|A service of the U.S. National Library of Medicine®|
Factor V deficiency
On this page:
Reviewed May 2013
What is factor V deficiency?
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.
How common is factor V deficiency?
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.
What genes are related to factor V deficiency?
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.
Read more about the F5 gene.
How do people inherit 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.
Where can I find information about diagnosis or management of factor V deficiency?
These resources address the diagnosis or management of factor V deficiency and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about factor V deficiency?
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.
What other names do people use for factor V deficiency?
What if I still have specific questions about factor V deficiency?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding factor V deficiency?
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.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.