Factor V is an essential component in the blood coagulation cascade. Inherited or acquired deficiencies in factor V are rare causes of bleeding disorders. Factor V deficiency is also known as Owren disease. Factor V deficiency has also been called parahemophilia, since hemarthrosis can occur with severe deficiencies and with increased bleeding time. Factor V Leiden is a mutation of one of the clotting factors in the blood called factor V. This mutation can increase your chance of developing abnormal blood clots (thrombophilia), usually in your veins. Factor V is an essential component in the blood coagulation cascade. Factor V is synthesized in the liver and possibly in megakaryocytes. Factor V circulates in an inactive form. During coagulation, factor V is converted to the active cofactor, factor Va, via limited proteolysis by the serine protease a-thrombin. Factor Va and activated factor Xa form the prothrombinase complex. The prothrombinase complex is responsible for the rapid conversion of the zymogen prothrombin to the active serine protease a-thrombin.
Most people who have factor V Leiden never develop signs or symptoms. The first indication that you have the disorder may be the development of a blood clot (thrombosis). This is known as deep vein thrombosis (DVT). Deep vein thrombosis may not cause any symptoms. If signs and symptoms do occur, they commonly affect your legs, including swelling of your ankles and feet. Other signs and symptoms may include: Pain, Significant swelling, Redness, Warmth etc. Doctors generally use blood-thinning (anticoagulant) medications, such as warfarin (Coumadin, Jantoven), heparin or low molecular weight heparin to treat people who develop blood clots. Heparin (anticoagulant medication works more quickly than warfarin does, comes in the form of injectable) Warfarin (anticoagulant comes in pill form, so it's easier to take than heparin.)
Only 150 cases of congenital factor V deficiency have been reported worldwide since 1943. Homozygous factor V deficiency is rare, occurring in approximately 1 per million population. The severity of factor V deficiency varies from bruising to lethal hemorrhage. Factor V deficiency affects males and females with equal frequency. Factor V deficiency affects all ages. The age at presentation indirectly varies with the severity of disease.