Parahemophilia: new insights into factor v deficiency.

Blood coagulation factor V (FV) plays a pivotal role in blood coagulation. It is found in both plasma and in platelets and has a profound impact on thrombin generation. Deficiency of this clotting factor due to inherited or acquired conditions results in a broad spectrum of bleeding symptoms. Surprisingly however, some patients with undetectable levels of FV experience relatively mild bleeding. The aim of this review is to highlight this rare coagulation factor disorder and touch upon its clinical manifestations, diagnosis, and treatment. Furthermore, recent advances that shed new light on the importance of platelet FV and other modifiers which influence bleeding tendencies in severe FV deficiency will be discussed. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.