Congenital Factor V Deficiency
Congenital factor V deficiency is an inherited bleeding disorder due to reduced plasma levels of factor V (FV) and characterized by mild to severe bleeding symptoms.
Prevalence of homozygous forms is estimated at 1/1,000,000. Both sexes are equally affected.
Congenital FV deficiency can manifest at any age, with the most severe forms manifesting early in life. Common clinical signs include epistaxis, bruising, mucosal bleeding, soft tissue bleeding, and hemarthrosis. Excessive and prolonged bleeding during or following surgery, delivery or trauma are frequent. Women may present with menorrhagia. In severe forms of the disease, there can be a risk of intracranial, pulmonary or gastrointestinal bleedings. The severity of the bleeding manifestations correlates with the FV levels.
Congenital FV deficiency is caused by mutations in the F5 gene (1q23) controlling the production of plasma FV.
Diagnosis is based on prolonged prothrombin and activated partial thromboplastin times (PT, aPTT) and on low FV levels measured using a PT based assay. The bleeding time (BT) may be prolonged. Molecular testing is available, but unnecessary for diagnosis.
Differential diagnoses include factor VIII deficiency, and combined deficiency of factor V and factor VIII (see these terms).
Transmission is autosomal recessive.
Management and treatment
Fresh frozen plasma (FFP) is the only treatment as FV concentrates are not available. In acute cases of severe bleeding, the addition of platelet concentrates may be helpful.
Prognosis is good with early diagnosis and adequate treatment.