Resistance to activated protein C and a novel factor V gene mutation

A novel mutation in the factor V gene of the blood coagulation cascade has been identified recently. The mutation confers a lifelong hypercoagulable state, and carriers of the mutation have an approximate eightfold increase in relative risk for the development of venous thrombosis. Carriers of the mutation manifest a laboratory coagulation defect termed resistance to activated protein C (APC). This article reviews the discovery of APC resistance, the identification of the factor V gene mutation, and laboratory approaches to their diagnosis.