Association between genes polymorphisms in CYP4F2 (rs2108622), VKORC1 (rs9923231,rs2884737), CYP2C9*2 (rs1799853) for required therapeutic dose of warfarin in patients referred to cardiovascular centers in Tehran Province

Warfarin is the most commonly prescribed anticoagulant drug for treating thromboembolic events. There is a variation in dose requirements for each individual due to nongenetic factors and gene polymorphisms. In this study, we performed Tetra-ARMS PCR molecular technique in order to investigate the association between 5 gene polymorphisms and patient characteristics with warfarin dose requirements in all Iranian ethnic groups.  

This study was done on 68 Iranian patients on warfarin treatment who attended the cardiovascular centers in Tehran Province for regular INR monitoring. Genotyping of VKORC1 (rs9923231 and rs2884737), CYP4F2, and CYP2C9*3 were performed using Tetra-Arms-PCR and conventional PCR was done for the detection of CYP2C9*2 (rs1799853) SNP. Multiple regression model was performed for statistical analyses and P<0.05 was considered as the significance level.

Of 5 SNPs, VKORC1 rs9923231, CYP2C9*2, and CYP2C9*3 variants alleles had a significantly lower mean warfarin daily dose compared with the wild-type genotypes, whereas no significant association was seen between VKORC1 rs288473710, CYP4F2, and warfarin maintenance doses. Furthermore, despite a significant association between patients’ age and warfarin dose (p=0.021), it was not statistically significant for other demographic characteristics.

It can be concluded that VKORC1 rs9923231, CYP2C9*2, and CYP2C9*3 gene polymorphisms and patients’ age had a significant effect on warfarin dose. The new warfarin-dosing algorithm was developed based on VKORC1 rs9923231, CYP2C9*2, and CYP2C9*3 genotypes for predicting the required dose of warfarin.