primarily on the glucuronidation and non-CYP3A-mediated oxidation of statin hydroxy acids, and 2) there is a potential difference between fibrates in their ability to affect the pharmacokinetics of statins, and among statins in their susceptibility to metabolic interactions with GFZ in humans. | ||||||||
| 1147 | 34.48 | 11702058 | 2002.05.02 | + | + | 5-HT2A promoter polymorphism is not associated with anorexia nervosa in Japanese patients. | Psychiatr Genet | |
| T Ando, G Komaki, M Karibe, N Kawamura, S Hara, M Takii, T Naruo, N Kurokawa, M Takei, N Tatsuta, M Ohba, S Nozoe, C Kubo, T Ishikawa, | ||||||||
| Genetic factors have been implicated in playing a significant role in susceptibility to anorexia nervosa (AN). Among many candidate genes for AN, an association with the A allele of the -1438G/A polymorphism in the promoter region of the 5-HT2A receptor has been reported. However, these findings are controversial and all patients studied to date have been Caucasian. This study was designed to determine whether this association is reproducible in Japanese subjects. This case-control study of a cohort of 75 female Japanese AN sufferers and 127 normal female control subjects revealed no significant association between the 5-HT2A promoter polymorphism and AN. Thus, at least for Japanese subjects, the A-allele of the -1438G/A polymorphism in the promoter region of the 5-HT2A receptor gene does not contribute to a predisposition to AN. | ||||||||
| 1148 | 34.47 | 12063562 | 2002.12.02 | + | + | Beta-adrenergic and arachidonic acid-mediated growth regulation of human breast cancer cell lines. | Int J Oncol | |
| Y Cakir, HK Plummer, PK Tithof, HM Schuller, | ||||||||
| Adenocarcinoma of the mammary gland is the leading type of cancer in women. Among these breast cancers those that are estrogen-responsive respond well to existing therapeutic regimens while estrogen non-responsive cancers metastasize widely, demonstrate a high relapse rate, and respond poorly to therapy. Over-expression of the arachidonic acid-metabolizing enzymes cyclooxygenase-2 and lypoxygenases is frequently observed in breast cancer, particularly the non-estrogen-responsive type, suggesting a role of the arachidonic acid (AA) cascade in the growth regulation of these malignancies. Adenocarcinomas of the lungs, pancreas and colon also frequently over-express AA-metabolizing enzymes, and recent evidence suggests that the growth-regulating AA-cascade in these malignancies is under beta-adrenergic control. Our current experiments have therefore tested the hypothesis that in analogy to these findings adenocarcinomas of the breast are also regulated by beta-adrenergic receptors via stimulation of the AA-cascade. Analysis of DNA synthesis by [3H]-thymidine incorporation assays in three estrogen-responsive and three estrogen non-responsive cell lines derived from human breast cancers demonstrated a significant reduction in DNA synthesis by beta-blockers and inhibitors of cyclooxygenase or lipoxygenases in all cell lines. Analysis of AA-release in one of the most responsive cell lines demonstrated a time-dependent increase in AA-release in response to the beta-adrenergic agonist isoproterenol. Analysis by RT-PCR revealed expression of beta2-adrenergic receptors in all cell lines whereas beta1-adrenergic receptors were not found in two of the estrogen non-responsive cell lines. Our data suggest that a significant subset of human breast cancers is under control of beta-adrenergic receptors via stimulation of the AA-cascade. These findings open up novel avenues for the prevention and clinical management of breast cancer, particularly the non-estrogen-responsive types. Moreover, our findings suggest that cardiovascular disease and adenocarcinomas in a variety of organ systems, including the breast may share common risk factors and benefit from similar preventive and treatment strategies. | ||||||||
| 1149 | 34.46 | 11240980 | 2001.04.05 | + | + | Effect of genotypic differences in CYP2C19 on cure rates for Helicobacter pylori infection by triple therapy with a proton pump inhibitor, amoxicillin, and clarithromycin. | Clin Pharmacol Ther | |
| T Furuta, N Shirai, M Takashima, F Xiao, H Hanai, H Sugimura, K Ohashi, T Ishizaki, E Kaneko, | ||||||||
| BACKGROUND: Proton pump inhibitors such as omeprazole and lansoprazole are mainly metabolized by CYP2C19 in the liver. The therapeutic effects of proton pump inhibitors are assumed to depend on CYP2C19 genotype status. OBJECTIVE: We investigated whether CYP2C19 genotype status was related to eradication rates of H pylori by triple proton pump inhibitor-clarithromycin-amoxicillin (INN, amoxicilline) therapy and attempted to establish a strategy for treatment after failure to eradicate H pylori. METHODS: A total of 261 patients infected with H pylori completed initial treatment with 20 mg of omeprazole or 30 mg of lansoprazole twice a day, 200 mg of clarithromycin three times a day, and 500 mg of amoxicillin three times a day for 1 week. CYP2C19 genotypes of patients were determined with polymerase chain reaction-restriction fragment length polymorphism analysis. Patients without eradication after initial treatment were retreated with 30 mg of lansoprazole four times daily and 500 mg of amoxicillin four times daily for 2 weeks. RESULTS: Eradication rates for H pylori were 72.7% (95% confidence interval, 64.4%-81.8%), 92.1% (confidence interval, 86.4%-97.3%), and 97.8% (confidence interval, 88.5%-99.9%) in the homozygous extensive, heterozygous extensive, and poor metabolizer groups, respectively. Thirty-four of 35 patients without eradication had an extensive metabolizer genotype of CYP2C19. Nineteen of those patients were infected with clarithromycin-resistant strains of H pylori. However, there were no amoxicillin-resistant strains of H pylori. Re-treatment of H pylori infection with dual high-dose lansoprazole-amoxicillin therapy succeeded in 30 of 31 patients with extensive metabolizer genotype of CYP2C19. CONCLUSION: The majority of patients without initial eradication of H pylori had an extensive metabolizer CYP2C19 genotype but were successfully re-treated with high doses of lansoprazole and an antibiotic to which H pylori was sensitive, such as amoxicillin, even when the patients were infected with clarithromycin-resistant strains of H pylori. | ||||||||
| 1150 | 34.46 | 15054565 | 2004.12.17 | + | + | Identification of cytochromes P450 2C9 and 3A4 as the major catalysts of phenprocoumon hydroxylation in vitro. | Eur J Clin Pharmacol | |
| M Ufer, JO Svensson, KW Krausz, HV Gelboin, A Rane, G Tybring, | ||||||||
| OBJECTIVE: This in-vitro study aimed at an identification of cytochrome P(450) (CYP) enzymes catalysing the (S)- and (R)-hydroxylation of the widely used anticoagulant phenprocoumon (PPC) to its major, inactive metabolites. METHODS: Relevant catalysts were identified by kinetic, correlation and inhibition experiments using human liver microsomes and recombinant enzymes. RESULTS: Kinetics revealed (S)-7-hydroxylation as quantitatively most important. Biphasic Eadie-Hofstee plots indicated more than one catalyst for the 4'-, 6- and 7-hydroxylation of both enantiomers with mean K(m1) and K(m2) of 144.5+/-34.9 and 10.0+/-6.49 microM, respectively. PPC hydroxylation rates were significantly correlated with CYP2C9 and CYP3A4 activity and expression analysing 11 different CYP-specific probes. Complete inhibition of PPC hydroxylation was achieved by combined addition of the CYP3A4-specific inhibitor triacetyloleandomycin (TAO) and a monoclonal, inhibitory antibody (mAb) directed against CYP2C8, 9, 18 and 19, except for the (R)-4'-hydroxylation that was, however, inhibited by ~80% using TAO alone. (S)-PPC hydroxylation was reduced by approximately 2/3 and approximately 1/3 using mAb2C8-9-18-19 and TAO, respectively, but (R)-6- and 7-hydroxylation by approximately 50% each. Experiments with mAbs directed against single CYP2C enzymes clearly indicated CYP2C9 as a major catalyst of the 6- and 7-hydroxylation for both enantiomers. However, CYP2C8 was equally important regarding the (S)-4'-hydroxylation. Recombinant CYP2C8 and CYP2C9 were high-affinity catalysts (K(m) <5 microM), whereas CYP3A4 operated with low affinity (K(m) >100 microM). CONCLUSION: CYP2C9 and CYP3A4 are major catalysts of (S)- and (R)-PPC hydroxylation, while CYP2C8 partly catalysed the (S)-4'-hydroxylation. Increased vigilance is warranted when PPC treatment is combined with substrates, inhibitors, or inducers of these enzymes. | ||||||||
| 1151 | 34.45 | 12442279 | 2002.12.23 | + | + | A double mutant [N543H+2393del9] allele in the LDL receptor gene in familial hypercholesterolemia: effect on plasma cholesterol levels and cardiovascular disease. | Hum Mutat | |
| S Castillo, G Reyes, D Tejedor, P Mozas, Y Suarez, MA Lasuncion, A Cenarro, F Civeira, R Alonso, P Mata, M Pocovi, | ||||||||
| Familial hypercholesterolemia is a genetic disorder caused by mutations in the LDL receptor gene. During a survey of mutations of LDL receptor gene in Spanish FH patients we found two mutations in the same allele: a missense N543H mutation in exon 11 and a 9bp inframe deletion (2393del9) located in exon 17. This double mutant allele was founded in 10 out of 458 unrelated patients: one homozygous FH [N543H+2393del9] + [N543H+2393del9], one compound heterozygote [N543H+2393del9] + [W-18X+E256K] and 8 heterozygotes. Flow cytometric analysis showed a defective LDL binding (20% of normal value) and internalization (23%) in lymphocytes from the homozygous patient; furthermore, studies of mitogen-stimulated lymphocytes demonstrated that the ability of LDL to support cell proliferation was impaired. Unexpectedly, not all carriers of the double mutant allele develop hypercholesterolemia and, furthermore, cholesterol-lowering treatment of the homozygous patient resulted in a 58% LDL cholesterol reduction. In conclusion, the phenotypic expression in the homozygous and heterozygous patients presented here, as well as the LDL-receptor residual activity, allowed the classification of this mutation as mild extending the group of mild mutations found at homozygosity. | ||||||||
| 1152 | 34.45 | 10385138 | 1999.07.29 | + | + | Genetic and dietary predictors of CYP2E1 activity: a phenotyping study in Hawaii Japanese using chlorzoxazone. | Cancer Epidemiol Biomarkers Prev | |
| LL Marchand, GR Wilkinson, LR Wilkens, | ||||||||
| Cytochrome P4502E1 (CYP2E1) is considered to play an important role in the metabolic activation of procarcinogens such as N-nitrosoamines and low molecular weight organic compounds. An RsaI polymorphism is present in the 5'-flanking region of the CYP2E1 gene, which could possibly affect its transcription. However, the relationship between genotype and the phenotypic catalytic activity of the enzyme has not been defined. Also, the effects in humans of specific dietary factors, other than ethanol, which have been shown in animal and in vitro studies to modulate CYP2E1 activity, are unknown. Accordingly, the CYP2E1-mediated metabolism of chlorzoxazone to its 6-hydroxy metabolite was investigated in 50 healthy Japanese of both sexes in Hawaii. The oral clearance of the in vivo probe, the trait measure of CYP2E1 activity, was smaller than that reported in European-Americans. Significantly, after adjustment for age and sex, the oral clearance of chlorzoxazone decreased with the number of variant c2 alleles, and its mean in the c2/c2 genotype (147 ml/min) was statistically lower (P < or = 0.05) than that for either the homozygous wild-type (238 ml/min) or the heterozygote (201 ml/min) genotypes. Stepwise multiple regression analysis indicated that body weight was a major contributor to the interindividual variability in the oral clearance of chlorzoxazone, accounting for 43% of the variance. Consumption of lettuce, broccoli, and black tea explained additional components of the variability (7, 5, and 6%, respectively), as did medication use (3%), age (4%), and CYP2E1 genotype (5%). Overall, 73% of the variance could be accounted for by these variables. Body weight, lettuce, and use of medications were associated with increased CYP2E1 activity, and the other covariates were associated with reduced enzyme function. Because of the role that CYP2E1 plays in procarcinogen activation, especially of N-nitrosamines involved in lung cancer, the identified factors may account in part for observed differences in individual susceptibility to disease and may also have implications for cancer prevention. | ||||||||
| 1153 | 34.44 | 9621515 | 1998.07.16 | + | + | Analysis of bilirubin uridine 5'-diphosphate (UDP)-glucuronosyltransferase gene mutations in seven patients with Crigler-Najjar syndrome type II. | J Hum Genet | |
| K Yamamoto, Y Soeda, T Kamisako, H Hosaka, M Fukano, H Sato, Y Fujiyama, Y Adachi, Y Satoh, T Bamba, | ||||||||
| Crigler-Najjar syndrome (CN) type II is caused by a reduction in hepatic bilirubin uridine 5'-diphosphate (UDP)-glucuronosyltransferase activity. Recently, there has been progress in mutation analysis of patients with CN type II. Here, we analyzed both the coding and the promoter regions of the gene in seven Japanese patients with CN type II from five unrelated families. The mutations found in this study were classified into three types. The first type was composed of double homozygous missense mutations (Gly71Arg and Tyr486Asp) in exons 1 and 5. These mutations, which were detected in five patients from three unrelated families, were the commonest. The second type, which was detected in one patient, consisted of a single homozygous missense mutation (Arg209Trp) in exon 1. The third type, which was detected in one patient and was a new type of mutation combination, was composed of a homozygous insertion mutation of the TATAA element and a heterozygous missense mutation (Pro229Gln) in exon 1. Although the first and the second type of mutations are recessive, the third type appears to be dominant with incomplete penetrance, since the allele frequency of the insertion mutation of the TATAA element is very high (40%). | ||||||||
| 1154 | 34.44 | 11668616 | 2002.01.22 | + | + | Fine mapping and single nucleotide polymorphism association results of candidate genes for asthma and related phenotypes. | Hum Mutat | |
| T Immervoll, S Loesgen, G Dütsch, H Gohlke, N Herbon, S Klugbauer, A Dempfle, H Bickeböller, J Becker-Follmann, F Rüschendorf, K Saar, A Reis, HE Wichmann, M Wjst, | ||||||||
| Several genome-wide screens for asthma and related phenotypes have been published to date but data on fine-mapping are scarce. For higher resolution we performed a fine-mapping study with 2 cM average spacing in often discussed asthma candidate regions (2p, 5q, 6p, 7p, 9q, 11p, and 12q) to narrow down the regions of interest. All participants of a Caucasian family study (97 families with at least two affected sib pairs) were genotyped for 49 supplementary polymorphic dinucleotide markers. Our results indicate increased evidence for linkage on chromosome 6p, 9q, and 12q. These candidate regions were further analyzed with SNP polymorphisms in the endothelin 1 (EDN1), lymphotoxin alpha (LTA), and neuronal nitric oxide synthase (NOS1) genes. In addition, IL4 -590C>T and IL10 -592C>A, localized on chromosomes 5q and 1q, respectively, have been analyzed for SNP association. Of the six SNPs tested, four revealed weak association with the examined phenotypes. These are the IL10 -592C>A SNP in the interleukin 10 gene (p=0.036 for eosinophil cell counts), the 4124T>C SNP in EDN1 (p=0.044 for asthma), the 3391C>T SNP in NOS1 with eosinophil cell counts (p=0.0086), and the 5266C>T polymorphism, also in the NOS1 gene, for high IgE levels (p=0.022). In summary, fine mapping data enable us to confine asthma candidate regions, while variants of EDN1 and NOS1, or nearby genes, may play an important role in this context. | ||||||||
| 1155 | 34.44 | 17967063 | 2007.11.13 | + | + | Genome-wide profiling of DNA methylation reveals a class of normally methylated CpG island promoters. | PLoS Genet | |
| L Shen, Y Kondo, Y Guo, J Zhang, L Zhang, S Ahmed, J Shu, X Chen, RA Waterland, JP Issa, | ||||||||
| The role of CpG island methylation in normal development and cell differentiation is of keen interest, but remains poorly understood. We performed comprehensive DNA methylation profiling of promoter regions in normal peripheral blood by methylated CpG island amplification in combination with microarrays. This technique allowed us to simultaneously determine the methylation status of 6,177 genes, 92% of which include dense CpG islands. Among these 5,549 autosomal genes with dense CpG island promoters, we have identified 4.0% genes that are nearly completely methylated in normal blood, providing another exception to the general rule that CpG island methylation in normal tissue is limited to X inactivation and imprinted genes. We examined seven genes in detail, including ANKRD30A, FLJ40201, INSL6, SOHLH2, FTMT, C12orf12, and DPPA5. Dense promoter CpG island methylation and gene silencing were found in normal tissues studied except testis and sperm. In both tissues, bisulfite cloning and sequencing identified cells carrying unmethylated alleles. Interestingly, hypomethylation of several genes was associated with gene activation in cancer. Furthermore, reactivation of silenced genes could be induced after treatment with a DNA demethylating agent or in a cell line lacking DNMT1 and/or DNMT3b. Sequence analysis identified five motifs significantly enriched in this class of genes, suggesting that cis-regulatory elements may facilitate preferential methylation at these promoter CpG islands. We have identified a group of non-X-linked bona fide promoter CpG islands that are densely methylated in normal somatic tissues, escape methylation in germline cells, and for which DNA methylation is a primary mechanism of tissue-specific gene silencing. | ||||||||
| 1156 | 34.43 | 11078480 | 2001.01.18 | + | + | The extent of linkage disequilibrium in four populations with distinct demographic histories. | Am J Hum Genet | |
| AM Dunning, F Durocher, CS Healey, MD Teare, SE McBride, F Carlomagno, CF Xu, E Dawson, S Rhodes, S Ueda, E Lai, RN Luben, EJ Van Rensburg, A Mannermaa, V Kataja, G Rennart, I Dunham, I Purvis, D Easton, BA Ponder, | ||||||||
| The design and feasibility of whole-genome-association studies are critically dependent on the extent of linkage disequilibrium (LD) between markers. Although there has been extensive theoretical discussion of this, few empirical data exist. The authors have determined the extent of LD among 38 biallelic markers with minor allele frequencies >.1, since these are most comparable to the common disease-susceptibility polymorphisms that association studies aim to detect. The markers come from three chromosomal regions-1,335 kb on chromosome 13q12-13, 380 kb on chromosome 19q13.2, and 120 kb on chromosome 22q13.3-which have been extensively mapped. These markers were examined in approximately 1,600 individuals from four populations, all of European origin but with different demographic histories; Afrikaners, Ashkenazim, Finns, and East Anglian British. There are few differences, either in allele frequencies or in LD, among the populations studied. A similar inverse relationship was found between LD and distance in each genomic region and in each population. Mean D' is.68 for marker pairs <5 kb apart and is.24 for pairs separated by 10-20 kb, and the level of LD is not different from that seen in unlinked marker pairs separated by >500 kb. However, only 50% of marker pairs at distances <5 kb display sufficient LD (delta>.3) to be useful in association studies. Results of the present study, if representative of the whole genome, suggest that a whole-genome scan searching for common disease-susceptibility alleles would require markers spaced < or = 5 kb apart. | ||||||||
| 1157 | 34.43 | 11897832 | 2002.07.29 | + | Contribution of BRCA2 germline mutations to hereditary breast/ovarian cancer in Germany. | J Med Genet | ||
| U Hamann, X Liu, S Lange, HU Ulmer, A Benner, RJ Scott, | ||||||||
| 1158 | 34.43 | 9467014 | 1998.04.16 | + | + | A new polymorphism in the APOE promoter associated with risk of developing Alzheimer's disease. | Hum Mol Genet | |
| JC Lambert, F Pasquier, D Cottel, B Frigard, P Amouyel, MC Chartier-Harlin, | ||||||||
| The epsilon4 allele of the Apolipoprotein E gene (APOE), one of the main allele of APOE polymorphism, is a major risk factor for the development of Alzheimer's disease. However, several data suggest that genetic factors, within the APOE locus, may also modulate the risk associated with this polymorphism. We look for new mutations in the APOE promoter, susceptible to modify the risk associated with the APOE epsilon4 allele. We characterised a G-->T mutation at -186 bp of the APOE gene TATA box, named Th1/E47cs. This new polymorphism is located in a consensus sequence of a potential transcriptional (Th1/E47) factor binding site. We studied the impact of this new polymorphism with those of other markers of the APOE locus in a large case-control study and observed that Th1/E47cs modulated the influence of the APOE epsilon4 allele on the risk of Alzheimer's disease. | ||||||||
| 1159 | 34.42 | 10548453 | 1999.12.23 | + | + | Biotransformation of alprazolam by members of the human cytochrome P4503A subfamily. | Xenobiotica | |
| JC Gorski, DR Jones, MA Hamman, SA Wrighton, SD Hall, | ||||||||
| 1. To aid in the prediction of drug interactions with alprazolam, the human CYP involved in the 1'- and 4-hydroxylation of alprazolam were characterized using human liver microsomes, expressed enzymes and selective chemical inhibitors. 2. The formation of 4-hydroxyalprazolam and 1'-hydroxyalprazolam at an alprazolam concentration of 62.5 microM were reduced by the prototypic CYP3A inhibitor, troleandomycin (50 microM), by 97 and 9900 respectively. Only microsomes from B-lymphoblastoid cells expressing CYP3A4 were capable of catalysing the 1'- and 4-hydroxylation of alprazolam. 3. The formation rates of 1'-hydroxyalprazolam and 4-hydroxyalprazolam at an alprazolam concentration of 1 mM were significantly correlated (n = 19, r = 0.95, p<0.01) indicating that the same enzyme(s) mediated these biotransformations. A significant (p<0.01) correlation was observed between alprazolam 4- and 1'-hydroxylase activity and CYP3A-mediated midazolam 4-hydroxylase, midazolam 1'-hydroxylase, dextromethorphan N-demethylase and erythromycin N-demethylase activities. 4. In conclusion, in adult human liver the CYP3A subfamily members are the principal enzymes involved in the 1'- and 4-hydroxylation of alprazolam. Thus, clinically significant drug drug interactions between alprazolam and other CYP3A substrates are to be expected. | ||||||||
| 1160 | 34.41 | 16395295 | 2006.05.12 | + | + | Significant association of catechol-O-methyltransferase (COMT) haplotypes with nicotine dependence in male and female smokers of two ethnic populations. | Neuropsychopharmacology | |
| J Beuten, TJ Payne, JZ Ma, MD Li, | ||||||||
| The catechol-O-methyltransferase (COMT) gene plays a prominent role in dopaminergic circuits central to drug reward. Allelic variants within the COMT gene are therefore potential candidates for examining interindividual differences in vulnerability to nicotine dependence (ND). We analyzed five single nucleotide polymorphisms (SNPs), including the Val/Met variant (rs4680), which results in a three- to four-fold difference in enzyme activity within COMT, for association with the three ND measures, SQ, HSI, and FTND, in 602 nuclear families of African-American (AA) or European-American (EA) origin. The Val/Met variant showed a significant association with the three ND measures in the pooled and EA samples and with FTND in the AA sample. Haplotype analysis revealed a major protective A-G-T haplotype (frequency 23.6%) for rs740603-rs4680-rs174699 in the AA sample (minimum Z=-3.35; P=0.0005 for FTND), a major protective T-G-T haplotype (frequency 15.2%; minimum Z=-2.92; P=0.003 for FTND) in the EA sample, and a high-risk C-A-T haplotype (frequency 16.9%; minimum Z=3.16; P=0.002 for SQ) in the AA sample for rs933271-rs4680-rs174699. Furthermore, we found that the significant haplotypes within COMT were gender-specific and the significantly associated A-G-T is protective in AA females only, whereas T-G-T is protective in EA males only. Moreover, we found a major high-risk T-A-T haplotype (frequency 56.7%) that showed significant association with the three ND measures in EA males. Further examination of two protective haplotypes, A-G-T in AAs and T-G-T in EAs, indicated that the low COMT enzyme activity Met allele is protective to become nicotine dependent. In summary, our results provide evidence for a role of COMT in the susceptibility to ND and further confirm that its effect is ethnic and gender specific. | ||||||||
| 1161 | 34.41 | 11858505 | 2002.09.06 | + | Four novel polymorphisms in the fibrinogen Aalpha gene. | Thromb Haemost | ||
| VM Homer, SO Brennan, PM George, | ||||||||
| 1162 | 34.40 | 15118351 | 2004.07.06 | + | + | Cytochrome P-450 2D6*10 C188T polymorphism is associated with antipsychotic-induced persistent tardive dyskinesia in Chinese schizophrenic patients. | Neuropsychobiology | |
| YJ Liou, YC Wang, YM Bai, CC Lin, SC Yu, DL Liao, MW Lin, JY Chen, IC Lai, | ||||||||
| Typical antipsychotic treatment had been postulated to be a risk factor for the susceptibility to tardive dyskinesia (TD). The cytochrome P-450 debrisoquine/sparteine hydroxylase (CYP2D6) metabolizes a majority of antipsychotics and exhibits various phenotypes on enzymatic activities from poor metabolizers to ultrarapid metabolizers. The various phenotypes are encoded by polymorphic genetic variants on the CYP2D6 gene. Although several studies had explored the association between the CYP2D6*10 C188T polymorphism, which encodes the phenotype intermediate metabolizers, and TD in Orientals, the findings were inconclusive. In the present study, we examined the relationship between the CYP2D6*10 C188T polymorphism and the TD occurrence in 216 Chinese schizophrenic patients (113 patients with TD and 103 patients without TD) and explored the correlation between the TD severity assessed by the Abnormal Involuntary Movement Scale (AIMS) and each C188T genotype in the 113 TD patients. Using logistic regression analysis, we found a modest association (p = 0.045) between TD and C188T genotypes. This positive finding was only observed in male patients (p = 0.001), but not in females. Our findings also support the correlation between AIMS scores and C188T polymorphism within the TD group after adjusting for confounding effects with the multiple regression analysis (p = 0.033). We concluded that the CYP2D6*10 C188T polymorphism may be associated with the susceptibility to the occurrence of TD induced by typical antipsychotics, especially in male patients, and may also be correlated with AIMS scores in TD patients. | ||||||||
| 1163 | 34.40 | 10835643 | 2000.06.29 | + | + | Mutations in ABCC6 cause pseudoxanthoma elasticum. | Nat Genet | |
| AA Bergen, AS Plomp, EJ Schuurman, S Terry, M Breuning, H Dauwerse, J Swart, M Kool, S van Soest, F Baas, JB ten Brink, PT de Jong, | ||||||||
| Pseudoxanthoma elasticum (PXE) is a heritable disorder of the connective tissue. PXE patients frequently experience visual field loss and skin lesions, and occasionally cardiovascular complications. Histopathological findings reveal calcification of the elastic fibres and abnormalities of the collagen fibrils. Most PXE patients are sporadic, but autosomal recessive and dominant inheritance are also observed. We previously localized the PXE gene to chromosome 16p13.1 (refs 8,9) and constructed a physical map. Here we describe homozygosity mapping in five PXE families and the detection of deletions or mutations in ABCC6 (formerly MRP6) associated with all genetic forms of PXE in seven patients or families. | ||||||||
| 1164 | 34.39 | 9380062 | 1997.11.07 | + | + | Association of a polymorphism in the dopamine-transporter gene with Parkinson's disease. | Mov Disord | |
| DG Le Couteur, PW Leighton, SJ McCann, S Pond, | ||||||||
| The presynaptic dopamine transporter in nigral dopaminergic neurons confers susceptibility to the cytotoxic effects of the neurotoxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Polymorphisms in the dopamine transporter might influence the susceptibility to such toxins. Therefore, we investigated whether a polymorphic region in the 3'-untranslated region of the dopamine-transporter gene is associated with idiopathic Parkinson's disease (PD). The frequency distribution of the alleles was significantly different between the patients (n = 100) and controls (n = 200, p < 0.05). The rare 11-copy allele was more common in the patients (odds ratio = 10.2, 95% confidence interval - 1.2-87.9, p < 0.025). The susceptibility of some people to PD may be conferred by polymorphisms in the dopamine-transporter gene that could lead to increased cellular accumulation of neurotoxic compounds in dopaminergic neurons. | ||||||||
| 1165 | 34.39 | 10486320 | 2000.10.02 | + | + | The contribution of germline BRCA1 and BRCA2 mutations to familial ovarian cancer: no evidence for other ovarian cancer-susceptibility genes. | Am J Hum Genet | |
| SA Gayther, P Russell, P Harrington, AC Antoniou, DF Easton, BA Ponder, | ||||||||
| To establish the contribution of germline BRCA1 and BRCA2 mutations to familial ovarian cancer, we have analyzed both genes in DNA samples obtained from an affected individual in each of 112 families containing at least two cases of epithelial ovarian cancer. Germline mutations were found in 43% of the families; BRCA1 mutations were approximately four times more common than BRCA2 mutations. The extent of family history of ovarian and breast cancers was strongly predictive of BRCA1-mutation status. Segregation analysis suggests that a combination of chance clustering of sporadic cases and insensitivity of mutation detection may account for the remaining families; however, the contribution of other genes cannot be excluded. We discuss the implications for genetic testing and clinical management of familial ovarian cancer arising from the data presented in these studies. | ||||||||
| 1166 | 34.39 | 11310576 | 2001.05.21 | + | + | Interaction of folate and homocysteine pathway genotypes evaluated in susceptibility to neural tube defects (NTD) in a German population. | J Hum Genet | |
| B Richter, K Stegmann, B Röper, I Böddeker, ET Ngo, MC Koch, | ||||||||
| Neural tube defects (NTD) are likely to result from an interaction of several genes and environmental factors. Because periconceptional folate intake reduces the NTD risk in the fetus, and because mothers of children with NTD showed elevated plasma homocysteine levels, gene polymorphisms of the folate and homocysteine pathway, such as 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C-->T, MTHFR 1298A-->C and cystathionine beta-synthase (CBS) 844ins68, have been implicated in the etiology of NTD. Several studies have demonstrated that these polymorphisms may indeed be associated with NTD in some populations. In order to evaluate the role of these polymorphisms and their interaction in NTD, we genotyped 417 individuals for case-control studies and 129 families for transmission disequilibrium tests. We are the first to present detailed data on MTHFR haploid genotypes in combination with CBS 844ins68. The MTHFR risk genotype 677CT/1298AC, known to be associated with decreased enzyme activity and increased homocysteine, was found significantly more often in patients than in controls (P = 0.02). A CBS insertion allele in addition to MTHFR 677CT/ 1298AC heterozygosity or MTHFR 677TT/1298AA homozygosity did not result in an increased risk for NTD. This is in agreement with the recently reported homocysteine-lowering effect of the CBS 844ins68 allele in carriers of MTHFR variants. | ||||||||
| 1167 | 34.38 | 12151999 | 2002.08.20 | + | + | Hepatic but not intestinal CYP3A4 displays dose-dependent induction by efavirenz in humans. | Clin Pharmacol Ther | |
| S Mouly, KS Lown, D Kornhauser, JL Joseph, WD Fiske, IH Benedek, PB Watkins, | ||||||||
| OBJECTIVE: The capacity of the non-nucleoside reverse transcriptase inhibitor efavirenz to induce either liver CYP3A4 or intestinal CYP3A4, or both, as well as intestinal P-glycoprotein, was evaluated in healthy volunteers during and after a 10-day treatment course with two different daily doses. METHODS: Cohorts of 12 healthy subjects were randomized (2:1) to receive either efavirenz or placebo orally for 10 days. The first cohort received 200 mg efavirenz and the second cohort received 400 mg efavirenz daily. Liver CYP3A4 activity was evaluated on 9 different occasions with use of the erythromycin breath test (ERMBT). Intestinal biopsy specimens were obtained before the first dose of efavirenz and on the day after administration of the last dose to measure intestinal CYP3A4 and P-glycoprotein contents by immunoblotting. Efavirenz plasma levels were measured by HPLC, and pharmacokinetic parameters were determined by standard noncompartmental methods. RESULTS: Efavirenz significantly increased the mean ERMBT result in a dose- and time-dependent manner, with a 55% mean induction at 400 mg and a 33% mean induction at 200 mg (P <.01, compared with placebo for each treatment). The efavirenz AUC on day 10 correlated with the magnitude of induction (day 11/day 1 ERMBT ratio) when the two dose groups were combined (r = 0.509; P =.04). In contrast, efavirenz treatment had no detectable effect on intestinal CYP3A4 or P-glycoprotein. CONCLUSIONS: Efavirenz is an inducer of liver CYP3A4 in healthy volunteers, and interpatient differences in magnitude of induction is partly explained by variation in systemic drug exposure. However, efavirenz did not appear to induce intestinal CYP3A4 or intestinal P-glycoprotein. These results suggest that drug interactions caused by induction of CYP3A4 can be liver specific. | ||||||||
| 1168 | 34.38 | 9524244 | 1998.05.13 | + | + | Identification of a novel transcriptional silencer in the protein-coding region of the human CYP2C9 gene. | Gene | |
| S Xiang, HK Parsons, M Murray, | ||||||||
| A novel regulatory element (27 bp) which confers transcriptional repression was identified within the protein-coding region immediately after the translation start codon in the human cytochrome P450 (CYP) 2C9 gene. Deletion of this element increased transcriptional activity in HepG2 cells by transient transfection assay. Nuclear protein extracts from HepG2 cells and human liver were found in electrophoretic mobility shift assays to bind specifically to the 27 bp element. A putative binding protein was partially purified by DNA-affinity chromatography and was determined by Southwestern blotting to have a molecular weight of approx. 100 kDa. Studies with mutated competitor oligonucleotides established that binding of the nuclear protein to the 27 bp cis-element was dependent upon two 6 bp direct repeats (5'-CTTGTG-3') that were separated by three bases. It is possible that this novel cis-acting element may be involved in the negative regulation of CYP2C9. | ||||||||
| 1169 | 34.38 | 10479723 | 1999.09.21 | + | + | Human transcription factor SLUG: mutation analysis in patients with neural tube defects and identification of a missense mutation (D119E) in the Slug subfamily-defining region. | Mutat Res | |
| K Stegmann, J Boecker, C Kosan, A Ermert, J Kunz, MC Koch, | ||||||||
| Studies in mouse, chicken and Xenopus have shown that Slug is selectively expressed in the dorsal part of the developing neural tube. Ablation and antisense experiments in chicken suggest that Slug may be an important factor during neural tube closure. We therefore investigated the role of Slug as a possible candidate contributing to the aetiology of neural tube defects (NTD) in humans. We characterised the genomic structure of human SLUG including determination of the exon-intron boundaries. The coding sequence of SLUG was screened for mutations in 150 patients with NTD using single strand conformation analysis (SSCA). In one patient, we identified a missense mutation 1548C-->A in exon 2 causing an exchange of a conserved amino acid (D119E) in the Slug subfamily-defining region preceding the first zinc finger. This is the first description of a human mutation in the SLUG gene. In accordance with the findings in model organisms, the SLUG mutation may be causally related to the development of NTD in our patient and could be considered as a predisposing factor. | ||||||||
| 1170 | 34.38 | 17620546 | 2007.08.13 | + | + | Heterogeneity within a large kindred with frontotemporal dementia: a novel progranulin mutation. | Neurology | |
| AC Bruni, P Momeni, L Bernardi, C Tomaino, F Frangipane, J Elder, T Kawarai, C Sato, S Pradella, Y Wakutani, M Anfossi, M Gallo, S Geracitano, A Costanzo, N Smirne, SA Curcio, M Mirabelli, G Puccio, R Colao, RG Maletta, A Kertesz, P St George-Hyslop, J Hardy, E Rogaeva, | ||||||||
| BACKGROUND: Frontotemporal dementia (FTD) in several 17q21-linked families was recently explained by truncating mutations in the progranulin gene (GRN). OBJECTIVE: To determine the frequency of GRN mutations in a cohort of Caucasian patients with FTD without mutations in known FTD genes. METHODS: GRN was sequenced in a series of 78 independent FTD patients including 23 familial subjects. A different Calabrian dataset (109 normal control subjects and 96 FTD patients) was used to establish the frequency of the GRN mutation. RESULTS: A novel truncating GRN mutation (c.1145insA) was detected in a proband of an extended consanguineous Calabrian kindred. Segregation analysis of 70 family members revealed 19 heterozygous mutation carriers including 9 patients affected by FTD. The absence of homozygous carriers in a highly consanguineous kindred may indicate that the loss of both GRN alleles might lead to embryonic lethality. An extremely variable age at onset in the mutation carriers (more than five decades apart) is not explained by APOE genotypes or the H1/H2 MAPT haplotypes. Intriguingly, the mutation was excluded in four FTD patients belonging to branches with an autosomal dominant mode of inheritance of FTD, suggesting that another novel FTD gene accounts for the disease in the phenocopies. It is difficult to clinically distinguish phenocopies from GRN mutation carriers, except that language in mutation carriers was more severely compromised. CONCLUSION: The current results imply further genetic heterogeneity of frontotemporal dementia, as we detected only one GRN-linked family (about 1%). The value of discovering large kindred includes the possibility of a longitudinal study of GRN mutation carriers. | ||||||||
| 1171 | 34.37 | 17194541 | 2007.04.27 | + | + | A polymorphism of LOC387715 gene is associated with age-related macular degeneration in the Japanese population. | Neurosci Lett | |
| S Tanimoto, H Tamura, T Ue, K Yamane, H Maruyama, H Kawakami, Y Kiuchi, | ||||||||
| Age-related macular degeneration (AMD) is one of the leading causes of blindness among older adults in developed countries and also in Japan. Previous research suggests that AMD is etiologically a complex disease, caused by multiple genes and environmental factors. Association studies have identified that a complement factor H gene (CFH) variant is a major risk factor for AMD in Caucasians. However, we and two other groups have reported no association between CFH and AMD in the Japanese population. Recent studies have suggested that LOC387715 on chromosome 10q26 may be the second major risk loci for AMD in Caucasians. In this study, we examined the association between LOC387715 and AMD in Japanese, and our results show that polymorphism of the LOC387715 gene is associated with AMD in Japanese as well as in Caucasians. Our data show a disease odds ratio of 6.20 (95% CI: 2.87-13.40) conferred by homozygosity for risk alleles at LOC387715 compared with the non-risk genotype. A polymorphism of LOC387715 gene is associated with AMD in the Japanese population. | ||||||||
| 1172 | 34.36 | 11850848 | 2002.03.08 | + | + | p21B, a variant of p21(Waf1/Cip1), is induced by the p53 family. | Oncogene | |
| S Nozell, X Chen, | ||||||||
| Alternative splicing or expression from an alternate promoter can produce variants of a gene. To determine whether the p21(Waf1/Cip1) locus is regulated by these mechanisms, we searched for and found two transcripts, p21B and p21C, that are expressed from an alternate promoter in the first intron of the p21 gene. While p21C encodes the p21 cyclin-dependent kinase inhibitor, p21B encodes a novel protein and the transcript is ubiquitously expressed in 16 human tissues tested. Like p21, both p21B and p21C are induced by DNA damage, p53, and other p53 family members through a proximal p53 response element in the promoter of p21B and p21C. However, unlike p21, which induces cell cycle arrest, we found that overexpression of p21B induces apoptosis. These findings indicate that the p21 locus expresses at least two structurally distinct, but functionally related, variants of the p21 gene from discrete promoters. | ||||||||
| 1173 | 34.36 | 8661122 | 1996.09.30 | + | + | Coamplification in tumors of KRAS2, type 2 inositol 1,4,5 triphosphate receptor gene, and a novel human gene, KRAG. | Genomics | |
| J Heighway, DC Betticher, PR Hoban, HJ Altermatt, R Cowen, | ||||||||
| Analysis of a region of DNA, coamplified in tumors with KRAS2, resulted in the identification of the human homologue of the mouse KRAG gene. The gene was widely expressed in a range of cell lines, tumors, and normal tissue and demonstrated a high degree of alternate splicing. A human KRAG cDNA sequence, with a structure similar to that encoded by the amplified gene in mouse Y1 adrenal carcinoma cells, was isolated by RT-PCR. The predicted amino acid similarity between the two sequences was 91%, and hydrophobicity plots suggested a structure closely resembling that of transmembrane 4 superfamily members. Identification of a PCR-based restriction fragment length polymorphism confirmed biallelic expression of KRAG but suggested allele-specific splicing differences in tumors. Northern analysis of mRNA derived from a range of tissues suggested high level expression in muscle and confirmed alternate splicing. To facilitate the analysis of exon junctions, a YAC clone encoding the genomic sequence was identified. This allowed the localization of KRAG to human chromosome 12p11.2. Isolation of one end of this nonchimeric clone demonstrated a perfect match with a 247-bp sequence within the 3' untranslated region of the type 2 1,4, 5-inositol triphosphate receptor gene. Multiplex PCR confirmed the inclusion of both genes in the KRAS2 amplicon in human malignancy, suggesting that either may contribute to the malignant phenotype. | ||||||||
| 1174 | 34.36 | 8639263 | 1996.07.12 | + | + | Human drug-metabolizing enzyme polymorphisms: effects on risk of toxicity and cancer. | DNA Cell Biol | |
| DW Nebert, RA McKinnon, A Puga, | ||||||||
| A growing number of human genetic polymorphisms in drug-metabolizing enzymes (DMEs) are being characterized. Some of these have been shown, quite convincingly, to be correlated with risk of toxicity or cancer, whereas others presently remain equivocal. There is good evidence that the correlation is stronger in populations exposed to a variety of environmental procarcinogens; perhaps 30% of DME substrates are able to be metabolically potentiated. Phase I DMEs, most of which represent cytochromes P450, metabolically activate procarcinogens to genotoxic electrophilic intermediates, and Phase II DMEs conjugate the intermediates to water-soluble derivatives, completing the detoxification cycle. It follows that genetic differences in the regulation, expression and activity of genes coding for Phase I and Phase II DMEs would be crucial factors in defining cancer susceptibility and the toxic or carcinogenic power of environmental chemicals. Not all Phase I and Phase II DMEs are implicated in detoxification; previous work from this and from other laboratories has identified candidate Phase I and Phase II genes in which certain alleles are more likely to be associated with cancer susceptibility. In some cases, the allelic frequencies vary dramatically between ethnic groups. In this review, our current knowledge about polymorphisms in the following genes are updated: the aromatic hydrocarbon receptor (AHR), the CYP1A1 structural gene (which encodes aryl hydrocarbon hydroxylase activity), the CYP1A2 structural gene (arylamine oxidations), the CYP2C19 gene (S-mephenytoin 4'-hydroxylase), the CYP2D6 gene (debrisoquine hydroxylase), the CYP2E1 gene (N,N-dimethylnitrosamine N-demethylase), the null mutant for the GSTM1 gene (glutathione transferase mu), and the NAT2 gene (arylamine N-acetyltransferase). If unequivocal biomarkers of genetic susceptibility to cancer and toxicity can be developed successfully, then identification of individuals at increased risk would be very helpful in the fields of public health and preventive medicine. | ||||||||
| 1175 | 34.35 | 10634134 | 2000.01.28 | + | + | Analysis of the CYP2D6 gene mutations and their consequences for enzyme function in a West African population. | Pharmacogenetics | |
| EU Griese, S Asante-Poku, D Ofori-Adjei, G Mikus, M Eichelbaum, | ||||||||
| The data on differences in the metabolic handling of the CYP2D6 probe drugs sparteine and debrisoquine, and the relationship between phenotype and genotype and gene frequencies for several mutant CYP2D6 alleles in African populations are limited and sometimes controversial. Therefore, in a West African population (Ghana), we investigated (i) the phenotype for sparteine debrisoquine by phenotyping 201 individuals with both drugs and (iii) the genotype for CYP2D6 (n = 326) and debrisoquine (n = 201) oxidation, (ii) the coregulatory control of sparteine and alleles *3 and *4 in 133 individuals and for the alleles *1, *2, *3, *4, *5, *6, *7, *8, *9, *10, *14, *16, *17, *2b, *2xN, *2bxN in 193 individuals. Of the 326 individuals phenotyped with sparteine, eight had a metabolic ratio (MR)sp > 20 corresponding to a poor metabolizer frequency of 2.5% [95% (confidence interval) CI = 1.06-4.77]. The prevalence of the poor metabolizer phenotype for debrisoquine oxidation was 3% (95% CI = 1.1-6.39) with six of the 201 individuals having a MR greater than 12.6. The distribution of the MR of sparteine was trimodal whereas MR of debrisoquine was unimodally distributed with a pronounced kurtosis. In individuals phenotyped with both drugs, there was a significant correlation between the MRs (r(s) = 0.63, P < 0.001). The CYP2D6 alleles *1, *2 and *17 were the most common functional alleles occurring with frequencies of 43.7, 10.6 and 27.7%, respectively. The three other observed functional alleles *2xN, *10 and *20 had much lower frequencies (1.6%, 3.1% and 0.3%, respectively). Of the eight non-functional alleles, only *4 (6.3%) and *5 (6.0%) could be found. The allele *5 occurred with the same frequency as in Caucasian populations (4.1%) but the *4 allele had a much lower frequency (Caucasians 19.5%). One individual with *1/*1 was a poor metabolizer for sparteine and debrisoquine indicating the existence of as yet unknown non-functional alleles in this West African population. Although the prevalence of poor metabolizers and the number of heterozygotes for non-functional alleles was much lower in Ghanaians, the median MRsp of 0.7 was significantly higher in this population compared with a median MRsp of 0.4 in Caucasians, indicating a lower metabolic clearance for CYP2D6 substrates in the West Africans. The lower metabolic activity in Ghanaians could not be explained solely by the high frequency of the *17 allele, which is associated with an impairment of CYP2D6 enzyme function. In addition, a higher median MRsp of 0.5 corresponding to metabolic clearance of 346 ml/min was observed among extensive metabolizers with the genotype *1/*1. Thus, compared with the median of MRsp = 0.28 (CLmet 573 ml/min) in Caucasians homozygous for *1, the metabolic clearance of sparteine was 40% lower on average in respective Ghanaians. | ||||||||
| 1176 | 34.35 | 9826540 | 1998.12.30 | + | + | Modulation of MDR1 and CYP3A expression by dexamethasone: evidence for an inverse regulation in adrenals. | Biochem Biophys Res Commun | |
| E Sérée, PH Villard, A Hevér, N Guigal, F Puyoou, B Charvet, H Point-Scomma, E Lechevalier, B Lacarelle, Y Barra, | ||||||||
| A strong overlap exists between gp170 and CYP3A substrates and inducers. In order to investigate a putative coregulation of MDR and CYPA gene expression, we measured their transcripts in human liver and after dexamethasone treatment in HepG2 cells or in different mouse tissues. In human liver, we observed no correlation between MDR1 and CYP3A4 expression, whereas these genes were coinduced by dexamethasone in HepG2 cells. In mouse liver treated with dexamethasone, mdr1b and Cyp3a were induced (5- and 2-fold, respectively). In adrenals, the main expressing gp170 tissue, Cyp3a, was increased while mdr1b was repressed (-51%). The expression of mdr1b increased in heart, brain, and colon and decreased in lung and kidney but Cyp3a was not detectable. In conclusion, human hepatic CYP3A4 and MDR1 are not corregulated but are coinducible. In vivo murine mdr1b and Cyp3a are coregulated by dexamethasone in liver and inversely regulated in adrenals. | ||||||||
| 1177 | 34.35 | 12807698 | 2003.10.17 | + | + | Norepinephrine transport by the extraneuronal monoamine transporter in human bronchial arterial smooth muscle cells. | Am J Physiol Lung Cell Mol Physiol | |
| G Horvath, Z Sutto, A Torbati, GE Conner, M Salathe, A Wanner, | ||||||||
| Inhaled glucocorticosteroids (GSs) cause acute, alpha1-adrenoreceptor (AR)-mediated bronchial vasoconstriction. After release from sympathetic nerves, norepinephrine (NE) must be taken up into cells for deactivation by intracellular enzymes. Because postsynaptic cellular NE uptake is steroid sensitive, GSs could increase NE concentrations at alpha1-AR, causing vasoconstriction. We therefore evaluated mRNA expression of different NE transporters in human bronchial arterial smooth muscle and pharmacologically characterized NE uptake into these cells. RT-PCR demonstrated mRNA expression of the extraneuronal monoamine transporter (EMT) and organic cation transporter 1 (OCT-1). Fluorometric uptake assay showed time (within minutes)- and concentration-dependent NE uptake by freshly isolated bronchial arterial smooth muscle cells (SMC) with an estimated Km of 240 microM. Corticosterone and O-methylisoprenaline (1 microM each), but not desipramine, inhibited NE uptake, a profile indicative of NE uptake by EMT, but not OCT-1. Budesonide and methylprednisolone inhibited uptake with IC50 values of 0.9 and 5.6 microM, respectively. Corticosterone's action was reversible and not sensitive to RU-486 (GS receptor antagonist), actinomycin D (transcription inhibitor), or cycloheximide (protein synthesis inhibitor). Corticosterone made membrane impermeant by coupling to BSA also blocked NE uptake. Immunocytochemistry indicated a specific membrane binding site for corticosterone on bronchial arterial SMC. These data demonstrate that although human bronchial arterial SMC express OCT-1 and EMT, EMT is the predominant plasma membrane transporter for NE uptake. This process can be inhibited by GSs, likely via a specific membrane binding site. This nongenomic GS action (increasing NE concentrations at alpha1-AR) could explain acute bronchial vasoconstriction caused by inhaled GSs. | ||||||||
| 1178 | 34.34 | 11324941 | 2001.08.09 | + | + | Polymorphisms of tryptophan hydroxylase gene and the symptomatology of schizophrenia: an association study. | Psychiatr Genet | |
| T Shinkai, O Ohmori, T Suzuki, H Kojima, H Hori, T Terao, J Nakamura, | ||||||||
| Serotonergic neurotransmission may be involved in the etiology of schizophrenia. We systematically searched for human tryptophan hydroxylase (TPH) coding polymorphisms, and detected a novel pentanucleotide repeat deletion polymorphism (GTTTT)4/5 in TPH intron 1b. We also confirmed A779C intron 7. Neither polymorphism showed a significant association with schizophrenia (182 patients with schizophrenia, 148 controls). A significant association, however, between A779C genotypes and the total Manchester Scale (MS) scores was found in male patients (P = 0.045). Subsequently, a significant association was also found between A779C genotypes and the MS negative symptoms scores in male patients (P = 0.030). These results suggest that the TPH gene may play a role in the negative symptoms in male patients with schizophrenia. | ||||||||
| 1179 | 34.34 | 11360030 | 2001.08.23 | + | + | Pharmacokinetic drug interaction potential of risperidone with cytochrome p450 isozymes as assessed by the dextromethorphan, the caffeine, and the mephenytoin test. | Ther Drug Monit | |
| CB Eap, G Bondolfi, D Zullino, C Bryois, M Fuciec, L Savary, M Jonzier-Perey, P Baumann, | ||||||||
| Two published case reports showed that addition of risperidone (1 and 2 mg/d) to a clozapine treatment resulted in a strong increase of clozapine plasma levels. As clozapine is metabolized by cytochrome P450 isozymes, a study was initiated to assess the in vivo interaction potential of risperidone on various cytochrome P450 isozymes. Eight patients were phenotyped with dextromethorphan (CYP2D6), mephenytoin (CYP2C19), and caffeine (CYP1A2) before and after the introduction of risperidone. Before risperidone, all eight patients were phenotyped as being extensive metabolizers of CYP2D6 and CYP2C19. Risperidone at dosages between 2 and 6 mg/d does not appear to significantly inhibit CYP1A2 and CYP2C19 in vivo (median plasma paraxanthine/caffeine ratios before and after risperidone: 0.65, 0.69; p = 0.89; median urinary (S)/(R) mephenytoin ratios before and after risperidone:0.11, 0.12; p = 0.75). Although dextromethorphan metabolic ratio is significantly increased by risperidone (median urinary dextromethorphan/dextrorphan ratios before and after risperidone: 0.010, 0.018; p = 0.042), risperidone can be considered a weak in vivo CYP2D6 inhibitor, as this increase is modest and none of the eight patients was changed from an extensive to a poor metabolizer. The reported increase of clozapine concentrations by risperidone can therefore not be explained by an inhibition of CYP1A2, CYP2D6, CYP2C19 or by any combination of the three. | ||||||||
| 1180 | 34.33 | 12874030 | 2003.08.13 | + | + | The oncogene phosphatidylinositol 3'-kinase catalytic subunit alpha promotes angiogenesis via vascular endothelial growth factor in ovarian carcinoma. | Cancer Res | |
| L Zhang, N Yang, D Katsaros, W Huang, JW Park, S Fracchioli, C Vezzani, IA Rigault de la Longrais, W Yao, SC Rubin, G Coukos, | ||||||||
| The gene of phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) has been implicated as an oncogene in ovarian cancer [L. Shayesteh et al., Nat. Genet., 21: 99-102, 1999]. In this study, we examined the expression of PIK3CA mRNA and its p110alpha protein product in human ovarian carcinoma and investigated its role in regulating angiogenesis via vascular endothelial growth factor (VEGF). PIK3CA mRNA was detected in 66.6% of stage I and 93.9% of advanced stage ovarian cancer specimens and in all 17 ovarian cancer cell lines. PIK3CA mRNA levels were significantly higher in invasive carcinomas compared with benign and low malignant potential neoplasms (P = 0.007), but no significant difference was seen between early and advanced stage carcinomas (P = 0.812). Strong expression of immunoreactive p110alpha was detected in tumor cells and/or stroma endothelium. PIK3CA expression in vivo positively correlated, both at the mRNA and the protein level, with the expression of VEGF as well as with the extent of microvascular development. Furthermore, PIK3CA mRNA overexpression positively correlated with increased proliferation and decreased apoptosis of tumor cells in vivo. In vitro, PIK3CA expression positively correlated with the expression of VEGF in ovarian cancer cells, whereas the phosphatidylinositol 3'-kinase inhibitor Ly294002 reduced both the constitutive and inducible expression of hypoxia-inducible factor-1alpha at the mRNA and protein levels and abrogated VEGF up-regulation by glucose starvation. Furthermore, Ly294002 suppressed cell proliferation and, at higher doses, induced marked apoptosis in ovarian cancer cells. Collectively, these data strongly indicate that PIK3CA supports ovarian cancer growth through multiple and independent pathways affecting cell proliferation, apoptosis and angiogenesis, and plays an important role in ovarian cancer progression. | ||||||||
| 1181 | 34.33 | 12419832 | 2002.12.20 | + | + | A pharmacogenetic study to investigate the role of dietary carcinogens in the etiology of colorectal cancer. | Carcinogenesis | |
| C Sachse, G Smith, MJ Wilkie, JH Barrett, R Waxman, F Sullivan, D Forman, DT Bishop, CR Wolf, | ||||||||
| Susceptibility to colorectal cancer, one of the most common forms of cancer in the Western world, has been associated with several environmental and dietary risk factors. Dietary exposure to food derived heterocyclic amine carcinogens and polycyclic aromatic hydrocarbons have been proposed as specific risk factors. Many polymorphic Phase I and Phase II drug metabolizing enzymes are responsible for the metabolism and disposition of these compounds and it is therefore possible that inheritance of specific allelic variants of these enzymes may influence colorectal cancer susceptibility. In a multicenter case-control study, 490 colorectal cancer patients and 593 controls (433 matched case-control pairs) were genotyped for common polymorphisms in the cytochrome P450 (CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2C9, CYP2C19 and CYP2D6), glutathione S-transferase (GSTM1, GSTP1 and GSTT1), sulfotransferase (SULT1A1 and SULT1A2), N-acetyl transferase 2 (NAT2), NAD(P)H:quinone oxidoreductase (NQO1), methylenetetrahydrofolate reductase (MTHFR), and microsomal epoxide hydrolase (EPHX1) genes. Matched case-control analysis identified alleles associated with higher colorectal cancer risk as carriage of CYP1A1*2C (OR = 2.15, 95% CI 1.36-3.39) and homozygosity for GSTM1*2/*2 (OR = 1.53, 95% CI 1.16-2.02). In contrast, inheritance of the CYP2A6*2 (OR = 0.51, 95% CI 0.28-1.06), CYP2C19*2 (OR = 0.72, 95% CI 0.52-0.98) and the EPHX1(His113) alleles were associated with reduced cancer risk. We found no association with colorectal cancer risk with NAT2 genotype or any of the other polymorphic genes associated with the metabolism and disposition of heterocyclic amine carcinogens. This data suggests that heterocyclic amines do not play an important role in the aetiology of colorectal cancer but that exposure to other carcinogens such as polycyclic aromatic hydrocarbons may be important determinants of cancer risk. | ||||||||
| 1182 | 34.32 | 10397241 | 1999.07.28 | + | + | Association of the NAD(P)H:quinone oxidoreductase 609C-->T polymorphism with a decreased lung cancer risk. | Cancer Res | |
| H Chen, A Lum, A Seifried, LR Wilkens, L Le Marchand, | ||||||||
| The NAD(P)H:quinone oxidoreductase gene, NQO1, often carries a C-->T transition at bp 609, which has been associated with a reduced enzymatic activity and which may result in altered metabolic activation of tobacco smoke procarcinogens. We tested the association of this polymorphism with lung cancer risk in a population-based case-control study of 327 cases and 440 controls of Caucasian, Japanese, or Native Hawaiian ancestry in Hawaii. We found a notable difference in the frequency of the variant allele among Japanese (38%), Caucasians (20%), and Hawaiians (22%). Overall, the variant allele was less frequent in cases than in controls (P = 0.03). A significant inverse association was found in Japanese, with adjusted odds ratios of 0.8 (95% confidence interval, 0.4-1.5) and 0.3 (0.1-0.7) for the heterozygous and homozygous variant genotypes, respectively, compared with the homozygous wild-type genotype (P for genetic trend, 0.02). The association did not reach statistical significance in Caucasians and Hawaiians but was in the same direction. | ||||||||
| 1183 | 34.31 | 11239904 | 2001.06.28 | + | + | Haplotype study of three polymorphisms at the dopamine transporter locus confirm linkage to attention-deficit/hyperactivity disorder. | Biol Psychiatry | |
| CL Barr, C Xu, J Kroft, Y Feng, K Wigg, G Zai, R Tannock, R Schachar, M Malone, W Roberts, MM Nöthen, F Grünhage, DJ Vandenbergh, G Uhl, G Sunohara, N King, JL Kennedy, | ||||||||
| BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is often treated using methylphenidate, a psychostimulant that inhibits the dopamine transporter. This led E.H. Cook and colleagues to consider the dopamine transporter locus (DAT1) as a primary candidate gene for ADHD. That group reported a significant association between ADHD and the 480-base pair (bp) allele of the variable number of tandem repeats (VNTR) polymorphism located in the 3' untranslated region of the DAT1 gene. This association was later replicated in additional studies. METHODS: The DAT1 gene has additional common polymorphisms in intron 9 and exon 9. We investigated the possibility of linkage of DAT1 and ADHD using the VNTR polymorphism and two additional common polymorphisms in 102 nuclear families with an ADHD proband. Using the transmission disequilibrium test, we examined the transmission of the alleles of each of these polymorphisms, as well as the haplotypes of the polymorphisms. RESULTS: We did not observe significant evidence for the biased transmission of the alleles of either the VNTR or the additional two polymorphisms when examined individually, although there was a trend for the biased transmission of the 480-bp allele of the VNTR. When we examined the haplotypes of the three polymorphisms we found significant evidence for biased transmission of one of the haplotypes containing the 480-bp VNTR allele. We also genotyped six additional DNA sequence variants of the DAT1 gene. However, these variants were not sufficiently polymorphic in our sample to be informative. Two of the DNA variants that result in an amino acid change, Ala559Val and Glu602Gly, were not observed in our sample. CONCLUSIONS: Our results support previous findings of an association between the DAT1 gene and ADHD. | ||||||||
| 1184 | 34.31 | 10974341 | 2000.12.07 | + | Two expressive polymorphisms on the endothelial nitric oxide synthase gene (intron4, 27 bp repeat and -786 T/C) and the venous thromboembolism. | Thromb Res | ||
| AJ Ordóñez, JM Carreira, AG Franco, LM Sánchez, MV Alvarez, EC García, | ||||||||
| 1185 | 34.30 | 7981678 | 1995.01.05 | + | + | Identical genotypes in siblings with different homocystinuric phenotypes: identification of three mutations in cystathionine beta-synthase using an improved bacterial expression system. | Hum Mol Genet | |
| R de Franchis, V Kozich, RR McInnes, JP Kraus, | ||||||||
| We determined the molecular basis of cystathionine beta-synthase (CBS) deficiency in three siblings with pyridoxine responsive homocystinuria using a significantly improved mutation screening method in bacteria. The phenotypic expression of the siblings differed even though their CBS genotypes were identical. The paternal allele contained a linked pair of mutations, C233G and G306C, corresponding to P78R and K102N in the polypeptide chain. Together, these inactivated the enzyme; however, expressed separately, they reduced activity by about one half. The single maternal mutation G715A (E239K) effectively abolished CBS activity. Subunits of CBS were absent from patient fibroblast extracts; however, E. coli, transformed with plasmids containing patient CBS cDNA, expressed the subunits, although in reduced amounts. The mother, an obligate heterozygote, was free from all signs of homocystinuria; nonetheless, extracts of her fibroblasts were devoid of CBS protein and activity. We conclude that fibroblast levels of CBS are only partially effective as prognosticators of disease severity and that it is important to test the in vivo response to vitamin B6 in all cases of homocystinuria, including those in which the mutations lead to the absence of the enzyme in cultured fibroblasts. | ||||||||
| 1186 | 34.30 | 17301252 | 2007.04.03 | + | + | Common genetic variation in TP53 is associated with lung cancer risk and prognosis in African Americans and somatic mutations in lung tumors. | Cancer Epidemiol Biomarkers Prev | |
| LE Mechanic, ED Bowman, JA Welsh, MA Khan, N Hagiwara, L Enewold, PG Shields, L Burdette, S Chanock, CC Harris, | ||||||||
| Lung cancer is primarily caused by tobacco smoking, but susceptibility is likely modified by common genetic variation. In response to many forms of cellular stress, including DNA damage, the p53 protein functions to induce cell cycle arrest, DNA repair, senescence, or apoptosis. We hypothesized that common TP53 haplotypes modulate pathways of lung carcinogenesis and lung cancer susceptibility or prognosis. To investigate our hypothesis, 14 polymorphisms in TP53, including haplotype tagging and coding single nucleotide polymorphisms, were genotyped in two studies from the greater Baltimore, Maryland area. One study is a case-control study and the second is a case-only study for which TP53 mutational spectra data are available. African Americans with Pro-T-A-G-G haplotypes of the combined TP53 polymorphisms TP53_01 (rs1042522), TP53_65 (rs9895829), TP53_66 (rs2909430), TP53_16 (rs1625895), and TP53_11 (rs12951053) had both an increased risk for lung cancer (odds ratio, 2.32; 95% confidence interval, 1.18-4.57) and a worsened lung cancer prognosis (hazards ratio, 2.38; 95% confidence interval, 1.38-4.10) compared with those with Arg-T-A-G-T haplotypes. No associations of TP53 polymorphisms with lung cancer were observed in Caucasians. In the case-only study, several polymorphisms in TP53 and TP53 haplotypes, overlapping regions of TP53 associated with risk and prognosis in African Americans, were associated with increased odds of somatic TP53 mutation in lung tumors in Caucasians. In conclusion, common genetic variation in TP53 could modulate lung cancer pathways, as suggested by the association with lung cancer in African Americans and somatic TP53 mutation frequency in lung tumors. | ||||||||
| 1187 | 34.28 | 15072827 | 2004.06.15 | + | + | CYP1B1 and CYP19 gene polymorphisms and breast cancer incidence: no association in the ARIC study. | Cancer Lett | |
| B Thyagarajan, M Brott, P Mink, AR Folsom, KE Anderson, WS Oetting, M Gross, | ||||||||
| We conducted a nested case control study of 178 incident breast cancer cases and 356 controls in the Atherosclerosis Risk in Communities study. We evaluated the association between breast cancer and Val432Leu polymorphism in the CYP1B1 gene and the tetranucleotide repeats in intron 4 of the CYP19 gene. After adjustment for height, age at menopause, age at menarche, BMI, HRT, and alcohol intake, carriers of the Val/Leu or Val/Val genotype had a 1.45 fold (95% CI 0.85-2.47) greater odds of breast cancer than Leu/Leu carriers. There was no association of the breast cancer with any individual CYP19 allele. Compared to individuals homozygous with the 167 allele, odds ratios were close to 1.0 for the 167 heterozygous genotype and for the remaining tetranucleotide repeats combined. Our data shows no association between breast cancer and the Leu432Val polymorphism of the CYP1B1 gene or the tetranucleotide repeats of the CYP19 gene. | ||||||||
| 1188 | 34.27 | 15294912 | 2004.11.24 | + | + | Apc deficiency is associated with increased Egfr activity in the intestinal enterocytes and adenomas of C57BL/6J-Min/+ mice. | J Biol Chem | |
| AE Moran, DH Hunt, SH Javid, M Redston, AM Carothers, MM Bertagnolli, | ||||||||
| Overexpression of the epidermal growth factor receptor (EGFR) and its increased tyrosine kinase activity are implicated in colorectal cancer (CRC) development and malignant progression. The C57BL/6J-Min/+ (Min/+) mouse is a model for CRC and develops numerous intestinal adenomas. We analyzed the normal mucosa of Min/+ and Apc+/+ (WT) littermate mice together with Apc-null adenomas to gain insight into the roles of Egfr in these intestinal tissues. Protein analyses showed that Egfr activity was highest in the tumors, and also up-regulated in Min/+ relative to WT enterocytes. Expression of ubiquitylated Egfr (Egfr-Ub) was increased in Min/+ enterocytes and tumors. Tumors exhibited increased association of Egfr with clathrin heavy chain (CHC), Gab1, and p85alpha, the regulatory subunit of phosphoinositide 3-kinase (PI3K), and tumors also overexpressed c-Src, PDK1, and Akt. Immunohistochemistry for Akt-p-Ser473 revealed a low level of this active kinase in Min/+ and WT enterocytes and its strong presence in tumors. Prostaglandin E2 (PGE2) is a product of cyclooxygenase-2 (Cox-2) activity that is up-regulated in Min/+ tumors and transactivates Egfr. PGE2 expression was significantly higher in untreated Min/+ tumors and reduced by treatment with the Cox-2 inhibitor, celecoxib. Dietary administration of this NSAID also inhibited Egfr activity in tumors. Increased activation of the EGFR-PI3K-Akt signaling pathway in tumors relative to Apc+/+ and ApcMin/+ enterocytes provides potential opportunities for therapeutic interventions to differentially suppress tumor formation, promotion, progression, and/or recurrence. | ||||||||
| 1189 | 34.27 | 9544837 | 1998.04.24 | + | + | Multiple different missense mutations in the pore region of HERG in patients with long QT syndrome. | Hum Genet | |
| CA Satler, MR Vesely, P Duggal, GS Ginsburg, AH Beggs, | ||||||||
| Long QT syndrome (LQTS), is an inherited cardiac disorder in which ventricular tachyarrhythmias predispose affected individuals to syncope, seizures, and sudden death. Characteristic electrocardiographic findings include a prolonged QT interval, T wave alternans, and notched T waves. We have screened LQTS patients from 89 families for mutations in the pore region of HERG , the K+ channel gene previously associated with chromosome 7-linked LQT2. In six unrelated LQTS kindreds, single-strand conformation polymorphism analyses identified aberrant conformers in all affected family members. These conformers were not seen in over 100 unaffected, unrelated control individuals, suggesting that they represent pathogenic LQTS mutations. DNA sequence analyses of the aberrant conformers demonstrated that they reflect five different missense mutations: V612L, A614V, N629D, N629S, and N633S. The missense mutation A614V was found in two unrelated families. Further functional studies will be required to determine what effect each of these changes may have on HERG channel function. | ||||||||
| 1190 | 34.26 | 14715662 | 2004.05.07 | + | + | ESE-1 is a novel transcriptional mediator of angiopoietin-1 expression in the setting of inflammation. | J Biol Chem | |
| C Brown, J Gaspar, A Pettit, R Lee, X Gu, H Wang, C Manning, C Voland, SR Goldring, MB Goldring, TA Libermann, EM Gravallese, P Oettgen, | ||||||||
| Angiogenesis is a critical component of the inflammatory response associated with a number of conditions. Angiopoietin-1 (Ang-1) is an angiogenic growth factor that promotes the chemotaxis of endothelial cells and facilitates the maturation of new blood vessels. Ang-1 expression is up-regulated in response to tumor necrosis factor-alpha (TNF-alpha). To begin to elucidate the underlying molecular mechanisms by which Ang-1 gene expression is regulated during inflammation, we isolated 3.2 kb of the Ang-1 promoter that contain regulatory elements sufficient to mediate induction of the promoter in response to TNF-alpha, interleukin-1beta, and endotoxin. Surprisingly, sequence analysis of this promoter failed to reveal binding sites for transcription factors that are frequently associated with mediating inflammatory responses, such as NF-kappaB, STAT, NFAT, or C/EBP. However, putative binding sites for ETS and AP-1 transcription factor family members were identified. Interestingly, among a panel of ETS factors tested in a transient transfection assay, only the ETS factor ESE-1 was capable of transactivating the Ang-1 promoter. ESE-1 binds to specific ETS sites within the Ang-1 promoter that are functionally important for transactivation by ESE-1. ESE-1 and Ang-1 are induced in synovial fibroblasts in response to inflammatory cytokines, with ESE-1 induction slightly preceding that of Ang-1. Mutation of a high-affinity ESE-1 binding site leads to a marked reduction in Ang-1 transactivation by ESE-1, inducibility by inflammatory cytokines, and DNA binding to the ESE-1 protein. Transcriptional profiling of cells transiently transfected with an ESE-1 expression vector demonstrates that the endogenous Ang-1 gene is directly inducible by ESE-1. Finally, Ang-1 and ESE-1 exhibit a similar and strong expression pattern in the synovium of patients with rheumatoid arthritis. Our results support a novel paradigm for the ETS factor ESE-1 as a transcriptional mediator of angiogenesis in the setting of inflammation. | ||||||||
| 1191 | 34.26 | 15889417 | 2005.07.05 | + | + | Relationship between polymorphisms in genes involved in homocysteine metabolism and maternal risk for Down syndrome in Brazil. | Am J Med Genet A | |
| LR da Silva, N Vergani, Lde C Galdieri, MP Ribeiro Porto, SB Longhitano, D Brunoni, V D'Almeida, AB Alvarez Perez, | ||||||||
| Associations between specific alleles of genes encoding enzymes in the methionine/homocysteine pathway and plasma homocysteine levels have been examined in different populations. In the present study, we determined polymorphisms of MTHFR A222V (677C > T), MTHFR E429A (1298A > C), MTRR I22M (66A > G), MTR D919G (2756A > G), and CBS 844ins68 and total plasma homocysteine levels (tHcy) among 154 mothers of children with Down syndrome (DS) and 158 control mothers from Brazil. Homocysteine levels were higher among DS mothers compared to control groups (10.437 vs. 8.600 respectively, P = 0.002). Only the 677T allele was associated with altered levels of tHcy in the case group (F((2,153)) = 5.300; P = 0.006), primarily when homozygous. In the control group, the association of the TT genotype with higher levels of tHcy showed borderline significance (F((2,157)) = 2.974; P = 0.054). All genotype distributions were similar in the two groups (P > 0.05), but the frequency of the 677T allele in the case group was significantly higher (chi(2) = 3.862; DF = 1; P = 0.049; OR = 1.437 (1.001-2.062)). Although the 677T allele is associated with increased homocysteine levels, its presence has only a modest impact as an independent risk factor for DS. All the other polymorphisms did not show an association with risk for the syndrome, when evaluated separately (P > 0.05). However, when the presence of 677T, 1298C, 2756G, 66G, and 844ins68 alleles were evaluated together, the mothers of children with DS tend to have a higher number of uncommon alleles than the mothers with no previous affected child. | ||||||||
| 1192 | 34.25 | 15533655 | 2005.03.01 | + | + | A major influence of CYP2C19 genotype on the steady-state concentration of N-desmethylclobazam. | Brain Dev | |
| K Kosaki, K Tamura, R Sato, H Samejima, Y Tanigawara, T Takahashi, | ||||||||
| N-desmethylclobazam (N-CLB), the major metabolite of clobazam (CLB), exerts a large influence on therapeutic and adverse effects of CLB. A substantial inter-individual variability has been observed in the ratios of N-CLB concentration/CLB dose and of the N-CLB/CLB concentration. We document here a genotype-phenotype correlation between CYP2C19 polymorphisms and those ratios. Patients with two mutated CYP2C19 alleles show significantly higher ratios than those with the wild type genotype: patients with one mutated allele exhibited intermediate trait. That is, the degree of elevation in the ratios was dependent on the number of mutated alleles of CYP2C19 (gene-dose effect). The N-CLB concentration/CLB dose ratio of patients with two mutated alleles was more than six fold higher than that of wild type patients. Thus, the serum N-CLB/CLB concentration ratio may be a valuable parameter to screen for patients at risk for side effects. Such precautions may be clinically relevant in populations where the mutant allele frequency is high, such as in Asian populations ( approximately 35%). Patients co-medicated with CYP3A4 inducer showed lower CLB concentration/CLB dose ratios and higher N-CLB/CLB concentration ratios. The overall effect of CYP3A4 inducer on N-CLB metabolism, however, was small and, thus, we conclude that the CYP2C19 genotype is the major determinant of the N-CLB concentration. For this reason it is crucial for the better management of epilepsy and other chronic illnesses in general to establish the correlation of genotype of CYP enzymes and pharmacokinetics/dynamics of drugs. | ||||||||
| 1193 | 34.25 | 12010862 | 2002.06.14 | + | + | XRCC1 and CYP2E1 polymorphisms as susceptibility factors of plasma mutant p53 protein and anti-p53 antibody expression in vinyl chloride monomer-exposed polyvinyl chloride workers. | Cancer Epidemiol Biomarkers Prev | |
| RH Wong, CL Du, JD Wang, CC Chan, JC Luo, TJ Cheng, | ||||||||
| Mutant p53 protein and anti-p53 antibody in circulating blood can be detectedamong individuals with mutations of the p53 tumor suppressor gene. Plasma mutant p53 protein and anti-p53 antibody have also been associated with vinyl chloride monomer (VCM) exposure, although the mechanism of VCM-related carcinogenesis remains unclear. Polymorphisms of metabolic and DNA repair genes have been implicated in chemical exposure-related carcinogenesis. The aim of this study is to explore the association between polymorphisms of metabolic and DNA repair genes with mutant p53 protein and anti-p53 antibody expression induced by VCM. Study subjects comprised 333 male workers occupationally exposed to VCM. Plasma mutant p53 protein and anti-p53 antibody detected with ELISA were grouped together as p53 overexpression. Genotypes of cytochrome P450 2E1 (CYP2E1), aldehyde dehydrogenase 2 (ALDH2), glutathione S-transferase T1 (GSTT1), and X-ray repair cross-complementing group 1 (XRCC1, exon 10) genes were identified by the PCR. High VCM exposure group had significantly higher p53 overexpression as compared with low exposure group [odds ratio (OR), 2.1; 95% confidence interval (CI), 1.1-3.8]. Individuals having experienced a high VCM exposure and displaying a XRCC1 Gln-Gln genotype had a highest risk of p53 overexpression among those having different combinations of VCM exposure and XRCC1 genotypes (OR, 6.5; 95% CI, 1.7-24.2). Interestingly, those subjects reflecting a CYP2E1 c2c2 genotype among the low VCM-exposure group demonstrated a greater risk of p53 overexpression (OR, 9.8; 95% CI, 1.2-81.6) as compared with those experiencing a low VCM exposure and CYP2E1 c1c1/c1c2 genotypes. Additional analysis revealed that individuals possessing more susceptible XRCC1 Gln-Gln, CYP2E1 c2c2, ALDH2 1-2/2-2, and non-null GSTT1 genotypes were more likely to reveal p53 overexpression. Our results suggest that susceptible XRCC1 and CYP2E1 genotypes may modulate the mutation of the p53 gene among VCM-exposed workers. | ||||||||
| 1194 | 34.25 | 11907488 | 2002.04.23 | + | + | Low daily 10-mg and 20-mg doses of fluvoxamine inhibit the metabolism of both caffeine (cytochrome P4501A2) and omeprazole (cytochrome P4502C19). | Clin Pharmacol Ther | |
| M Christensen, G Tybring, K Mihara, N Yasui-Furokori, JA Carrillo, SI Ramos, K Andersson, ML Dahl, L Bertilsson, | ||||||||
| OBJECTIVES: Fluvoxamine is metabolized by the polymorphic cytochrome P450 (CYP) 2D6 and the smoking-inducible CYP1A2. Therapeutic doses of fluvoxamine inhibit both CYP1A2 and CYP2C19. In this study we used extensive metabolizers (EMs) and poor metabolizers (PMs) of debrisoquin (INN, debrisoquine) (CYP2D6) and two probes, caffeine (CYP1A2) and omeprazole (CYP2C19), to investigate whether nontherapeutic doses of fluvoxamine inhibit CYP1A2 but possibly not CYP2C19. METHODS: Single oral doses of 100 mg caffeine and 20 mg omeprazole were given separately to 5 EMs and 5 PMs of debrisoquin to assess the activity of CYP1A2 and CYP2C19, respectively. Initially, a single oral dose of fluvoxamine (25 mg to PMs and 50 mg to EMs) was given, followed by 1 week of daily administration of 25 mg x 2 to EMs and 25 mg x 1 to PMs. Caffeine (day 6) and omeprazole (day 7) were again administered at the steady state of fluvoxamine. Later the study protocol was repeated with a lower dose of fluvoxamine, 10 mg x 2 to EMs and 10 mg x 1 to PMs for 1 week. Concentrations of fluvoxamine, caffeine, omeprazole, and their metabolites were analyzed by HPLC methods in plasma and urine. RESULTS: The kinetics of fluvoxamine were not significantly different in EMs and PMs after a single oral dose of the drug. At the higher but not the lower steady-state dose of fluvoxamine, a significantly lower clearance in PMs compared with EMs was observed (geometric mean, 0.86 versus 1.4 L/h per kilogram; P <.05). At steady state, the 25 mg x 1 or x 2 fluvoxamine dose caused a pronounced inhibition of about 75% to 80% for both CYP1A2 and CYP2C19, whereas the inhibition after the lower 10 mg x 1 or x 2 dose was about 40% to 50%. The area under the plasma concentration-versus-time curve from 0 to 24 hours [AUC(0-24)] of caffeine increased 5-fold (P <.001) after the higher dose of fluvoxamine and 2-fold (P <.05) after the lower dose. The area under the plasma concentration-time curve from time zero to 8 hours [AUC(0-8)] ratio of 5-hydroxyomeprazole/omeprazole decreased 3.4-fold (P <.001) and 2.4-fold (P <.001), respectively. One EM subject had a very low oral clearance of fluvoxamine after both single and multiple dosing of the drug. This subject might have a deficient transporter protein in the gut, leading to an increased absorption of fluvoxamine. CONCLUSION: No convincing evidence was found that CYP2D6 is an important enzyme for the disposition of fluvoxamine. Other factors seem to be more important. A nontherapeutic oral daily dose of fluvoxamine is sufficient to provide a marked inhibition of both caffeine (CYP1A2) and omeprazole (CYP2C19) metabolism. It was not possible to separate the inhibitory effects of fluvoxamine on these enzymes, even after such a low daily dose such as 10 mg x 1 or x 2 of fluvoxamine. | ||||||||
| 1195 | 34.24 | 10383893 | 1999.08.24 | + | + | Genetic polymorphism of CYP2D6, GSTM1 and NAT2 and susceptibility to haematological neoplasias. | Carcinogenesis | |
| MC Lemos, FJ Cabrita, HA Silva, M Vivan, F Plácido, FJ Regateiro, | ||||||||
| Xenobiotic-metabolizing enzymes constitute an important line of defence against a variety of carcinogens. Many are polymorphic, constituting the basis for the wide inter-individual variation in metabolic capacity and possibly a source of variation in the susceptibility to chemical-induced carcinogenesis. The aim of this study was to determine the existence of any association between the main genetic polymorphisms of cytochrome P450 2D6 (CYP2D6), glutathione S-transferase M1 (GSTM1) and N-acetyltransferase 2 (NAT2) and an altered risk for haematological neoplasias. A total of 160 patients and 128 controls were genotyped by means of PCR-RFLP-based assays. Mutated alleles comprising CYP2D6*4, GSTM1*0, NAT2*5A, *5B, *5C, *6 and *7 were analysed along with the wild-type alleles. The results showed a higher frequency of CYP2D6 extensive metabolizers carrying two functional alleles in the leukaemia group, when compared with controls (76.6 versus 57.0%, P = 0.008). No differences were found in the case of Hodgkin and non-Hodgkin lymphomas. Analysis of the GSTM1 and NAT2 polymorphisms failed to show an association with any of the neoplasias, although a near significant increase in fast acetylators was also found in the leukaemia group (50.0 versus 35.9%, P = 0.06). The results suggest an association of extensive metabolism with an increased risk for leukaemia, possibly by an increase in the metabolic activation of chemical carcinogens or linkage to another cancer-causing gene. Opposite findings presented in other studies may reflect geographical differences in the type of environmental carcinogens to which different populations are exposed. | ||||||||
| 1196 | 34.23 | 16162969 | 2005.12.16 | + | + | Genetic determinants of cancer drug efficacy and toxicity: practical considerations and perspectives. | Anticancer Drugs | |
| M Candelaria, L Taja-Chayeb, C Arce-Salinas, S Vidal-Millan, A Serrano-Olvera, A Dueñas-Gonzalez, | ||||||||
| Drug-metabolizing enzymes are responsible for the activation or detoxification of cytotoxic drugs. Allelic variants are present with a variable frequency in different populations around the world and have an important role in the therapeutic index of such drugs. It is known that polymorphisms in thiopurine methyltransferase and dihydropyrimidine dehydrogenase have been associated with altered drug metabolism and increased risk of severe toxicity from 6-mercaptopurine and 5-fluorouracil, respectively. Additionally, a variant number of dinucleotide-repeat sequences in the promotor for uridine 5'-diphosphate glucuronosyltransferase 1A1 influences the glucuronidation of SN-38, the active metabolite of irinotecan, which is associated with severe toxicity, including diarrhea and neutropenia. In the same way, polymorphisms in thymidylate synthase have been associated with pyrimidine-associated toxicity and also with response to chemotherapy. The examples shown in this review demonstrate the usefulness of pre-screening patients for well-characterized polymorphism to identify the best-tolerated and most-effective treatment. | ||||||||
| 1197 | 34.23 | 12654968 | 2004.01.12 | + | + | Strong association between N-acetyltransferase 2 genotype and PD in Hong Kong Chinese. | Neurology | |
| DK Chan, MK Lam, R Wong, WT Hung, DE Wilcken, | ||||||||
| BACKGROUND: The slow acetylator genotype for N-acetyltransferase 2 (NAT2 genotype) may be associated with PD in white subjects and the genotype is common in both white and Chinese populations. Whether there is a relationship between NAT2 genotype and PD in Chinese subjects is not known. OBJECTIVE: To investigate the association between the slow acetylator genotype for N-acetyltransferase 2 and PD in a Chinese population. METHODS: The authors obtained DNA samples and documented sex, age, and smoking history in 99 Chinese patients with PD and in 126 control subjects from two major Hong Kong hospitals. PCR-restriction fragment length polymorphism was used to identify M1, M2, and M3 mutant polymorphisms of the slow acetylator genotype for N-acetyltransferase 2. Logistic regression analyses were carried out to investigate the relationships between the different variables and PD. RESULTS: The frequency of the slow acetylator genotype for N-acetyltransferase 2 in the PD group was significantly higher than that of the control group (68.7% vs 28.6%) with an OR of 5.53 (95% CI 3.08 to 9.92) after adjusting for age, sex, and smoking history. In a subgroup analysis smoking had no modifying effect on the association between genotype and PD. CONCLUSIONS: There is a significant association between PD and the slow acetylator genotype for N-acetyltransferase 2 in Hong Kong Chinese. The OR found is among the highest reported so far in all susceptibility gene studies for PD in both Chinese and white subjects and provides evidence for a possible functional relationship between NAT2 slow acetylator genotype and PD in both racial groups. | ||||||||
| 1198 | 34.22 | 11266076 | 2001.06.14 | + | + | Genomic organization of the human CYP3A locus: identification of a new, inducible CYP3A gene. | Pharmacogenetics | |
| K Gellner, R Eiselt, E Hustert, H Arnold, I Koch, M Haberl, CJ Deglmann, O Burk, D Buntefuss, S Escher, C Bishop, HG Koebe, U Brinkmann, HP Klenk, K Kleine, UA Meyer, L Wojnowski, | ||||||||
| Proteins encoded by the human CYP3A genes metabolize every second drug currently in use. The activity of CYP3A gene products in the general population is highly variable and may affect the efficacy and safety of drugs metabolized by these enzymes. The mechanisms underlying this variability are poorly understood, but they include gene induction, protein inhibition and unknown genetic polymorphisms. To better understand the regulation of CYP3A expression and to provide a basis for a screen of genetic polymorphisms, we determined and analysed the sequence of the human CYP3A locus. The 231 kb locus sequence contains the three CYP3A genes described previously (CYP3A4, CYP3A5 and CYP3A7), three pseudogenes as well as a novel CYP3A gene termed CYP3A43. The gene encodes a putative protein with between 71.5% and 75.8% identity to the other CYP3A proteins. The highest expression level of CYP3A43 mRNA is observed in the prostate, an organ with extensive steroid metabolism. CYP3A43 is also expressed in several other tissues including liver, where it can be induced by rifampicin. CYP3A43 transcripts undergo extensive splicing. The identification of a new member of the CYP3A family and the characterization of the full CYP3A locus will aid efforts to identify the genetic variants underlying its variable expression. This, in turn, will lead to a better optimization of therapies involving the numerous substrates of CYP3A proteins. | ||||||||
| 1199 | 34.20 | 15705354 | 2005.05.09 | + | + | A family-based association study and gene expression analyses of netrin-G1 and -G2 genes in schizophrenia. | Biol Psychiatry | |
| M Aoki-Suzuki, K Yamada, J Meerabux, Y Iwayama-Shigeno, H Ohba, K Iwamoto, H Takao, T Toyota, Y Suto, N Nakatani, B Dean, S Nishimura, K Seki, T Kato, S Itohara, T Nishikawa, T Yoshikawa, | ||||||||
| BACKGROUND: The netrin-G1 (NTNG1) and -G2 (NTNG2) genes, recently cloned from mouse, play a role in the formation and/or maintenance of glutamatergic neural circuitry. Accumulating evidence strongly suggests that disturbances of neuronal development and the N-methyl-d-aspartate receptor-mediated signaling system might represent a potential pathophysiology in schizophrenia. We therefore set out to examine the genetic contribution of human NTNG1 and NTNG2 to schizophrenia. METHODS: Twenty-one single nucleotide polymorphisms (SNPs) from NTNG1 and 10 SNPs from NTNG2 were analyzed in 124 schizophrenic pedigrees. All genotypes were determined with the TaqMan assay. The expression levels of NTNG1 and NTNG2 were examined in the frontal (Brodmann's Area [BA]11 and BA46) and temporal (BA22) cortices from schizophrenic and control postmortem brains. The isoform-specific expression of NTNG1 splice variants was assessed in these samples. RESULTS: Specific haplotypes encompassing alternatively spliced exons of NTNG1 were associated with schizophrenia, and concordantly, messenger ribonucleic acid isoform expression was significantly different between schizophrenic and control brains. An association between NTNG2 and schizophrenia was also observed with SNPs and haplotypes that clustered in the 5' region of the gene. CONCLUSIONS: The NTNG1 and NTNG2 genes might be relevant to the pathophysiology of schizophrenia. | ||||||||
| 1200 | 34.20 | 11742872 | 2002.01.03 | + | + | Genome-wide linkage analysis of lipids in the Hypertension Genetic Epidemiology Network (HyperGEN) Blood Pressure Study. | Arterioscler Thromb Vasc Biol | |
| H Coon, MF Leppert, JH Eckfeldt, A Oberman, RH Myers, JM Peacock, MA Province, PN Hopkins, G Heiss, | ||||||||
| Full genome scans were performed for quantitative lipid measurements in 622 African American and 649 white sibling pairs not taking lipid-lowering medications who were ascertained through the Hypertension Genetic Epidemiology Network (HyperGEN) of the National Heart, Lung, and Blood Institute (NHLBI) Family Blood Pressure Program. Genotypes for 391 markers spaced roughly equally throughout the genome were typed by the NHLBI Mammalian Genotyping Service. Each of the phenotypes was adjusted for covariates within sex and race and then subjected to variance components linkage analysis, which was performed separately within race by using race-specific marker allele frequencies from additional random samples. The highest lod score detected was 2.77 for logarithmically transformed triglyceride (TG) on chromosome 20 (at 28.6 cM) in the African American sibling pairs. The highest score detected in the white sibling pairs was 2.74 for high density lipoprotein cholesterol on chromosome 5 (at 48.2 cM). Although no scores >3.0 were obtained, positive scores were found in several regions that have been reported in other genome scans in the literature. For example, a score of 1.91 for TG was found on chromosome 15 (at 28.8 cM) in white sibling pairs. This score overlaps the positive findings for TG in 2 other genome scans. | ||||||||
| 1201 | 34.20 | 9551703 | 1998.06.02 | + | + | Fluconazole but not itraconazole decreases the metabolism of losartan to E-3174. | Eur J Clin Pharmacol | |
| KM Kaukonen, KT Olkkola, PJ Neuvonen, | ||||||||
| OBJECTIVE: Losartan is metabolised to its active metabolite E-3174 by CYP2C9 and CYP3A4 in vitro. Itraconazole is an inhibitor of CYP3A4, whereas fluconazole affects CYP2C9 more than CYP3A4. We wanted to study the possible interaction of these antimycotics with losartan in healthy volunteers. METHODS: A randomised, double-blind, three-phase crossover study design was used. Eleven healthy volunteers ingested orally, once a day for 4 days, either itraconazole 200 mg, fluconazole (400 mg on day 1 and 200 mg on days 2-4) or placebo (control). On day 4, a single 50-mg oral dose of losartan was ingested. Plasma concentrations of losartan, E-3174, itraconazole, hydroxy-itraconazole and fluconazole were determined over 24 h. The blood pressure and heart rate were also recorded over 24 h. RESULTS: The mean peak plasma concentration (Cmax) and area under the curve [AUC(0-infinity)] of E-3174 were significantly decreased by fluconazole to 30% and to 47% of their control values, respectively, and the t1/2 was increased to 167%. Fluconazole caused only a nonsignificant increase (23-41%) in the AUC and t1/2 of the unchanged losartan. Itraconazole had no significant effect on the pharmacokinetic variables of losartan or E-3174. The ratio AUC(0-infinity)(E-3174)/AUC(0-infinity)losartan was 60% smaller during the fluconazole than during the placebo and itraconazole phases. No clinically significant changes in the effects of losartan on blood pressure and heart rate were observed between fluconazole, itraconazole and placebo phases. CONCLUSION: Fluconazole but not itraconazole interacts with losartan by inhibiting its metabolism to the active metabolite E-3174. This implicates that, in man, CYP2C9 is a major enzyme for the formation of E-3174 from losartan. The clinical significance of the fluconazole losartan interaction is unclear, but the possibility of a decreased therapeutic effect of losartan should be kept in mind. | ||||||||
| 1202 | 34.20 | 15351693 | 2004.11.23 | + | + | TRIM45, a novel human RBCC/TRIM protein, inhibits transcriptional activities of ElK-1 and AP-1. | Biochem Biophys Res Commun | |
| Y Wang, Y Li, X Qi, W Yuan, J Ai, C Zhu, L Cao, H Yang, F Liu, X Wu, M Liu, | ||||||||
| The tripartite motif (TRIM) proteins play important roles in a variety of cellular functions including cell proliferation, differentiation, development, oncogenesis, and apoptosis. In this study, we report the identification and characterization of the human tripartite motif-containing protein 45 (TRIM45), a novel member of the TRIM family, from a human embryonic heart cDNA library. TRIM45 has a predicted 580 amino acid open reading frame, encoding a putative 64-kDa protein. The N-terminal region harbors a RING finger, two B-boxes, and a predicted alpha-helical coiled-coil domain, which together form the RBCC/TRIM motif found in a large family of proteins, whereas the C-terminal region contains a filamin-type immunoglobulin (IG-FLMN) domain. Northern blot analysis indicates that TRIM45 is expressed in a variety of human adult and embryonic tissues. In the cell, TRIM45 protein is expressed both in cytoplasm and in cell nucleus. Overexpression of TRIM45 in COS-7 cells inhibits the transcriptional activities of ElK-1 and AP-1. These results suggest that TRIM45 may act as a new transcriptional repressor in mitogen-activated protein kinase signaling pathway. | ||||||||
| 1203 | 34.20 | 11896615 | 2002.04.09 | + | + | Alternative transcripts of the candidate tumor suppressor gene, WWOX, are expressed at high levels in human breast tumors. | Oncogene | |
| K Driouch, H Prydz, R Monese, H Johansen, R Lidereau, E Frengen, | ||||||||
| The presence of putative tumor-suppressor genes on chromosome 16q23.2-24.1 has been suggested by LOH analysis in several cancer types. This region overlaps with the fragile site FRA16D and the region of homozygous deletions found in several cancer types. The candidate gene WWOX/FOR has been mapped within this region. The mouse homologue of the WWOX protein has been defined as an apoptogenic protein and an essential partner of p53 in cell death, supporting WWOX as a tumor suppressor gene candidate. We performed an expression study of the WWOX/FOR gene in a series of human breast tumors and breast cancer cell lines, and detected reduced expression of the WWOX/FOR transcript in a series of breast cancer cells. Furthermore, identification of two distinct alternative WWOX transcripts expressed at high levels in human tumors suggests an involvement of the WWOX gene in breast cancer progression. | ||||||||
| 1204 | 34.19 | 12849668 | 2003.08.06 | + | + | Modulating effects of age and gender on the clinical course of long QT syndrome by genotype. | J Am Coll Cardiol | |
| W Zareba, AJ Moss, EH Locati, MH Lehmann, DR Peterson, WJ Hall, PJ Schwartz, GM Vincent, SG Priori, J Benhorin, JA Towbin, JL Robinson, ML Andrews, C Napolitano, K Timothy, L Zhang, A Medina, | ||||||||
| OBJECTIVES: We aimed to determine whether long QT syndrome (LQTS) genotype has a differential effect on clinical course of disease in male and female children and adults after adjustment for QTc duration. BACKGROUND: Genotype influences clinical course of the LQTS; however, data on the effect of age and gender on this association are limited. METHODS: The LQTS genotype, QTc duration, and follow-up were determined in 243 cases of LQTS caused by the KCNQ1 potassium channel gene mutations (LQT1), 209 cases of LQTS caused by the HERG potassium channel gene mutations (LQT2), and 81 cases of LQTS caused by the SCN5A sodium channel gene mutation (LQT3) gene carriers. The probability of cardiac events (syncope, aborted cardiac arrest, or sudden death) was analyzed by genotype, gender, and age (children < or = 15 years and adults 16 to 40 years). In addition, the risk of sudden death and lethality of cardiac events were evaluated in 1,075 LQT1, 976 LQT2, and 324 LQT3 family members from families with known genotype. RESULTS: During childhood, the risk of cardiac events was significantly higher in LQT1 males than in LQT1 females (hazard ratio [HR] = 1.72), whereas there was no significant gender-related difference in the risk of cardiac events among LQT2 and LQT3 carriers. During adulthood, LQT2 females (HR = 3.71) and LQT1 females (HR = 3.35) had a significantly higher risk of cardiac events than respective males. The lethality of cardiac events was highest in LQT3 males and females (19% and 18%), and higher in LQT1 and LQT2 males (5% and 6%) than in LQT1 and LQT2 females (2% for both). CONCLUSIONS; Age and gender have different, genotype-specific modulating effects on the probability of cardiac events and electrocardiographic presentation in LQT1 and LQT2 patients. | ||||||||
| 1205 | 34.18 | 10340921 | 1999.05.27 | + | + | CYP2C19 genotype status and effect of omeprazole on intragastric pH in humans. | Clin Pharmacol Ther | |
| T Furuta, K Ohashi, K Kosuge, XJ Zhao, M Takashima, M Kimura, M Nishimoto, H Hanai, E Kaneko, T Ishizaki, | ||||||||
| OBJECTIVE: Omeprazole is metabolized by genetically determined S-mephenytoin 4'-hydroxylase (CYP2C19) in the liver. This study aimed to determine whether the effect of omeprazole on intragastric pH depends on CYP2C19 genotype status. METHODS: CYP2C19 genotype status for 2 mutations associated with the poor metabolizer phenotype was determined by a polymerase chain reaction-restriction fragment length polymorphism method in 16 healthy volunteers. Helicobacterpylori status was determined by serology and the [13C]urea breath test. After a single oral administration of 20 mg omeprazole or a placebo, intragastric pH values were recorded for 24 hours. Plasma levels of omeprazole and its 2 metabolites and gastrin were measured before and 1, 2, 3, 5, 7, 10, and 24 hours after administration. RESULTS: Fifteen of the 16 subjects were H pylori negative. Five of the 15 subjects were homozygous extensive metabolizers, 4 were heterozygous extensive metabolizers, and 6 were poor metabolizers. After omeprazole administration, significant differences in mean intragastric pH values and plasma levels of gastrin, omeprazole and its metabolites were observed among the 3 groups, whereas no significant differences in these parameters were observed with the placebo administration. CONCLUSIONS: The effect of omeprazole on intragastric pH significantly depends on CYP2C19 genotype status. The genotyping test of CYP2C19 may be useful for an optimal prescription of omeprazole. | ||||||||
| 1206 | 34.18 | 11359462 | 2001.07.26 | + | + | APOC3, CETP, fibrinogen, and MTHFR are genetic determinants of carotid intima-media thickness in healthy men (the Stanislas cohort). | Clin Genet | |
| C Pallaud, C Sass, F Zannad, G Siest, S Visvikis, | ||||||||
| The purpose of this study was to examine the relationship between carotid intima-media thickness (CIMT) inter-individual variability and 16 polymorphisms of 11 genes associated with cardiovascular risk factors (genes among lipid and homocysteine metabolisms, blood viscosity, platelet aggregation, leukocyte adhesion and renin-angiotensin system). CIMT was measured by high resolution B-mode ultrasonography in an healthy population of 77 men and 84 women, aged 35-54 years and selected from a French Cohort: the Stanislas Cohort. The polymorphisms studied were genotyped by a multilocus approach. Statistical analyses were carried out by ANOVA, after adjustment of CIMT for age, body mass index, and smoking, and by multiple regression analyses. No association was found with APOB Thr71Ile, APOC3 -482C/T, -455T/C, GpIIIa P1A, AT1R 1166A/C, AGT Met235Thr, CBS Ile278Thr, SELE 98G/T, and SELE Ser128Arg, polymorphisms neither in men nor in women. Although, in women we did not find any association for APOC3 3206T/G, 3175C/G, 1100C/T, CETP Ile405Val, MTHFR 677C/T and fibrinogen -455G/A polymorphisms; in men these polymorphisms were associated with CIMT variability (p< or =0.01; p< or =0.05). The most interesting finding was that altogether these genes in men were able to explain a considerable part, 20.6%, of CIMT variability. Therefore, our study gives a new opportunity to understand CIMT variability. | ||||||||
| 1207 | 34.17 | 15748779 | 2005.05.20 | + | + | The association between promoter polymorphism of the interleukin-10 gene and Alzheimer's disease. | Neurobiol Aging | |
| SL Ma, NL Tang, LC Lam, HF Chiu, | ||||||||
| The importance of the role of inflammation has been suggested in the pathogenesis of Alzheimer's disease (AD). Interleukin-10 (IL-10) is an anti-inflammatory cytokine that may modulate the progression of the disease through the inhibition of the action of pro-inflammatory cytokines. In this study, three polymorphisms in the regulatory region of the IL-10 gene (-1082, -819 and -592) in 95 Chinese AD patients and 117 age-matched healthy Chinese subjects were investigated. We found that among the Chinese population, the A and C alleles at the -592 position are strongly linked to the T and C alleles at the -819 position, respectively. A strong association with AD was found for these two IL-10 polymorphisms, which are in complete linkage disequilibrium (-592C and -819C), and the odds ratio of AD is 4.03 (95% CI 1.23-13.23; p = 0.011). The functional significance of the IL-10 genotype was further supported by the significant association between plasma IL-10 concentrations and genotypes that were found in an independent sample of 160 healthy male volunteers. No interaction effect between the ApoE and IL-10 genotypes is found. Therefore, we concluded that the functional polymorphisms of the IL-10 gene act as a risk factor for AD. | ||||||||
| 1208 | 34.17 | 9341873 | 1997.11.19 | + | + | Autosomal recessive long-QT syndrome (Jervell Lange-Nielsen syndrome) is genetically heterogeneous. | Hum Genet | |
| E Schulze-Bahr, W Haverkamp, H Wedekind, C Rubie, M Hördt, M Borggrefe, G Assmann, G Breithardt, H Funke, | ||||||||
| Jervell Lange-Nielsen syndrome (JLNS) is a recessive disorder with congenital deafness and long-QT syndrome (LQTS 1). Mutations in the potassium-channel gene KVLQT1 (LQTS 1) have been identified in JLNS and in autosomal-dominant LQTS as well. We performed haplotype analysis with microsatellite markers in a Lebanese family with JLNS, but failed to detect linkage at LQTS 1. Moreover, using this approach, we excluded two other ion-channel genes involved in autosomal-dominant LQTS, HERG (LQTS 2) and SCN5A (LQTS 3). Our findings indicate that JLNS is genetically heterogeneous and that, in this family, an unknown LQTS gene causes the disease. | ||||||||
| 1209 | 34.16 | 12012142 | 2002.11.26 | + | + | The role of CYP2C19 in amitriptyline N-demethylation in Chinese subjects. | Eur J Clin Pharmacol | |
| ZP Jiang, Y Shu, XP Chen, SL Huang, RH Zhu, W Wang, N He, HH Zhou, | ||||||||
| OBJECTIVE: To determine the role of cytochrome P(450) (CYP)2C19 in N-demethylation of amitriptyline (AT) in healthy Chinese subjects.METHODS: One hundred and one subjects were genotyped for CYP2C19 using polymerase chain reaction-restriction fragment length polymorphism analysis. Twelve unrelated adult men (19.7+/-0.6 years, 61.8+/-3.8 kg) were chosen and orally given a single dose of 50 mg AT, and the blood samples were drawn from a forearm vein at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 48, 72, and 96 h after AT administration. Plasma concentrations of AT and nortriptyline (NT) were determined using high-performance liquid chromatography with an ultraviolet detector.RESULTS: The mean area under the plasma concentration-time curve (AUC(AT)) of CYP2C19 poor metabolizers (PMs, n=6) was significantly higher than that of CYP2C19 extensive metabolizers (EMs, n=6) (2207+/-501 ng/ml x h(-1) vs 1596+/-406 ng/ml x h(-1), P<0.05). In contrast, the mean AUC(NT(0-)(infinity)()) of PMs was significantly lower than that of EMs (294+/-70 ng/ml x h(-1) vs 684+/-130 ng/ml x h(-1), P<0.0001). Other pharmacokinetic parameters such as clearance, half-life, maximum plasma concentration, and time to peak plasma concentration showed no significant difference between PMs and EMs (0.41+/-0.12 l /h x kg(-1) vs 0.50+/-0.15 l /h x kg(-1), 25.0+/-6.2 h vs 24.1+/-4.4 h, 96+/-25 ng/ml vs 75+/-27 ng/ml, 4.0+/-1.4 h vs 3.7+/-1.5 h, respectively).CONCLUSION: The genetic defects of CYP2C19 have a significant effect on AT pharmacokinetics, and CYP2C19 plays an important role in N-demethylation of AT in vivo at a clinically therapeutic dose. | ||||||||
| 1210 | 34.16 | 8564837 | 1996.03.05 | + | + | A smoking-dependent risk of coronary artery disease associated with a polymorphism of the endothelial nitric oxide synthase gene. | Nat Med | |
| XL Wang, AS Sim, RF Badenhop, RM McCredie, DE Wilcken, | ||||||||
| Endothelium-dependent vasodilatation is mediated by release of nitric oxide formed by constitutively expressed endothelial nitric oxide synthase (ecNOS). We explored the distribution of polymorphism ecNOS4a/b in 549 subjects with, and 153 without, coronary artery disease in relation to smoking. In current and ex-cigarette smokers, but not nonsmokers, there was a significant excess of homozygotes for the rare ecNOS4a allele in patients with severely stenosed arteries, compared with those with no or mild stenosis. This genotype was also associated with a history of myocardial infarction. This smoking-dependent excess coronary risk in ecNOS4a homozygotes is consistent with predisposition to endothelial dysfunction. | ||||||||
| 1211 | 34.16 | 12442272 | 2002.12.23 | + | + | D90A-SOD1 mediated amyotrophic lateral sclerosis: a single founder for all cases with evidence for a Cis-acting disease modifier in the recessive haplotype. | Hum Mutat | |
| MJ Parton, W Broom, PM Andersen, A Al-Chalabi, P Nigel Leigh, JF Powell, CE Shaw, | ||||||||
| More than 100 different heterozygous mutations in copper/zinc superoxide dismutase (SOD1) have been found in patients with amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease. Uniquely, D90A-SOD1 has been identified in recessive, dominant and apparently sporadic pedigrees. The phenotype of homozygotes is stereotyped with an extended survival, whereas that of affected heterozygotes varies. The frequency of D90A-SOD1 is 50 times higher in Scandinavia (2.5%) than elsewhere, though ALS prevalence is not raised there. Our earlier study indicated separate founders for recessive and dominant/sporadic ALS and we proposed a disease-modifying factor linked to the recessive mutation. Here we have doubled our sample set and employed novel markers to characterise the mutation's origin and localise any modifying factor. Linkage disequilibrium analysis indicates that D90A homozygotes and heterozygotes share a rare haplotype and are all descended from a single ancient founder (alpha 0.974) c.895 generations ago. Homozygotes arose subsequently only c.63 generations ago (alpha 0.878). Recombination has reduced the region shared by recessive kindreds to 97-265 kb around SOD1, excluding all neighbouring genes. We propose that a cis-acting regulatory polymorphism has arisen close to D90A-SOD1 in the recessive founder, which decreases ALS susceptibility in heterozygotes and slows disease progression. | ||||||||
| 1212 | 34.15 | 12835618 | 2004.04.14 | + | + | Characterization of multiple promoters in the human carboxylesterase 2 gene. | Pharmacogenetics | |
| MH Wu, P Chen, BF Remo, EH Cook, S Das, ME Dolan, | ||||||||
| Carboxylesterases are a broad class of enzymes important in the detoxification of many ester- or amide-bond containing xenobiotics. They also activate analgesics, anticancer prodrugs, and other biologically active compounds, such as cocaine and heroin. The objective of this work was to identify the CES2 gene structure, complex 5' untranslated regions and three potential promoters for the initiation of transcription in different human tissues. Using bioinformatics and progressive reverse transcriptase-polymerase chain reaction, we found that the 5' untranslated region is more than 1100 bases longer than previously reported. Rapid amplification of cDNA ends showed three distinctive transcription start sites at -74, -629 and -1187. DNA fragments upstream of each of the three transcription start sites were found to be transcriptionally active in HepG2 cells. The distal promoter is active in both orientations, suggesting its potential role in the transcription of another gene, CGI-128, located immediately upstream to the distal promoter in the opposite direction with respect to CES2. Hybridization analyses showed that CES2 is highly expressed in the heart, skeletal muscle, colon, spleen, kidney and liver, but considerably less expressed in fetal tissues (e.g. fetal heart, kidney, spleen, and liver) and cancer cells. It is also evident that the distal promoter is responsible for low level expression of the gene in many tissues, whereas the other two promoters are tissue specific. These findings shed some light on CES2 gene regulation, a gene important in the metabolism of many drugs. | ||||||||
| 1213 | 34.15 | 9519757 | 1998.04.07 | + | + | Identification and functional analysis of sulfonylurea receptor 1 variants in Japanese patients with NIDDM. | Diabetes | |
| Y Ohta, Y Tanizawa, H Inoue, T Hosaka, K Ueda, A Matsutani, VP Repunte, M Yamada, Y Kurachi, J Bryan, L Aguilar-Bryan, MA Permutt, Y Oka, | ||||||||
| The sulfonylurea receptor 1 (SUR1) is an essential regulatory subunit of the beta-cell ATP-sensitive K+ channel (K[ATP]). The possible role of SUR1 gene mutation(s) in the development of NIDDM remains controversial as both a positive association and negative linkage results have been reported. Therefore, we examined the SUR1 gene at the single nucleotide level with single strand conformation polymorphism analysis in 100 Japanese NIDDM patients. We identified a total of five amino acid substitutions and 17 silent mutations by examining all 39 exons of this gene. Two rare novel mutations, D811N in exon 20 and R835C in exon 21, were identified in the first nucleotide-binding fold (NBF), a functionally important region of SUR1, in one patient each, both heterozygotes. To analyze possible functional alterations, we reconstituted the mutant K(ATP) by coexpressing beta-cell inward rectifier (BIR) (Kir 6.2), a channel subunit of K(ATP), and mutant SUR1 in HEK293T and COS-7 cells. As demonstrated by the patch clamp technique and rubidium (Rb+) efflux studies, neither mutation alters the properties of channel activities. Two other rare missense mutations, R275Q in exon 6 and V560M in exon 12, were also identified. The R275Q substitution was not found in 67 control subjects, and V560M was present in three control subjects. Neither of these substitutions appeared to cosegregate with NIDDM in the probands' families. A previously reported S1370A substitution located in the second NBF was also common in the Japanese subjects (allelic frequency 0.37), and was found at an equal frequency in nondiabetic control subjects. In conclusion, SUR1 mutations impairing K(ATP) function do not appear to be major determinants of NIDDM susceptibility in Japanese. | ||||||||
| 1214 | 34.14 | 9037249 | 1997.03.20 | + | + | Variable contribution of cytochromes P450 2D6, 2C9 and 3A4 to the 4-hydroxylation of tamoxifen by human liver microsomes. | Biochem Pharmacol | |
| HK Crewe, SW Ellis, MS Lennard, GT Tucker, | ||||||||
| 4-Hydroxylation is an important pathway of tamoxifen metabolism because the product of this reaction is intrinsically 100 times more potent as an oestrogen receptor antagonist than is the parent drug. Although tamoxifen 4-hydroxylation is catalysed by human cytochrome P450 (CYP), data conflict on the specific isoforms responsible. The aim of this study was to define unequivocally the role of individual CYPs in the 4-hydroxylation of tamoxifen by human liver microsomes. Microsomes from each of 10 human livers catalysed the reaction [range = 0.6-2.9 pmol/mg protein/min (1 microM substrate concentration) and 6-25 pmol/mg protein/min (18 microM)]. Three of the livers with the lowest tamoxifen 4-hydroxylation activity were from genetically poor metabolisers with respect to CYP2D6. Inhibition of activity by quinidine (1 microM), sulphaphenazole (20 microM) and ketoconazole (2 microM), selective inhibitors of CYPs 2D6, 2C9 and 3A4, respectively, was 0-80%, 0-80% and 12-57%. The proportion of activity inhibited by quinidine correlated positively with total microsomal tamoxifen 4-hydroxylation activity (rs = 0.89, P < 0.01), indicating a major involvement of CYP2D6 in this reaction. Recombinant human CYPs 2D6, 2C9 and 3A4 but not CYPs 1A1, 1A2, 2C19 and 2E1 displayed significant 4-hydroxylation activity. Similar inhibition and correlation experiments confirmed that tamoxifen N-demethylation is catalysed predominantly by CYP3A4. These findings indicate that the 4-hydroxylation of tamoxifen is catalysed almost exclusively by CYPs 2D6, 2C9 and 3A4 in human liver microsomes. However, the marked between-subject variation in the contribution of these isoforms underlines the need to study metabolic reactions in a sufficient number of livers that are characterised with respect to a range of cytochrome P450 activities. | ||||||||
| 1215 | 34.14 | 7704034 | 1995.05.10 | + | + | Biochemistry and molecular biology of the human CYP2C subfamily. | Pharmacogenetics | |
| JA Goldstein, SM de Morais, | ||||||||
| The cytochromes P450 (CYP) are a superfamily of hemoproteins which metabolize foreign chemicals as well as a number of endogenous compounds such as steroids. The human CYP2C subfamily appears to principally metabolize a number of clinically used drugs. Four members of this subfamily have been identified in humans: CYP2C8, CYP2C9, CYP2C18, and CYP2C19. CYP2C9 is important in the metabolism certain of therapeutically used drugs including the anticoagulant drug warfarin and a number of nonsteroidal antiinflammatory drugs. A number of allelic variants of CYP2C9 exist in humans, but the effects of these allelic variants on metabolism in vivo remain to be determined. A well-characterized genetic polymorphism occurs in the 2C subfamily which is associated with the metabolism of the anticonvulsant drug mephenytoin. In population studies, individuals can be segregated into extensive and poor metabolizers of mephenytoin. Poor metabolizers are unable to 4'-hydroxylate the S-enantiomer of mephenytoin. There are marked interracial variations in the frequency of the poor metabolizer phenotype which represents 3-5% of Caucasians, but 18-23% of Oriental populations. The mechanism of this polymorphism has been recently elucidated. The enzyme responsible for S-mephenytoin metabolism has been shown to be CYP2C19, and two defects in the CYP2C19 gene have been described in poor metabolizers. The first defect, CYP2C19m1, consists of the creation of an aberrant splice site in exon 5. This defect accounts for approximately 75-85% of Caucasian and Japanese poor metabolizers. A second defect, CYP2C19m2, has been found only in Oriental populations and accounts for the remaining 25% of poor metabolizers in Japanese populations. The availability of genotyping tests for this polymorphism will enhance the assessment of the role of this pathway in clinical studies. | ||||||||
| 1216 | 34.14 | 16247070 | 2006.04.14 | + | + | Analysis of LRRK2 functional domains in nondominant Parkinson disease. | Neurology | |
| L Skipper, H Shen, E Chua, C Bonnard, P Kolatkar, LC Tan, RD Jamora, K Puvan, KY Puong, Y Zhao, R Pavanni, MC Wong, Y Yuen, M Farrer, JJ Liu, EK Tan, | ||||||||
| A comprehensive sequence analysis of 29 exons that code for the functional domains of LRRK2 in 160 nondominant Parkinson disease (PD) patients was performed. Novel variant screening in a further 470 sporadic PD patients and 630 controls revealed two novel variants (R1067Q and IVS33 + 6 T>A), which are likely to be pathogenic in five patients. One patient presented initially with a typical essential tremor phenotype, expanding the phenotypic spectrum of LRRK2 mutations. | ||||||||
| 1217 | 34.14 | 11932247 | 2002.04.26 | + | + | Complex SNP-based haplotypes in three human helicases: implications for cancer association studies. | Genome Res | |
| D Trikka, Z Fang, A Renwick, SH Jones, R Chakraborty, M Kimmel, DL Nelson, | ||||||||
| We have initiated a candidate gene approach to study variation and predisposition to cancer in the four major ethnic groups that constitute the U.S. population (African Americans, Caucasians, Hispanics, and Asians). We resequenced portions of three helicase genes (BLM, WRN, and RECQL) identifying a total of 37 noncoding single nucleotide polymorphisms (SNPs). Haplotype inference predicted 50 haplotypes in BLM, 56 in WRN, and 47 in RECQL in a sample of 600 chromosomes. Approximately 10% of the predicted haplotypes were shared among all ethnic groups. Linkage disequilibrium and recombination effects showed that each locus has taken a diverse evolutionary path. Primate DNA analysis of the same loci revealed one human haplotype per gene shared with the great apes, indicating that the observed diversity occurred since the divergence of humans from the last common ancestor. In BLM, we confirmed the presence of a founder haplotype among Ashkenazi Jews homozygous for the blm(Ash) mutation. The cosegregating haplotype was seen in all (6/6) samples of Ashkenazi descent, whereas in the general population it has a low frequency (0.02) and was not found in African Americans. In WRN, ethnic samples were studied for their haplotype content and the presence or absence of six previously described coding SNPs (cSNPs). Hispanic individuals carrying two of these cSNPs showed a 60% increase in the frequency of a common haplotype (haplotype No. 28). In the pooled sample, no association was found. Because (1) the majority of the haplotypes are population specific and (2) the patterns of linkage disequilibrium, recombination, and haplotype diversity are markedly different between gene regions, these data show the importance of either ethnically matched controls or within-family-based disease-gene association studies. | ||||||||
| 1218 | 34.13 | 7932410 | 1994.10.25 | + | + | Phenotype/genotype relationships for the cytochrome P450 enzyme CYP2D6 in rheumatoid arthritis: influence of drug therapy and disease activity. | J Rheumatol | |
| C Beyeler, AK Daly, M Armstrong, C Astbury, HA Bird, JR Idle, | ||||||||
| OBJECTIVE. To determine whether particular genotypes for the cytochrome P450 enzyme CYP2D6, a polymorphic enzyme, are associated with susceptibility to rheumatoid arthritis (RA) and whether CYP2D6 enzyme activity is altered as a result of the disease or its treatment. METHODS. CYP2D6 genotypes and metabolic phenotypes were determined for 53 patients with RA and 73 healthy controls. Genotyping was carried out by restriction fragment length polymorphism analysis with the restriction enzyme XbaI and by 2 separate polymerase chain reaction assays; phenotyping was by analysis of in vivo metabolism of the probe drug debrisoquin. RESULTS. No significant difference in the distribution of overall genotypes between the 2 groups was observed. When the frequency of individual alleles was investigated, a significant difference in allele frequency for the CYP2D6D allele (p < 0.005) was observed with fewer patients with RA showing this mutation. Metabolic phenotypes were broadly similar between the patients and controls. However, a number of the patients with RA showed higher than expected metabolic ratios for their particular genotype due to interference by the analgesic dextropropoxyphene in the phenotyping procedure. CONCLUSION. Our findings demonstrate that CYP2D6 activity is not impaired in RA. | ||||||||
| 1219 | 34.13 | 10752643 | 2000.06.02 | + | + | Ethnic-related differences in the frequency distribution of genetic polymorphisms in the CYP1A1 and CYP1B1 genes in Japanese and Caucasian populations. | Xenobiotica | |
| K Inoue, T Asao, T Shimada, | ||||||||
| 1. Race-related differences in the frequency distribution of genetic polymorphisms in the CYP1A1 and CYP1B1 genes were studied in 39 Japanese and 45 Caucasians. 2. Four types of CYP1A1 polymorphism, namely m1 (a nucleotide change at T6235C in the 3'-flanking region), m2 (A4889G at exon 7), m3 (T5639C in the 3'-flanking region) and m4 (C4887A at exon 7), and three types of CYP1B1 genetic polymorphism, namely m1 (C488G and G701T leading to Arg48Gly and Ala119Ser exchanges respectively), m2 (C1294G leading to a Leu432Val exchange) and m3 (A1358G leading to an Asn453Ser exchange) were studied. 3. The distribution of the m1-, m2-, m3-, and m4-types of CYP1A1 polymorphism in the Japanese population was 30.8, 17.9, 0 and 0% respectively; those in Caucasians were 3.3, 6.7, 0 and 2.2% respectively. Two types (m1, and m2) of CYP1B1 polymorphism were expressed at 14.1 and 21.8% respectively in the Japanese, and by 28.9 and 37.5% respectively in the Caucasian. Ethnic differences were also noted in the m3-type CYP1B1 polymorphism in which the incidence in Caucasians was 23.9%, whereas no cases in the 39 Japanese subjects were observed. 4. No apparent association was found in the incidence in each of the genetic polymorphisms of CYP1A1 and CYP1B1 genes, nor in methylenetetrahydrofolate reductase gene, except that the occurrence of the m2-type of CYP1A1 genetic polymorphism was related to that of the m1-type CYP1A1 polymorphism in the Japanese population. 5. These results suggest that there are race-related differences in the occurrence of genetic polymorphisms in both CYP1A1 and CYP1B1 genes in Japanese and Caucasian populations and that these differences in P450 genetic polymorphisms may, in part, cause differences in the occurrence of lung and breast cancers in these ethnic groups. | ||||||||
| 1220 | 34.12 | 12136243 | 2002.09.12 | + | The 5' end of the KCNQ1OT1 gene is hypomethylated in the Beckwith-Wiedemann syndrome. | Hum Genet | ||
| F Cerrato, M Vernucci, PV Pedone, L Chiariotti, G Sebastio, CB Bruni, A Riccio, | ||||||||
| 1221 | 34.12 | 14586385 | 2003.11.21 | + | + | Cytochrome p450 3A4 messenger ribonucleic acid induction by rifampin in human peripheral blood mononuclear cells: correlation with alprazolam pharmacokinetics. | Clin Pharmacol Ther | |
| I Gashaw, J Kirchheiner, M Goldammer, S Bauer, J Seidemann, K Zoller, PM Mrozikiewicz, I Roots, J Brockmöller, | ||||||||
| OBJECTIVE: There is significant interest in the assessment of the individual cytochrome p450 (CYP) 3A4 activity. We analyzed whether CYP3A4 messenger ribonucleic acid (mRNA) concentrations in leukocytes reflect CYP3A activity in the liver measured by alprazolam as an in vivo probe drug. We also wanted to identify whether genetically determined high CYP3A5 expression is associated with increased alprazolam clearance. METHODS: Alprazolam plasma concentrations were measured 10 hours after intake of 1 mg alprazolam. CYP3A4 mRNA concentrations in peripheral blood mononuclear cells were quantified in 96 healthy volunteers before and after 5-day treatment with 450 mg rifampin (INN, rifampicin) daily. Genetic polymorphisms in CYP2C19, CYP3A4, and CYP3A5 were analyzed by polymerase chain reaction, restriction fragment length polymorphism, and sequencing. RESULTS: The median alprazolam concentration measured 10 hours after dosage was 8.1 mug/L (range, 4.5-14.6 mug/L) before and 1.7 mug/L (range, 0.3-4.1 mug/L) after rifampin treatment. Leukocyte CYP3A4 mRNA was detectable in all samples with a median of 28 molecules per 1 ng total ribonucleic acid before (range, 10-128 molecules per 1 ng total ribonucleic acid) and 50 molecules per 1 ng total ribonucleic acid after (range, 9-484 molecules per 1 ng total ribonucleic acid) rifampin treatment (P <.001). However, mRNA concentrations before and during rifampin induction were largely overlapping, and there was a poor correlation between mRNA concentrations and alprazolam 10-hour trough concentrations reflecting CYP3A4 activity (r = -0.4, P <.001). Alprazolam kinetics did not differ between genetically determined expressers of CYP3A5 (genotype CYP3A5*1/*3) compared with homozygous carriers of the splice site variant. A marginally significant dependence of alprazolam concentrations from the CYP2C19 allele *2 was found (P =.04). CONCLUSIONS: CYP3A4 mRNA concentrations in blood cells were very low and did not reflect systemic drug clearance mediated by CYP3A enzymes. The CYP3A5 genetic polymorphism does not appear relevant for alprazolam kinetics. | ||||||||
| 1222 | 34.11 | 16595709 | 2006.08.31 | + | + | The novel UGT1A9 intronic I399 polymorphism appears as a predictor of 7-ethyl-10-hydroxycamptothecin glucuronidation levels in the liver. | Drug Metab Dispos | |
| H Girard, L Villeneuve, MH Court, LC Fortier, P Caron, Q Hao, LL von Moltke, DJ Greenblatt, C Guillemette, | ||||||||
| Polymorphisms in UGT1A9 were associated with reduced toxicity and increased response to irinotecan in cancer patients. UDP-glucuronosyltransferase (UGT) protein expression, glucuronidation activities for 7-ethyl-10-hydroxycamptothecin (SN-38), and probe substrates of the UGT1A9 and UGT1A1 were measured in 48 human livers to clarify the role of UGT1A9 variants on the in vitro glucuronidation of SN-38. Genotypes were assessed for UGT1A9 (-2152C>T, -275T>A, and -118T(9>10)), three novel UGT1A9 variants (-5366G>T, -4549T>C, and I399C>T), and UGT1A1 (-53TA(6>7), -3156G>A, and -3279T>G). Of all the variants, the UGT1A9 I399C>T was associated with the most dramatic change in SN-38-glucuronide (SN-38G) (2.64-fold; p = 0.0007). Compared with UGT1A9 I399C/C, homozygous I399T/T presented elevated UGT1A1 and UGT1A9 proteins and higher glucuronidation of UGT1A9 and UGT1A1 substrates (p < 0.05). The very low linkage disequilibrium (r(2) < 0.19) between UGT1A9 I399 and all the other UGT1A1 and UGT1A9 variants suggests a direct effect or linkage to unknown functional variant(s) relevant to SN-38 glucuronidation. The UGT1A9 -118T(9/10) was also linked to alteration of SN-38 glucuronidation profiles in the liver (p < 0.05) and was associated with higher UGT1A1 protein (p = 0.03). However, UGT1A9 -118T(10) appears to have low functional impact as a result of the lack of correlation with UGT1A9 protein levels and a modest 1.4-fold higher reporter gene expression associated with the -118T(10) allele in HepG2 cells (p = 0.004). In contrast, the UGT1A9 -5366T, -4549C, -2152T, and -275A, associated with higher UGT1A9 protein (2-fold; p < 0.05), have no influence on SN-38G. Despite limitations resulting from sample size, results indicate that UGT1A9 I399 and -118T(9/10) may represent additional candidates in combination with UGT1A1 promoter haplotypes for the prediction of SN-38 glucuronidation profile in vivo. | ||||||||
| 1223 | 34.11 | 11038154 | 2000.11.20 | + | + | Cytochrome P4502C9 is the principal catalyst of racemic acenocoumarol hydroxylation reactions in human liver microsomes. | Drug Metab Dispos | |
| HH Thijssen, JP Flinois, PH Beaune, | ||||||||
| The oral anticoagulant acenocoumarol is given as a racemic mixture. The (S)-enantiomer is rapidly cleared and is the reason why only (R)-acenocoumarol contributes to the pharmacological effect. The objective of the study was to establish the cytochrome P450 (CYP) enzymes catalyzing the hydroxylations of the acenocoumarol enantiomers. Of various cDNA-expressed human CYPs, only CYP2C9 hydroxylated (S)-acenocoumarol. Hydroxylation occurred at the 6-, 7-, and 8-position with equal K(m) values and a ratio of 0.9:1:0.1 for V(max). CYP2C9 also mediated the 6-, 7-, and 8-hydroxylations of (R)-acenocoumarol with K(m) values three to four times and V(max) values one-sixth times those of (S)-acenocoumarol. (R)-Acenocoumarol was also metabolized by CYP1A2 (6-hydroxylation) and CYP2C19 (6-, 7-, and 8-hydroxylation). In human liver microsomes one enzyme only catalyzed (S)-acenocoumarol hydroxylations with K(m) values < 1 microM. In most of the samples tested the 7-hydroxylation of (R)-acenocoumarol was also catalyzed by one enzyme only. The 6-hydroxylation was catalyzed by at least two enzymes. Sulfaphenazole could completely inhibit in a competitive way the hydroxylations of (S)-acenocoumarol and the 7-hydroxylation of (R)-acenocoumarol. The 6-hydroxylation of (R)-acenocoumarol could be partially inhibited by sulfaphenazole, 40 to 50%, and by furafylline, 20 to 30%. Significant mutual correlations were obtained between the hydroxylations of (S)-acenocoumarol, the 7-hydroxylation of (R)-acenocoumarol, the 7-hydroxylation of (S)-warfarin, and the methylhydroxylation of tolbutamide. The results demonstrate that (S)-acenocoumarol is hydroxylated by a single enzyme, namely CYP2C9. CYP2C9 is also the main enzyme in the 7-hydroxylation of (R)-acenocoumarol. Other enzymes involved in (R)-acenocoumarol hydroxylation reactions are CYP1A2 and CYP2C19. Drug interactions must be expected, particularly for drugs interfering with CYP2C9. Also, drugs interfering with CYP1A2 and CYP2C19 may potentiate acenocoumarol anticoagulant therapy. | ||||||||
| 1224 | 34.10 | 12960506 | 2004.04.01 | + | + | Transcriptional activity of the tandem repeat polymorphism in the 5'-flanking region of the human CYP2E1 gene. | Alcohol Clin Exp Res | |
| F Nomura, S Itoga, T Uchimoto, T Tomonaga, M Nezu, H Shimada, T Ochiai, | ||||||||
| BACKGROUND: There are remarkable interindividual differences in the expression of cytochrome P-4502E1(CYP2E1), which in turn may alter susceptibility to alcohol-related diseases and various cancers. We recently characterized the tandem repeat polymorphism in the 5'-flanking region of the human CYP2E1 gene and found that subjects with the homozygous mutant-type (A4/A4) may be at higher risk of developing esophageal cancer. In this study, we determined how this tandem repeat polymorphism alters transcriptional activities of the human CYP2E1 gene by transfection studies. METHODS: The 5'-flanking region (-2,562 base pair to +9 base pair) of the CYP2E1 gene from three individuals of different genotypes (A2/A2, A2/A4, A4/A4) was amplified by polymerase chain reaction. The polymerase chain reaction products placed in front of a luciferase reporter gene were transfected into human hepatoblastoma cells, human esophageal cancer cells, and human uterus cancer cells. Transcriptional activities were determined by the dual-luciferase assay. When indicated, ethanol (50 mM) was included in the culture medium. CYP2E1 messenger RNA levels in peripheral lymphocytes were measured by the real-time reverse transcription-polymerase chain reaction using the LightCycler system. RESULTS: The construct including the tandem repeat region exhibited luciferase activities in both A2 and A4 type. It was of note that the activity produced by the A4 allele was significantly greater than that by A2 allele in HeLa cells (p < 0.001). CYP2E1 messenger RNA levels in peripheral blood lymphocytes were comparable between the two genotypes. CONCLUSION: Transcriptional activity of the mutant allele of the tandem repeat polymorphism in the 5'-flanking region of the CYP2E1 gene is greater than that of the wild type. | ||||||||
| 1225 | 34.10 | 15459969 | 2005.07.29 | + | + | Spectrum of PTCH mutations in Italian nevoid basal cell-carcinoma syndrome patients: identification of thirteen novel alleles. | Hum Mutat | |
| M Savino, M d'Apolito, V Formica, F Baorda, F Mari, A Renieri, E Carabba, E Tarantino, E Andreucci, S Belli, L Lo Muzio, B Dallapiccola, L Zelante, A Savoia, | ||||||||
| The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant genetic disease characterized by numerous basal cell carcinomas, odontogenic keratocysts of the jaws, palmar and plantal pits, skeletal abnormalities, and calcification of the falx cerebri. The gene responsible for this syndrome is the PTCH tumor suppressor gene encoding for the sonic hedgehog receptor. In this paper, we report thirteen novel mutations identified in the first screening of NBCCS patients in Italy. Except for p.T230P and p.F505_L506delinsLR, all the other mutations are predicted to determine a premature truncation of the protein. | ||||||||
| 1226 | 34.09 | 10921887 | 2000.09.28 | + | + | A repressor sequence in the juxtamembrane domain of Flt-1 (VEGFR-1) constitutively inhibits vascular endothelial growth factor-dependent phosphatidylinositol 3'-kinase activation and endothelial cell migration. | EMBO J | |
| H Gille, J Kowalski, L Yu, H Chen, MT Pisabarro, T Davis-Smyth, N Ferrara, | ||||||||
| Vascular endothelial growth factor (VEGF) has two highly homologous tyrosine kinase receptors: Flt-1 (VEGFR-1) and KDR (VEGFR-2). KDR is strongly phosphorylated on tyrosines and can transmit mitogenic and motogenic signals following VEGF binding, while Flt-1 is markedly less effective in mediating such functions. To dissect the regions that account for the differences between the two receptors, we generated a series of chimeric Flt-1-KDR molecules. We found that the juxtamembrane region of Flt-1 prevents key signaling functions. When the juxtamembrane region of Flt-1 is replaced by that of KDR, Flt-1 becomes competent to mediate endothelial cell migration and phosphatidylinositol 3'-kinase activation in response to VEGF. Further mutational analysis shows that a short divergent sequence is responsible for such repressor function. However, mutant Flt-1 receptors lacking this sequence do not transmit effective proliferative signals, suggesting that this receptor function is regulated separately. These results define a novel functional domain that serves to repress Flt-1 activity in endothelial cells. | ||||||||
| 1227 | 34.09 | 11394901 | 2001.07.12 | + | + | Identification of a single nucleotide polymorphism in the TATA box of the CYP2A6 gene: impairment of its promoter activity. | Biochem Biophys Res Commun | |
| M Pitarque, O von Richter, B Oke, H Berkkan, M Oscarson, M Ingelman-Sundberg, | ||||||||
| Human cytochrome P450 2A6 (CYP2A6) constitutes the major nicotine oxidase, and large interindividual differences are seen in the levels of this enzyme, to a great extent caused by the distribution of several different polymorphic gene variants mainly located in the open reading frame (ORF). In the present study, we report a common polymorphism located in the 5' flanking region of CYP2A6 affecting its expression. DHPLC analysis and complete sequence of the open reading frame of the gene from a Turkish individual revealed a -48T > G substitution disrupting the TATA box. Using dynamic allele-specific hybridization (DASH), genotyping of this novel variant (named CYP2A6*9) was carried out in 116 Swedish, 132 Turkish, and 102 Chinese subjects, and the allele frequencies were found to be 5.2, 7.2, and 15.7%, respectively. The significance of the polymorphism was investigated by the construction of luciferase reporter plasmids containing 135 or 500 bp of the 5'-upstream region of the gene transfected into human hepatoma B16A2 cells. The constructs carrying the -48T > G mutation were only expressed at about 50% of the wild-type alleles. It is concluded that the CYP2A6*9 allele might be one of the most common CYP2A6 variants in Caucasians that alters the levels of enzyme expression. | ||||||||
| 1228 | 34.09 | 17085484 | 2007.04.02 | + | + | Haplotype spanning TTC12 and ANKK1, flanked by the DRD2 and NCAM1 loci, is strongly associated to nicotine dependence in two distinct American populations. | Hum Mol Genet | |
| J Gelernter, Y Yu, R Weiss, K Brady, C Panhuysen, BZ Yang, HR Kranzler, L Farrer, | ||||||||
| Nicotine dependence (ND) is a moderately heritable trait. We ascertained a set of 1615 subjects in 632 families [319 African-American (AA) and 313 European-American (EA)] based on affected sibling pairs with cocaine or opioid dependence. Subjects were interviewed with the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). Previously, we identified a modest linkage peak (LOD score =1.97) for ND in the EA part of the sample on chromosome 11q23, a region that includes the NCAM1-TTC12-ANKK1-DRD2 gene cluster. DRD2 and NCAM1 are functional candidate genes for substance dependence; the TTC12 and ANKK1 loci are not well characterized. We genotyped a set of 43 single nucleotide polymorphisms (SNPs) spanning this region, and performed family-based association and haplotype analysis. There was relatively weak evidence for association of the flanking DRD2 and NCAM1 markers to ND, but very strong evidence of association of multiple SNPs at TTC12 and ANKK1 in both populations (minimal P=0.0007 in AAs and minimal P=0.00009 in EAs), and in the pooled sample, as well as strong evidence for highly significant association of a single haplotype spanning TTC12 and ANKK1 to ND in the pooled sample (P=0.0000001). We conclude that a risk locus for ND, important both in AAs and EAs, maps to a region that spans TTC12 and ANKK1. Functional studies of these loci are warranted. These results provide additional information useful in evaluating the many earlier discrepant findings regarding association of DRD2 with substance dependence. | ||||||||
| 1229 | 34.09 | 11679585 | 2002.01.24 | + | + | Transcriptional regulation of CYP2C9 gene. Role of glucocorticoid receptor and constitutive androstane receptor. | J Biol Chem | |
| S Gerbal-Chaloin, M Daujat, JM Pascussi, L Pichard-Garcia, MJ Vilarem, P Maurel, | ||||||||
| Although cytochrome P450 2C9 (CYP2C9) is a major CYP expressed in the adult human liver, its mechanism of regulation is poorly known. In previous work, we have shown that CYP2C9 is inducible in primary human hepatocytes by xenobiotics including dexamethasone, rifampicin, and phenobarbital. The aim of this work was to investigate the molecular mechanism(s) controlling the inducible expression of CYP2C9. Deletional analysis of CYP2C9 regulatory region (+21 to -2088) in the presence of various hormone nuclear receptors suggested the presence of two functional response elements, a glucocorticoid receptor-responsive element (-1648/-1684) and a constitutive androstane receptor-responsive element (CAR, -1783/-1856). Each of these were characterized by co-transfection | ||||||||