Congenital factor V deficiency

Congenital factor V deficiency, also known as Owren disease or parahemophilia, is a rare inherited bleeding disorder caused by a deficiency or dysfunction of coagulation factor V (also called labile factor or proaccelerin). Factor V plays a critical role in the blood clotting cascade, serving as an essential cofactor for factor Xa in the conversion of prothrombin to thrombin. Without adequate functional factor V, the body's ability to form stable blood clots is significantly impaired. The severity of bleeding symptoms generally correlates with the level of residual factor V activity. Patients with severe deficiency (factor V levels below 1%) may present in the neonatal period or early childhood with serious bleeding manifestations including intracranial hemorrhage, umbilical cord bleeding, and gastrointestinal hemorrhage. More moderate forms may present with epistaxis (nosebleeds), easy bruising, menorrhagia (heavy menstrual bleeding) in women, prolonged bleeding after surgery or dental procedures, and mucocutaneous bleeding. Joint bleeding (hemarthrosis) and muscle hematomas, while characteristic of other clotting factor deficiencies, are less common in factor V deficiency but can occur in severe cases. There is no factor V concentrate currently available for treatment. Management of bleeding episodes and surgical prophylaxis relies primarily on fresh frozen plasma (FFP), which contains factor V. Platelet transfusions may also be beneficial since platelets contain approximately 20% of the body's factor V in their alpha granules. Antifibrinolytic agents such as tranexamic acid can be used as adjunctive therapy, particularly for mucosal bleeding. Women with heavy menstrual bleeding may benefit from hormonal therapies. Patients are advised to avoid antiplatelet medications and to coordinate with a hematologist for any planned surgical or dental procedures.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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