Factor V deficiency: a concise review

Abstract

Summary. Factor V (FV; proaccelerin or labile factor) is the plasma cofactor for the prothrombinase complex that activates prothrombin to thrombin. FV deficiency can be caused by mutations in the FV gene or in genes encoding components of a putative cargo receptor that transports FV (and factor VIII) from the endoplasmic reticulum to the Golgi. Because FV is present in platelet α‐granules as well as in plasma, low FV levels are also seen in disorders of platelet granules. Additionally, acquired FV deficiencies can occur in the setting of rheumatologic disorders, malignancies, and antibiotic use and, most frequently, with the use of topical bovine thrombin. FV levels have limited correlation with the risk of bleeding, but overall, FV‐deficient patients appear to have a less severe phenotype than patients with haemophilia A or B. The most commonly reported symptoms are bleeding from mucosal surfaces and postoperative haemorrhage. However, haemarthroses and intramuscular and intracranial haemorrhages can also occur. Because no FV‐specific concentrate is available, fresh frozen plasma remains the mainstay of treatment. Antifibrinolytics can also provide benefit, especially for mucosal bleeding. In refractory cases, or for patients with inhibitors, prothrombin complex concentrates, recombinant activated FVIIa, and platelet transfusions have been successfully used. Some patients with inhibitors may also require immunosuppression.

Factor V Deficiency Associated with Congenital Cardiac Disorder and Intracranial Hemorrage

“…The severity of the symptoms may vary within a single family. There appears to be no correlation between the severity of symptoms and the level of factor V [1,2,13].…”

“…Deficiencies of FV can also arise because of acquired inhibitors to FV and defects that affect the storage and processing of FV. FV-specific inhibitors most often develop after exposure to preparations of bovine thrombin but have also been reported in patients who have underlying rheumatologic conditions, malignancies or who were being treated with antibiotics [2]. If a low FV activity is discovered, then FV deficiency must be distinguished from consumptive coagulopathy, liver disease, combined FV and FVIII deficiencies, and an acquired FV inhibitor.…”

“…FV is synthesized primarily by the liver and levels can decrease when liver synthetic function is impaired. The source of platelet FV has not been definitively established, but evidence indicates that platelets or megakaryocytes can synthesize FV [2]. The normal range of factor V concentration is 80-120%.…”

Acquired factor V inhibitor in a patient receiving venous-venous extracorporeal membrane oxygenation for Legionella pneumonia

“…About 20% of the circulating factor V is found within platelet α granules. 1 The first reported case of congenital factor V deficiency was from Germany in 1955, 2 and to date, about 200 reported cases have been reported. 1 Congenital factor V deficiency is a rare autosomal recessive disease with a prevalence of 1 in 1 000 000.…”

“…1 The first reported case of congenital factor V deficiency was from Germany in 1955, 2 and to date, about 200 reported cases have been reported. 1 Congenital factor V deficiency is a rare autosomal recessive disease with a prevalence of 1 in 1 000 000. 1 In acquired cases, it is related to the presence of factor V inhibitor.…”