Hereditary bleeding disorders

Factor V deficiency

Last author update: 1 August 2010
Last staff update: 16 September 2020

Copyright: 2002-2016,, Inc.

PubMed Search: Factor V deficiency

Kendall Crookston, M.D., Ph.D.
Julie Kim Harrington, M.D.
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Cite this page: Crookston K, Rosenbaum LS, Gober-Wilcox J. Factor V deficiency. website. Accessed June 2nd, 2023.
Definition / general
  • Factor V deficiency is a rare congenital bleeding disorder that is inherited as an autosomal recessive trait and is characterized by decreased or absent factor V activity
  • Also called autoprothrombin I deficiency, Owrens disease, labile factor deficiency or parahemophilia (severe deficiency)

  • Deficiency classified as either:
    • Type I: both reduced antigen level and activity (quantitative defect)
    • Type II: normal or mildly reduced antigen level and reduced activity (qualitative defect)
  • Rare, incidence of less than 1 per 1,000,000 in the homozygous form
  • Over 200 cases have been described in the literature
  • Autosomal recessive trait with variable heterozygote expressivity
  • There have been 56 mutations described including insertion/deletion, missense, splice site and nonsense mutations (in order of decreasing frequency)
  • Parental consanguinity is often present, especially in countries (Muslim or southern India) where consanguineous marriages are common
  • Factor V is a plasma glycoprotein that is synthesized in the liver and is also present in platelet a-granules
  • Platelet factor V accounts for approximately 20% of the total body pool of factor V
  • Factor V is a plasma cofactor for the prothrombinase complex that converts prothrombin to thrombin
  • Deficiency leads to predisposition for hemorrhage, while some mutations (most notably factor V Leiden) predispose to thrombosis
Clinical features
  • May be associated with bruising, epistaxis, menorrhagia, GI / GU bleeding, umbilical stump bleeding or bleeding after surgery, trauma, dental procedures, pregnancy or circumcision
  • Severe deficiencies may resemble hemophilia A or B, and are associated with intracranial hemorrhage; however hemarthroses are not as common
  • There are mild, moderate and severe forms
  • Patients with mild to moderate deficiency (> 20 - 30%) have a heterozygous genotype and are usually asymptomatic and may not be diagnosed until adulthood
  • Patients with severe deficiency (< 10%) have either homozygous or compound heterozygous genotype and typically present within the first 6 months of life
  • Levels dont always correlate with severity of symptoms
  • Complications of treatment include the development of factor V alloantibodies (inhibitors)
  • Prolonged PT / PTT with correction after mixing study with normal pooled plasma
  • Normal thrombin time
  • Specific clot-based factor V assay for diagnosis
Prognostic factors
  • Prognosis is good for most patients with factor V deficiency
  • Most severe cases have been in patients who present in the perinatal period with intracranial bleeding
Case reports
  • Severe gestational factor V deficiency presenting with intracranial hemorrhage detected by ultrasound (Haemophilia 2007;13:432)
  • Since there are no factor V concentrates available, fresh frozen plasma (FFP) is the mainstay of treatment (15 to 20 mL/kg followed by smaller amounts, such as 5 mL/kg every 12 hours, adjusting the dosage on the basis of Factor V levels, PT and APTT)
  • Cryoprecipitate and prothrombin complex concentrates do not contain factor V
  • For refractory patients or patients with inhibitors, prothrombin complex concentrates, recombinant activated FVIIa and platelet transfusions have been successfully used
  • Patients with inhibitors may need immunosuppression
Differential diagnosis
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