Impact of CYP4F2 rs2108622 on the stable warfarin dose in an admixed patient cohort.

There is controversy regarding the association between the CYP4F2 rs2108622 (V33M) polymorphism and warfarin dose requirement in white patients, and there are no data for nonwhite populations. We observed no association in self-identified white, black, or "intermediate" Brazilian patients (n = 370). The addition of the rs2108622 genotype as a variable has only a marginal effect on the predictive power of a warfarin dosing algorithm derived from this patient cohort. We conclude that prospective CYP4F2 genotyping is not justified in Brazilians who are potential candidates for warfarin therapy.