The protein encoded by the VKORC1 gene is the primary target of the drug warfarin, (Coumadin), a commonly used oral anticoagulant. Several VKORC1 SNPs have been found to be predictive of warfarin dose requirement in both European and Asian-descent individuals; some are tightly linked to others and thus equivalent, at least in certain populations.
The SNPs primarily found to be associated with warfarin sensitivity include:
Polymorphisms found in another gene, cytochrome P450 2C9 (CYP2C9), also influence the metabolism of warfarin and have a smaller effect on warfarin dose. These polymorphisms are rs1799853 (CYP2C9*2) and rs1057910 (CYP2C9*3).