Epidemiology
Prevalence of homozygous forms is estimated at 1/1,000,000. Both sexes are equally affected.

Clinical description
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.

Etiology
Congenital FV deficiency is caused by mutations in the F5 gene (1q23) controlling the production of plasma FV.

Diagnostic methods
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 diagnosis
Differential diagnoses include factor VIII deficiency, and combined deficiency of factor V and factor VIII (see these terms).

Genetic counseling
Transmission is autosomal recessive.

The information is taken from the website Orpha.net