Warfarin is the most widely used oral anticoagulant in the world for patients with venous thrombosis, pulmonary embolism, chronic atrial fibrillation, and prosthetic heart valves. Approximately 30 genes contribute to therapeutic effects of warfarin, and genetic polymorphisms in these genes may modulate its anticoagulant activity. In contrast to monogenic pharmacogenetic traits, warfarin drug re...