Korean J Med.  2013 Jul;85(1):87-91.

A Case of Warfarin-Induced Bleeding in a Patient with CYP2C9 and VKORC1 Gene Polymorphism, Detected by a Point-of-Care Gene Test Device

• Kim BS
• Lee DH
• Park HK
• Kim M
• Kim SH
• Kim KH
• Kim MH

Abstract

A 69-year-old female Korean patient was initially prescribed warfarin for the prevention of systemic thromboembolism due to atrial fibrillation. One month later, multiple bruises and subcutaneous hematomas were evident, and laboratory testing revealed a prolonged prothrombin time (PT) of > 106s. After admission, the PT was corrected via fresh frozen plasma transfusion and intravenous vitamin K infusion. We sought to determine the cause of the PT prolongation, suspecting that genetic cause may have had an effect on the variation in the warfarin dose requirement. A point-of-care gene test device (Verigene(R) system; Nanosphere, Northbrook, IL) revealed CYP2C9*1/*3 heterozygosity and a VKORC1 A/A single nucleotide polymorphism. Although it is well established that CYP2C9 or VKORC1 gene polymorphisms can influence warfarin dose requirements, they can be easily neglected, with detrimental outcomes. Through our experience with CYP2C9 and VKORC1 polymorphism causing bleeding complications during warfarin treatment, we aim to emphasize the importance of pharmacogenetic testing to avoid this potential oversight.

Keyword

Warfarin; Pharmacogenetics; Point-of-care systems

MeSH Terms

Atrial Fibrillation
Contusions
Female
Hematoma
Hemorrhage
Humans
Nanospheres
Pharmacogenetics
Plasma
Point-of-Care Systems
Polymorphism, Single Nucleotide
Prothrombin Time
Thromboembolism
Vitamin K
Warfarin
Vitamin K
Warfarin