Abstract: AIM: To study the distribution of CYP2C9*3 and VKORC1-1639G>A gene polymorphism in Han population in Anhui province and their influence on the stable dose of warfarin. METHODS: The blood samples of 1 169 patients from 6 tertiary general hospitals in 5 areas of Anhui province from January 2020 to December 2021 were selected, the genotype of CYP2C9*3 and VKORC1-1639G>A was detected by fluorescent staining in situ hybridization technique. RESULTS: The distribution of CYP2C9*3 genotypes in 1 169 patients: the frequencies of AA, AC and CC genes were 90.16%, 9.24% and 0.60%, respectively; The distribution of VKORC1 genotype: the frequencies of AA, AG and GG genes were 84.26%, 14.71% and 1.03% respectively; There was no significant difference between the two genotypes in gender, age and regional distribution (P>0.05). The average daily warfarin dose of CYP2C9*3 AA genotype in 755 patients with stable warfarin dose was (3.02±0.59) mg/d, which was significantly higher than patients with AC genotype and CC genotype; The average daily warfarin dose of patients with VKORC1-1639AA  genotype was (2.72±0.40) mg/d, which was significantly lower than that of patients with AG genotype and GG genotype (P<0.05). And the difference was statistically significant (P<0.05); There are significant differences in gender, age and clinical diagnosis between patients with stable dose of warfarin and those without stable dose (P<0.05). CONCLUSION: CYP2C9 and VKORC1 genotypes are associated with the stable dose of warfarin. Clinical anticoagulation therapy guided by CYP2C9 and VKORC1 genotypes can provide guidance for individualized medication of warfarin.

Key words: warfarin, CYP2C9*3, VKORC1-1639G>A, gene polymorphism, individualized medication