中文摘要：

To the editor Warfarin is a commonly used anticoagulant with a narrow therapeutic range and risk of hemorrhagic complications.[1] After CYP2C9 and VKORC1, CYP4F2 was confirmed as the third principle genetic determinant of warfarin dose variability.[2,3] CYP4F2 functions as a vitamin K1 (VK1) oxidase, a counterpart to vitamin K oxidize reductase (encoded by VKORC1) in limiting excessive accumulation of VK1 in vitamin K cycle.[4]

英文摘要：

Warfarin is a commonly used anticoagulant with a narrow therapeutic range and risk of hemorrhagic complications. After CYP2C9 and VKORC1, CYP4F2 was confirmed as the third principle genetic determinant of warfarin dose variability.