Application of rapid genotyping of Warfarin individualized pharmacogenetic variants in Warfarin therapy

Abstract

Abstract Warfarin is the most widely used oral anticoagulant in clinical practice. The cytochrome P450 2C9 (CYP2C9), vitamin K epoxide reductase complex 1 (VKORC1), and cytochrome P450 4F2 (CYP4F2) genotypes are associated with warfarin dose requirements in China. Accurate genotyping is vital for obtaining reliable genotype-guided warfarin dosing information. The current method for individualized dosing gene polymorphism detection for warfarin has the disadvantages of being easily contaminated, time-consuming, expensive, and unsuitable for clinical use. Herein, we present a novel application, a multiplex fluorescent melting curve assay of whole-blood direct amplification of nested polymerase chain reaction (PCR), to genotyping single-nucleotide polymorphism (SNPs) rapidly that affect warfarin efficacy. This method requires only 1 µL of whole blood, no DNA extraction, takes less than 2 h, costs less than $1, and is able to accurately distinguish between different SNP sites. Polymorphic loci were detected in whole blood specimens of 181 clinical warfarin-administered patients through nested blood direct PCR fluorescence melting curve analysis and gene sequencing. The results of the nested blood direct PCR multiplex fluorescence melting curve technology were 100% consistent with those of sequencing—characterized by high accuracy and high specificity. The allele frequencies were 94.5% for A and 5.5% for C at CYP2C9*3 (rs1057910), 7.5% for G and 92.5% for A at VKORC1 (rs9923231), and 77.1% for G and 22.9% for A at CYP4F2*3 (rs2108622). For CYP2C9*2 (rs1799853), only allele C was detected, with a frequency of 100%. Warfarin doses were lower in the CYP2C9*1*1 genotype population than in the CYP2C9*1*3 population, lower in the VKORC1 (AA) population than in the VKORC1 (GG) population, and higher in individuals with the CYP4F2*3 mutation (GA/AA) compared with those with wild-type (GG). In summary, the detection and genotyping of four polymorphic SNP sites using a multiplex fluorescent melting curve assay of whole blood direct amplification through nested PCR is highly importance for guiding personalized warfarin anticoagulant therapy.