Multi-site Investigation of Genetic Determinants of Warfarin Dose Variability in Latinos

Abstract

We conducted a multi-site investigation of genetic determinants of warfarin dose variability in Latinos from the U.S. and Brazil. Patients from four institutions in the United States (n = 411) and Brazil (n = 663) were genotyped forVKORC1c.-1639G> A, commonCYP2C9variants,CYP4F2*3, andNQO1*2. Multiple regression analysis was used in the U.S. cohort to test the association between warfarin dose and genotype, adjusting for clinical factors, with further testing in an independent cohort of Brazilians. In the U.S. cohort,VKORC1andCYP2C9variants were associated with lower warfarin dose (beta = -0.29,P < 2.0 x 10(-16); beta = -0.21,P = 4.7 x 10(-7), respectively) whereasCYP4F2andNQO1variants were associated with higher dose (beta = 0.10,P = 2 x 10(-4); beta = 0.10,P = 0.01, respectively). Associations withVKORC1(beta = -0.14,P = 2.0 x 10(-16)),CYP2C9(beta = -0.07,P = 5.6 x 10(-10)), andCYP4F2(beta = 0.03,P = 3 x 10(-3)), but notNQO1*2(beta = 0.01,P = 0.30), were replicated in the Brazilians, explaining 43-46% of warfarin dose variability among the cohorts from the U.S. and Brazil, respectively. We identified genetic associations with warfarin dose requirements in the largest cohort of ancestrally diverse, warfarin-treated Latinos from the United States and Brazil to date. We confirmed the association of variants inVKORC1,CYP2C9, andCYP4F2with warfarin dose in Latinos from the United States and Brazil.