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Factor V deficiency is a rare bleeding disorder. The signs and symptoms of this condition can begin at any age, although the most severe cases are apparent in childhood. Factor V deficiency commonly causes nosebleeds; easy bruising; bleeding under the skin; bleeding of the gums; and prolonged or excessive bleeding following surgery, trauma, or childbirth. Women with factor V deficiency can have heavy or prolonged menstrual bleeding (menorrhagia). Bleeding into joint spaces (hemarthrosis) can also occur, although it is rare. Severely affected individuals have an increased risk of bleeding inside the skull (intracranial hemorrhage), in the lungs (pulmonary hemorrhage), or in the gastrointestinal tract, which can be life-threatening.
Factor V deficiency affects an estimated 1 in 1 million people. This condition is more common in countries such as Iran and southern India, where it occurs up to ten times more frequently than in western countries.
Factor V deficiency is usually caused by mutations in the F5 gene, which provides instructions for making a protein called coagulation factor V. This protein plays a critical role in the coagulation system, which is a series of chemical reactions that forms blood clots in response to injury. F5 gene mutations that cause factor V deficiency prevent the production of functional coagulation factor V or severely reduce the amount of the protein in the bloodstream. People with this condition typically have less than 10 percent of normal levels of coagulation factor V in their blood; the most severely affected individuals have less than 1 percent. A reduced amount of functional coagulation factor V prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe.
Very rarely, a form of factor V deficiency is caused by abnormal antibodies that recognize coagulation factor V. Antibodies normally attach (bind) to specific foreign particles and germs, marking them for destruction, but the antibodies in this form of factor V deficiency attack a normal human protein, leading to its inactivation. These cases are called acquired factor V deficiency and usually occur in individuals who have been treated with substances that stimulate the production of anti-factor V antibodies, such as bovine thrombin used during surgical procedures. There is no known genetic cause for this form of the condition.
Changes in this gene are associated with factor V deficiency.
Factor V deficiency is inherited in an autosomal recessive pattern, which means both copies of the F5 gene in each cell have mutations. Individuals with a mutation in a single copy of the F5 gene have a reduced amount of coagulation factor V in their blood and can have mild bleeding problems, although most have no related health effects.
These resources address the diagnosis or management of factor V deficiency and may include treatment providers.
You might also find information on the diagnosis or management of factor V deficiency in Educational resources (/condition/factor-v-deficiency/show/Educational+resources) and Patient support (/condition/factor-v-deficiency/show/Patient+support).
General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).
To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
You may find the following resources about factor V deficiency helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/gard).
autosomal ; autosomal recessive ; cell ; clotting ; coagulation ; congenital ; deficiency ; factor V deficiency ; gastrointestinal ; gene ; gums ; hemorrhage ; hereditary ; inherited ; injury ; joint ; labile factor deficiency ; mutation ; Owren disease ; parahemophilia ; proaccelerin deficiency ; protein ; pulmonary ; recessive ; surgery ; surgical ; thrombin ; trauma
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (/glossary).
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