Coagulation
Hereditary bleeding disorders
Factor V deficiency
Last author update: 1 August 2010
Last staff update: 16 September 2020
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PubMed Search: Factor V deficiency
Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Laboratory | Prognostic factors | Case reports | Treatment | Differential diagnosis | Additional referencesCite this page: Crookston K, Rosenbaum LS, Gober-Wilcox J. Factor V deficiency. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/coagulationfactorVdef.html. Accessed January 10th, 2025.
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
Terminology
- 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)
Epidemiology
- Rare, incidence of less than 1 per 1,000,000 in the homozygous form
- Over 200 cases have been described in the literature
Sites
- 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
Pathophysiology
- 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)
Laboratory
- 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)
Treatment
- 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
- Acquired factor V deficiency: seen in liver disease or patients with DIC
- Acquired factor V inhibitors
- Combined factor VIII/factor V deficiency
