Impact of VKORC1, CYP4F2 and NQO1 gene variants on warfarin dose requirement in Han Chinese patients with catheter ablation for atrial fibrillation.
ABSTRACT: BACKGROUND:The anticoagulation of atrial fibrillation catheter ablation during the perioperative stage does matter and should be treated with discretion. We aimed to assess impact of three important genes participating in vitamin K cycle (i.e. VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566) on the daily stable warfarin dose requirement in Sichuan Han Chinese patients with catheter ablation of atrial fibrillation. METHODS:A total of 222 atrial fibrillation patients taking stable warfarin therapy after catheter ablation operation were enrolled in this study. The study population included had high (?2) risk according to the CHA2DS2-VASc risk score. Genotypes of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 were analyzed by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Multiple linear regression analysis was applied to depict the impact of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 on the daily stable warfarin dose requirement. RESULTS:Carriers of VKORC1 rs9923231 AG/GG genotypes required significantly higher warfarin dose (3.03?±?0.28 mg/day, 7.19 mg/day, respectively) than AA carriers (2.52?±?0.07 mg/day; P
Project description:CYP2C9 and VKORC1 are two major genetic factors associated with inter-individual variability in warfarin dose. Additionally, genes in the warfarin metabolism pathway have also been associated with dose variance. We analyzed Single Nucleotide Polymorphisms (SNPs) in these genes to identify genetic factors that might confer warfarin sensitivity in Indonesian patients.Direct sequencing method was used to identify SNPs in CYP2C9, VKORC1, CYP4F2, EPHX1, PROC and GGCX genes in warfarin-treated patients. Multiple linear regressions were performed to model the relationship warfarin daily dose requirement with genetic and non-genetic variables measured and used to develop a novel algorithm for warfarin dosing.From the 40 SNPs analyzed, CYP2C9 rs17847036 and VKORC1 rs9923231 showed significant association with warfarin sensitivity. In our study population, no significant correlation could be detected between CYP2C9*3, CYP2C9C-65 (rs9332127), CYP4F2 rs2108622, GGCX rs12714145, EPHX1 rs4653436 and PROC rs1799809 with warfarin sensitivity.VKORC1 rs9923231 AA and CYP2C9 rs17847036 GG genotypes were associated with low dosage requirements of most patients (2.05 ± 0.77 mg/day and 2.09 ± 0.70 mg/day, respectively). CYP2C9 and VKORC1 genetic variants as well as non-genetic factors such as age, body weight and body height account for 15.4% of variance in warfarin dose among our study population. Additional analysis of this combination could allow for personalized warfarin treatment in ethnic Indonesians.
Project description:AIM:To determine whether VKORC1 rs9923231, CYP2C9 rs1057910, CYP4F2 rs2108622 and ORM1 rs17650 genotypes contribute to warfarin therapy in patients during initiation and maintenance anticoagulation treatment after heart valve surgery. METHODS:287 Chinese patients with warfarin treatment more than three month after heart valve replacement operations were enrolled. Blood was collected from each subject for DNA extraction and genotyping. Analyzing the relationship between genotypes and warfarin curative effect. RESULTS:Their mean age was 48.0 ± 10.5 years old. During the initiation phase, the growth rate of INR was partial correlated with VKORC1 rs9923231, CYP2C9 rs1057910 and ORM1 rs17650, respectively. Compared with AG or GG genotypes of VKORC1 c.-1639 carriers, patients with VKORC1 c.-1639AA reached target INR therapeutic range faster (P<0.001) and has a high risk of overanticoagulation (P<0.001). Carriers of at least one CYP2C9 *3 allele reached the target INR therapeutic range and supra-therapeutic INR were faster than CYP2C9 wild-type carriers (P=0.032, P=0.032, respectively). CYP4F2 rs2108622 could significantly influence on time to the target INR therapeutic range and time to INR above 3.0 after hierarchical analysis with VKORC1, CYP2C9 and ORM1 (P=0.011, P=0.044, respectively). VKORC1 rs9923231, CYP2C9 rs1057910 and ORM1 rs17650 were significantly influence the %TTR in three months (P=0.031, P=0.008, P=0.001, respectively). During the maintenance phase, VKORC1 c.-1639AA carriers spent more time at supra-therapeutic INRs (P<0.001). CYP2C9 rs1057910, CYP4F2 rs2108622 and ORM1 rs17650 gene variants did not affect outcome parameters in maintenance phase. CONCLUSIONS:This study found that genetic factors could significantly affected on warfarin therapy in Chinese. Meanwhile, genetic variations play a more important role in the initial phase than did in maintenance phase of warfarin therapy.
Project description:WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Genetic polymorphisms of VKORC1 and CYP2C9 are known to influence warfarin dosage. * Recent studies among Caucasians showed that polymorphisms of CYP4F2 also play a role in warfarin pharmacogenetics. * The contribution of CYP4F2 variants to the variability inwarfarin dose requirement in Chinese subjects remains to be investigated. WHAT THIS STUDY ADDS * This research was to study the effect of CYP4F2 variants on warfarin requirements in the Han Chinese population. * This study developed a multiple regression model including CYP2C9, VKORC1 3673G>A, CYP4F2 genotypes and age, weight, combination use of amiodarone which could explain 56.1% of the individual variability in warfarin dose CYP4F2 could explain 4% of the variance in warfarin dose. * We found that one novel genotypic polymorphism 5417G>T for Asp36Tyr, which was identified as an important marker of warfarin resistance, was absent in the Han Chinese population in our study. AIMS The objective of this study was to assess the effect of the CYP4F2 on the daily stable warfarin dose requirement in Han Chinese patients with mechanical heart valve replacement (MHVR). METHODS From March 2007 to November 2008, 222 Han Chinese MHVR patients were recruited in our study. VKORC1 3673G>A, 5417G>T, CYP2C9*3 and CYP4F2 rs2108622 were genotyped by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Polymorphisms of VKORC1 9041G>A were detected by direct sequencing. Multiple linear regression analysis was used to investigate the contribution of CYP4F2. RESULTS The CYP4F2 rs2108622 CT/TT group took a significantly higher stable warfarin dose (3.2 mg day(-1)) than the CC group (2.9 mg day(-1), 95% CI 0.2, 1.0, P= 0.033). The multiple linear regression model included VKORC1 3673G>A, CYP2C9, CYP4F2 genotypes and clinical characteristics. The model could explain 56.1% of the variance in stable warfarin dose in Han Chinese patients with MHVR. CYP4F2 contributed about 4% to the variance in the warfarin dose. There was no variation in the SNPs of VKORC1 5417G>T. CONCLUSION CYP4F2 is a minor significant factor of individual variability in the stable warfarin dose in Han Chinese patients with MHVR. The effect of CYP2C9 and VKORC1 genotypes on variability in the stable warfarin dose had also been confirmed.
Project description:The effects of genetic variants on warfarin dosing vary among different ethnic groups, especially in the Chinese population. The objective of this study was to recruit patients through a rigorous experimental design and to perform a comprehensive screen to identify gene polymorphisms that may influence warfarin dosing in northern Han Chinese patients with mechanical heart valve replacement. Consenting patients (n?=?183) with a stable warfarin dose were included in this study. Ninety-six single nucleotide polymorphisms (SNPs) in 30 genes involved in warfarin pharmacological pathways were genotyped using the Illumina SNP GoldenGate Assay, and their associations with warfarin dosing were assessed using univariate regression analysis with post hoc comparison using least significant difference analysis. Multiple linear regression was performed by incorporating patients' clinical and genetic data to create a new algorithm for warfarin dosing. From the 96 SNPs analyzed, VKORC1 rs9923231, CYP1A2 rs2069514, CYP3A4 rs28371759, and APOE rs7412 were associated with higher average warfarin maintenance doses, whereas CYP2C9 rs1057910, EPHX1 rs2260863, and CYP4F2 rs2189784 were associated with lower warfarin doses (P?<?0.05). Multiple linear regression analysis could estimate 44.4% of warfarin dose variability consisting of, in decreasing order, VKORC1 rs9923231 (14.2%), CYP2C9*3 (9.6%), body surface area (6.7%), CYP1A2 rs2069514 (3.7%), age (2.7%), CYP3A4 rs28371759 (2.5%), CYP4F2 rs2108622 (1.9%), APOE rs7412 (1.7%), and VKORC1 rs2884737 (1.4%). In the dosing algorithm we developed, we confirmed the strongest effects of VKORC1, CYP2C9 on warfarin dosing. In the limited sample set, we also found that novel genetic predictors (CYP1A2, CYP3A4, APOE, EPHX1, CYP4F2, and VKORC1 rs2884737) may be associated with warfarin dosing. Further validation is needed to assess our results in larger independent northern Chinese samples.
Project description:Genetic polymorphisms in the gene encoding cytochrome P450 (CYP) 4F2, a vitamin K oxidase, affect stable warfarin dose requirements and time to therapeutic INR. CYP4F2 is part of the CYP4F gene cluster, which is highly polymorphic and exhibits a high degree of linkage disequilibrium, making it difficult to define causal variants. Our objective was to examine the effect of genetic variability in the CYP4F gene cluster on expression of the individual CYP4F genes and warfarin response. mRNA levels of the CYP4F gene cluster were quantified in human liver samples (n = 149) obtained from a well-characterized liver bank and fine mapping of the CYP4F gene cluster encompassing CYP4F2, CYP4F11, and CYP4F12 was performed. Genome-wide association study (GWAS) data from a prospective cohort of warfarin-treated patients (n = 711) was also analyzed for genetic variations across the CYP4F gene cluster. In addition, SNP-gene expression in human liver tissues and interactions between CYP4F genes were explored in silico using publicly available data repositories. We found that SNPs in CYP4F2, CYP4F11, and CYP4F12 were associated with mRNA expression in the CYP4F gene cluster. In particular, CYP4F2 rs2108622 was associated with increased CYP4F2 expression while CYP4F11 rs1060467 was associated with decreased CYP4F2 expression. Interestingly, these CYP4F2 and CYP4F11 SNPs showed similar effects with warfarin stable dose where CYP4F11 rs1060467 was associated with a reduction in daily warfarin dose requirement (?1 mg/day, Pc = 0.017), an effect opposite to that previously reported with CYP4F2 (rs2108622). However, inclusion of either or both of these SNPs in a pharmacogenetic algorithm consisting of age, body mass index (BMI), gender, baseline clotting factor II level, CYP2C9?2 rs1799853, CYP2C9?3 rs1057910, and VKORC1 rs9923231 improved warfarin dose variability only by 0.5-0.7% with an improvement in dose prediction accuracy of ?1-2%. Although there is complex regulation across the CYP4F gene cluster, the opposing effects between the two SNPs in the CYP4F gene cluster appear to compensate for each other and their effect on warfarin dose requirement is unlikely to be clinically significant.
Project description:<h4>Objectives</h4>As the most frequently prescribed anticoagulant, warfarin has large inter-individual variability in dosage. Genetic polymorphisms could largely explain the differences in dosage requirement. rs9923231 (VKORC1), rs7294 (VKORC1), rs1057910 (CYP2C9), rs2108622 (CYP4F2), and rs699664 (GGCX) involved in the warfarin action mechanism and the circulatory vitamin K were selected to investigate their polymorphism characteristics and their effects on the pharmacodynamics and pharmacokinetics of warfarin in Chinese population.<h4>Methods</h4>220 patients with cardiac valve replacement were recruited. International normalized ratio and plasma warfarin concentrations were determined. The five genetic polymorphisms were genotyping by pyro-sequencing. The relationships of maintenance dose, plasma warfarin concentration and INR were assessed among groups categorized by genotypes.<h4>Results</h4>rs9923231 and rs7294 in VKORC1 had the analogous genotype frequencies (D': 0.969). 158 of 220 recruited individuals had the target INR (1.5-2.5). Patients with AA of rs9923231 and CC of rs7294 required a significantly lower maintenance dose and plasma concentration than those with AG and TC, respectively. The mean weekly maintenance dose was also significantly lower in CYP2C9 rs1057910 mutated heterozygote than in patients with the wild homozygote. Eliminating the influence from environment factors (age, body weight and gender), rs9923231 and rs1057910 could explain about 32.0% of the variability in warfarin maintenance dose; rs7294 could explain 26.7% of the variability in plasma concentration. For patients with allele G of rs9923231 and allele T of rs7294, higher plasma concentration was needed to achieve the similar goal INR.<h4>Conclusions</h4>A better understanding of the genetic variants in individuals can be the foundation of warfarin dosing algorithm and facilitate the reasonable and effective use of warfarin in Chinese.
Project description:The aim of this study was to investigate the contributions of non-genetic and genetic factors on the variability of stable warfarin doses in Thai patients.A total of 250 Thai patients with stable warfarin doses were enrolled in the study. Demographics and clinical data, e.g., age, body mass index, indications for warfarin and concomitant medications, were documented. Four single nucleotide polymorphisms in the VKORC1 - 1639G > A, CYP2C9*3, CYP4F2 rs2108622, and UGT1A1 rs887829 genes were detected from gDNA using TaqMan allelic discrimination assays.The patients with variant genotypes of VKORC1 - 1639G > A required significantly lower warfarin stable weekly doses (SWDs) than those with wild-type genotype (p < 0.001). Similarly, the patients with CYP2C9*3 variant allele required significantly lower warfarin SWDs than those with homozygous wild-type (p = 0.006). In contrast, there were no significant differences in the SWDs between the patients who carried variant alleles of CYP4F2 rs2108622 and UGT1A1 rs887829 as compared to wild-type allele carriers. Multivariate analysis, however, showed that CYP4F2 rs2108622 TT genotype accounted for a modest part of warfarin dose variability (1.2%). In contrast, VKORC1 - 1639G > A, CYP2C9*3, CYP4F2 rs2108622 genotypes and non-genetic factors accounted for 51.3% of dose variability.VKORC1 - 1639G > A, CYP2C9*3, and CYP4F2 rs2108622 polymorphisms together with age, body mass index, antiplatelet drug use, amiodarone use, and current smoker status explained 51.3% of individual variability in stable warfarin doses. In contrast, the UGT1A1 rs887829 polymorphism did not contribute to dose variability.
Project description:The aim of this study was to investigate whether the VKORC1*3 (rs7294/9041 G?>?A), VKORC1*4 (rs17708472/6009 C?>?T), and CYP4F2 (rs2108622/1347 C?>?T) polymorphisms were associated with elevated warfarin maintenance dose requirements in patients with myocardial infarction (n = 105) from the Warfarin Aspirin Reinfarction Study (WARIS-II). We found significant associations between elevated warfarin dose requirements and VKORC1*3 and VKORC1*4 polymorphisms (P = .001 and P = .004, resp.), whereas CYP4F2 (1347 C?>?T) showed a weak association on higher warfarin dose requirements (P = .09). However, analysing these variant alleles in a regression analysis together with our previously reported data on VKORC1*2, CYP2C9*2 and CYP2C9*3 polymorphisms, gave no significant associations for neither VKORC1*3, VKORC1*4 nor CYP4F2 (1347 C?>?T). In conclusion, in patients with myocardial infarction, the individual contribution to warfarin dose requirements from VKORC1*3, VKORC1*4, and CYP4F2 (1347 C?>?T) polymorphisms was negligible. Our results indicate that pharmacogenetic testing for VKORC1*2, CYP2C9*2 and CYP2C9*3 is more informative regarding warfarin dose requirements than testing for VKORC1*3, VKORC1*4, and CYP4F2 (1347 C?>?T) polymorphisms.
Project description:Differences in warfarin maintenance dosages based on the presence of polymorphisms in VKORC1, CYP2C9, CYP4F2, and ORM1 can be determined through dosage adjustment according to routine guidelines. Little is known about whether routine therapy could provide consensus anticoagulation control for patients with different genotypes. This study was carried out to compare anticoagulant control in patients with different genotypes. Six hundred seventy patients using warfarin according to Chinese guidelines were enrolled. Warfarin dosages and monitored international normalized ratios (INRs) were recorded. Genotypes of VKORC1 rs9923231, CYP4F2 rs2108622, CYP2C9 rs1057910, and ORM1 rs17650 polymorphisms were determined. Warfarin dosages and INR were compared between genotypes. Patients with the AGCC*F*F*1*1 polymorphism took longer than patients with the AACC*F*F*1*1 polymorphism (20 vs 5 days, P < .001) to achieve the targeted INR range. The INR values of patients with AACC*F*F*1*3 were unstable and did not enter the stable state control phase until after 35 days. The peak INR of patients with the AACC*F*F*1*3 polymorphism was exceedingly high, with some values exceeding the control range limit of 3.0. Patients with the AACC*F*S*1*1 or AACT*F*F*1*1 polymorphisms exhibited similar INR values as the patients with the AACC*F*F*1*1 polymorphism. This study found that routine medication with warfarin provides significantly different levels of anticoagulant control between patients with wild-type genotypes and patients with heterozygous polymorphism genotypes of VKORC1 rs9923231 or CYP2C9 rs1057910. Patients with heterozygous polymorphism genotypes of VKORC1 or CYP2C9 require genotype-directed therapy with warfarin to increase efficacy and safety in anticoagulant treatment.
Project description:AIM:The objective of this study was to determine the additional contribution of NQO1 and CYP4F2 genotypes to warfarin dose requirements across two racial groups after accounting for known clinical and genetic predictors. PATIENTS & METHODS:The following were assessed in a cohort of 260 African-Americans and 53 Hispanic-Americans: clinical data; NQO1 p.P187S (*1/*2); CYP2C9*2, *3, *5, *6, *8 and *11; CYP4F2 p.V433M; and VKORC1 c.-1639G>A genotypes. RESULTS:Both the CYP4F2 433M (0.23 vs 0.06; p < 0.05) and NQO1*2 (0.27 vs 0.18; p < 0.05) allele frequencies were higher in Hispanic-Americans compared with African-Americans. Multiple regression analysis in the Hispanic-American cohort revealed that each CYP4F2 433M allele was associated with a 22% increase in warfarin maintenance dose (p = 0.019). Possession of the NQO1*2 allele was associated with a 34% increase in warfarin maintenance dose (p = 0.004), while adjusting for associated genetic (CYP2C9, CYP4F2 and VKORC1) and clinical factors. In this population, the inclusion of CYP4F2 and NQO1*2 genotypes improved the dose variability explained by the model from 0.58 to 0.68 (p = 0.001), a 17% relative improvement. By contrast, there was no association between CYP4F2 or NQO1*2 genotype and therapeutic warfarin dose in African-Americans after adjusting for known genetic and clinical predictors. CONCLUSION:In our cohort of inner-city Hispanic-Americans, the CYP4F2 and NQO1*2 genotypes significantly contributed to warfarin dose requirements. If our findings are confirmed, they would suggest that inclusion of the CYP4F2 and NQO1*2 genotypes in warfarin dose prediction algorithms may improve the predictive ability of such algorithms in Hispanic-Americans.