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Novel single nucleotide polymorphism in CYP2C9 is associated with changes in warfarin clearance and CYP2C9 expression levels in African Americans.

ABSTRACT: Warfarin is a widely used anticoagulant whose active S-enantiomer is primarily metabolized by the CYP2C9 enzyme. The CYP2C9*2 and CYP2C9*3 alleles are associated with lower warfarin dose requirement and decreased enzyme activity. In contrast, we previously identified a novel single-nucleotide polymorphism (SNP) (rs7089580A > T) in CYP2C9 that is associated with higher warfarin dose requirement in African Americans (AAs). In this study, we examine the effect of rs7089580 on warfarin pharmacokinetics and CYP2C9 expression in 63 AA patients and 32 AA liver tissues, respectively. We found oral clearance of S-warfarin to be higher among carriers of the minor rs7089580 allele (T) compared with wild-type homozygotes (3.73 ± 1.46 vs 2.95 ± 1.39 mL/min; P = 0.04). CYP2C9 messenger RNA expression in liver tissue was also higher among A/T and T/T genotypes compared with A/A (P < 0.02). Our findings indicate that rs7089580 is associated with higher S-warfarin clearance and CYP2C9 expression and may help explain the higher dose requirement of warfarin in AAs. Furthermore, rs7089580 is in complete linkage disequilibrium with the promoter SNP rs12251841 in AAs, which may provide a biologically plausible explanation for the observed effect on CYP2C9 expression levels. Given the many clinically relevant substrates of CYP2C9, identifying polymorphisms that affect expression levels and metabolism across ethnicities is essential for individualization of doses with a narrow therapeutic index.

SUBMITTER: Hernandez W

PROVIDER: S-EPMC4433569 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

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Novel single nucleotide polymorphism in CYP2C9 is associated with changes in warfarin clearance and CYP2C9 expression levels in African Americans.

Hernandez Wenndy W Aquino-Michaels Keston K Drozda Katarzyna K Patel Shitalban S Jeong Young Y Takahashi Harumi H Cavallari Larisa H LH Perera Minoli A MA

Translational research : the journal of laboratory and clinical medicine 20141122 6

Warfarin is a widely used anticoagulant whose active S-enantiomer is primarily metabolized by the CYP2C9 enzyme. The CYP2C9*2 and CYP2C9*3 alleles are associated with lower warfarin dose requirement and decreased enzyme activity. In contrast, we previously identified a novel single-nucleotide polymorphism (SNP) (rs7089580A > T) in CYP2C9 that is associated with higher warfarin dose requirement in African Americans (AAs). In this study, we examine the effect of rs7089580 on warfarin pharmacokinet ...[more]

PMID: 25499099

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Project description:BACKGROUND: Cytochrome P4502C9 (CYP2C9) plays a vital role in drug metabolism. There has been an increased effort to identify polymorphisms within the gene and determine their clinical consequences. However, most of these efforts have focused on populations of European descent. Herein we report the influence of CYP2C9 genotype on warfarin dose among European American and African American patients. We also identify two new mutations; one in the coding region and one in the non-coding region of the CYP2C9 gene. METHODS: Patients (?20 years of age) are enrolled after obtaining medical, lifestyle and concomitant medication history. Changes in International Normalized Ratio (INR), warfarin dose, co-medications, diet, physical activity and the occurrence of complications are documented. CYP2C9 genotype was determined using PCR-RFLP and pyrosequencing. Differences in genotype frequencies and HWE assumptions were assessed using ?(2) statistics and exact tests. The genotype dose association was evaluated using multivariable linear regression. RESULTS: This report includes 490 patients (mean age 60.6 ± 15.6, 51.3% men). African American patients comprise 48.9% of the cohort with mean follow-up of 13.5 (±10.6) months. Both the CYP2C9 *2 and *3 allele were more frequent in European Americans (11.24%, 5.1%) compared to African Americans (1.1% and 1.8%). CYP2C9 *5 (0.9%), *6 (0.4%), and *11 (1.1%) variants were only observed in African Americans. The variant genotype is more frequent among European Americans compared to African Americans (29.8% vs. 9.73%, p<0.0001). Warfarin dose was significantly related to CYP2C9 genotype (p<0.0001) both in univariate and multivariate analyses. Multivariable race-specific analyses highlight the contribution of CYP2C9 genotype among European American but not among African American patients. CONCLUSION: The variant CYP2C9 genotype is more frequent among European Americans compared to African Americans. Among African Americans the variant genotype frequency is higher than previously reported. CYP2C9 genotype predicts warfarin dose in European Americans, but not in African Americans.

Project description:IntroductionAfrican Americans have a higher incidence of venous thromboembolism (VTE) than European descent individuals. However, the typical genetic risk factors in populations of European descent are nearly absent in African Americans, and population-specific genetic factors influencing the higher VTE rate are not well characterized.MethodsWe performed a candidate gene analysis on an exome-sequenced African American family with recurrent VTE and identified a variant in Protein S (PROS1) V510M (rs138925964). We assessed the population impact of PROS1 V510M using a multicenter African American cohort of 306 cases with VTE compared to 370 controls. Additionally, we compared our case cohort to a background population cohort of 2203 African Americans in the NHLBI GO Exome Sequencing Project (ESP).ResultsIn the African American family with recurrent VTE, we found prior laboratories for our cases indicating low free Protein S levels, providing functional support for PROS1 V510M as the causative mutation. Additionally, this variant was significantly enriched in the VTE cases of our multicenter case-control study (Fisher's Exact Test, P = 0.0041, OR = 4.62, 95% CI: 1.51-15.20; allele frequencies - cases: 2.45%, controls: 0.54%). Similarly, PROS1 V510M was also enriched in our VTE case cohort compared to African Americans in the ESP cohort (Fisher's Exact Test, P = 0.010, OR = 2.28, 95% CI: 1.26-4.10).ConclusionsWe found a variant, PROS1 V510M, in an African American family with VTE and clinical laboratory abnormalities in Protein S. Additionally, we found that this variant conferred increased risk of VTE in a case-control study of African Americans. In the ESP cohort, the variant is nearly absent in ESP European descent subjects (n = 3, allele frequency: 0.03%). Additionally, in 1000 Genomes Phase 3 data, the variant only appears in African descent populations. Thus, PROS1 V510M is a population-specific genetic risk factor for VTE in African Americans.

Project description:Objective: To explore the effect of PITX2 gene rs6843082 single nucleotide polymorphism on the efficacy and adverse reactions of warfarin in patients with atrial fibrillation and hypertension, and to provide a theoretical basis for individualized warfarin treatment.Methods: Data on 97 patients with atrial fibrillation and hypertension treated in our hospital were collected from September, 2018 to December, 2019. PCR and SNP genotyping techniques were used to measure the genotype at the rs6843082 locus (pituitary homeobox 2, PITX2) using DNA from the peripheral blood cells of all patients. We compared the efficacy of warfarin and the incidence of adverse reactions in patients of different genotypes.Results: (1) Among 97 subjects, 58 cases (59.79%), 32 cases (32.99%) and 7 cases (7.22%) of PITX2 (rs6843082) genotypes GG, GA and AA were identified respectively. The G and A allele frequencies were 76.29% and 23.71%, respectively. (2) After all patients took warfarin to achieve the standard, the GA group and AA group's time to achieve the standard was significantly longer than that of the GG group (P<0.05). The difference was not statistically significant among groups (P>0.05). Compared with the GG group, the maintenance dose of the AA group was increased (P<0.05). (3) Compared with the GG and the GA group, the probability of bleeding events was higher in the AA group (P<0.05). (4) There was no difference in left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV) group among GG, GA and AA groups (P>0.05). Compared with the GG group, left ventricular ejection fraction (LVEF) of the AA group was significantly reduced (P<0.05). (5) The mortality rates of the GG, GA, and AA groups were 15.51%, 12.50% and 22.57%, respectively, at the end of 120 d follow-up.Conclusion: Our findings show that rs6843082 SNP leads to the warfarin dose response differences that were observed in patients with atrial fibrillation and hypertension. Genotyping patients for rs6843082 before initiating warfarin treatment may optimize the treatment response and reduce bleeding incidence.

Dataset Information

Novel single nucleotide polymorphism in CYP2C9 is associated with changes in warfarin clearance and CYP2C9 expression levels in African Americans.

Publications

Novel single nucleotide polymorphism in CYP2C9 is associated with changes in warfarin clearance and CYP2C9 expression levels in African Americans.

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