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Updated: May 30, 2026

A Method to Study the C924T Polymorphism of the Thromboxane A2 Receptor Gene
Published on: April 1, 2019
[Possible application of pharmacogenomics to warfarin therapy]
1Department of Laboratory Medicine, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan. murata@sc.itc.keio.ac.jp
Abstract:
Vitamin K-dependent gamma-carboxylation system is crucial to generate active coagulation factors. It consists of gamma-Glutamylcarboxylase (GGCX) and vitamin K-epoxide reductase (VKOR). Warfarin is an anticoagulant that blocks VKOR. Recent studies have shown that genetic variations in a subunit of VKOR complex, VKORC1, and in cytochrome P 450 (CYP) 2C9 genes are strong determinants of individuals' warfarin sensitivity. Algorithms have been proposed to predict warfarin doses, and about 55% of the variance in warfarin dose could be attributed to variations in the VKORC1 and CYP2C9 genes together with age, sex, body-surface area, and presence or absence of heart valve replacement. Contributions of polymorphisms in VKORC1 and CYP2C9 to inter-individual differences of warfarin dose, however, are different among races. Studies have shown that potential clinical and economic benefits of CYP2C9/VKORC1 genotype-guided dosing are only marginal. Thus, evidence is still limited and application of warfarin pharmacogenomics to clinical practice at present needs careful consideration.
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