Linkage disequilibrium between the CYP2C19*2,*17 and CYP2C9*1 alleles and impact of VKORC1, CYP2C9, CYP2C19 gene polymorphisms and gene–gene interactions on warfarin therapy

Association between CYP2C9 and VKORC1 genetic polymorphisms and efficacy and safety of warfarin in Chinese patients

OBJECTIVES

Genetic variation has been a major contributor to interindividual variability of warfarin dosage requirement. The specific genetic factors contributing to warfarin bleeding complications are largely unknown, particularly in Chinese patients. In this study, 896 Chinese patients were enrolled to explore the effect of CYP2C9 and VKORC1 genetic variations on both the efficacy and safety of warfarin therapy.

METHODS AND RESULTS

Univariate analyses unveiled significant associations between two specific single nucleotide polymorphisms rs1057910 in CYP2C9 and rs9923231 in VKORC1 and stable warfarin dosage ( P  < 0.001). Further, employing multivariate logistic regression analysis adjusted for age, sex and height, the investigation revealed that patients harboring at least one variant allele in CYP2C9 exhibited a heightened risk of bleeding events compared to those with the wild-type genotype (odds ratio = 2.16, P  = 0.04). Moreover, a meta-analysis conducted to consolidate findings confirmed the associations of both CYP2C9 (rs1057910) and VKORC1 (rs9923231) with stable warfarin dosage. Notably, CYP2C9 variant genotypes were significantly linked to an increased risk of hemorrhagic complications ( P  < 0.00001), VKORC1 did not demonstrate a similar association.

CONCLUSION

The associations found between specific genetic variants and both stable warfarin dosage and bleeding risk might be the potential significance of gene detection in optimizing warfarin therapy for improving patient efficacy and safety.

Association between gene polymorphisms and initial warfarin therapy in patients after heart valve surgery

BACKGROUND

Warfarin is widely used for the prevention and treatment of thrombotic events. This study aimed to examine the influence of gene polymorphisms on the early stage of warfarin therapy in patients following heart valve surgery.

METHODS

Nine single nucleotide polymorphisms were genotyped using microarray chips, categorizing patients into three groups: normal responders (Group I), sensitive responders (Group II), and highly sensitive responders (Group III). The primary clinical outcomes examined were time in therapeutic range (TTR) and international normalized ratio (INR) variability. To investigate potential influencing factors, a generalized linear regression model was employed.

RESULTS

Among 734 patients, the prevalence of CYP2C9*3-1075A > C, CYP2C19*3-636G > A, and CYP2C19*17-806C > T variants were 11.2%, 9.9%, and 1.9% of patients, respectively. VKORC1-1639G > A or the linked -1173C > T variant was observed in 99.0% of the patients. Generalized linear model analysis revealed an impact of sensitivity grouping on INR variability. Compared to Group I, Group II showed higher TTR values (p = 0.023), while INR variability was poorer in Group II (p < 0.001) and Group III (p < 0.001). Individual gene analysis identified significant associations between CYP2C9*3-1075A > C (p < 0.001), VKORC1-1639G > A or the linked -1173 C > T (p = 0.009) and GGCX-3261G > A (p = 0.019) with INR variability.

CONCLUSION

The genotypes of CYP2C9, VKORC1, and GGCX were found to have a significant impact on INR variability during the initial phase of warfarin therapy. However, no significant association was observed between TTR and gene polymorphisms. These findings suggest that focusing on INR variability is crucial in clinical practice, and preoperative detection of gene polymorphisms should be considered to assist in the initiation of warfarin therapy.

Influence of polymorphisms in CYP2C9, VKORC1, MDR1 and APOE genes on the warfarin maintenance dose in Brazilian patients

Background: Polymorphisms in the CYP2C9, VKORC1, MDR1 and APOE genes may impact warfarin dose. Aim: To investigate the influence of sociodemographic, clinical factors and polymorphisms *1, *2 and *3 for CYP2C9, -1639G>A for VKORC1, 3435C>T for MDR1, and ϵ2, ϵ3 and ϵ4 for APOE genes on the mean weekly warfarin maintenance dose in adults. Methods: This cross-sectional study recruited a calculated sample of 315 patients in three anticoagulation clinics in Brazil. A model containing the variables significantly associated with warfarin dose was estimated. Results: The mean age of patients was 64.1 ± 13.1 years, with 173 (54.9%) women. Age, use of amiodarone, genotype VKORC1 GA, genotype VKORC1 AA, genotypes CYP2C9*1/*2 or *1/*3 and genotypes CYP2C9*2/*2 or *2/*3 or *3/*3 were associated with a reduced warfarin dose. Conclusion: This study pointed out factors that could impact the management of oral anticoagulation.

Impact of CYP2C19 gene polymorphisms on warfarin dose requirement: a systematic review and meta-analysis

Background: Various genetic factors influence warfarin maintenance dose. Methods: A literature search was performed on PubMed, Embase and the Cochrane Library, and a meta-analysis to analyze the impact of CYP2C19 polymorphisms on warfarin maintenance dose was conducted. Results: From nine studies encompassing 1393 patients, three CYP2C19 SNPs were identified: rs4244285, rs4986893 and rs3814637. Warfarin maintenance dose was significantly reduced by 10% in individuals with the rs4986893 A allele compared with the GG carriers and was 34%, 16% and 18% lower in patients with rs3814637 TT and CT genotypes and T allele, respectively, than that in CC carriers. No significant dose difference was observed among the rs4244285 genotypes. Conclusion: CYP2C19 rs4986893 and rs3814637 are associated with significantly reduced warfarin dose requirements.

LRP1 polymorphisms associated with warfarin stable dose in Chinese patients: a stepwise conditional analysis

Aim: The aim of this study was to investigate whether variability in warfarin stable dose (WSD) could be influenced by vitamin K-related polymorphisms in patients with heart valve replacement. Patients & methods: Twenty-nine vitamin K-related SNPs in 208 patients who initially took warfarin and achieved WSD were genotyped. Results: After conducting conditional analysis for both VKORC1 -1639G>A and CYP2C9*3, LRP1 rs1800139 and LRP1 rs1800154 were significantly associated with WSD (p = 0.007 and p = 0.015, respectively). Multivariate analysis showed that LRP1 rs1800139 accounted for 5.9% WSD variability. Conclusion: Our results suggest that a novel vitamin K-related gene, LRP1, exerts a relevant influence on WSD, independent of VKORC1 -1639G>A and CYP2C9*3.