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Genetics Home Reference: your guide to understanding genetic conditions
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F5

Reviewed May 2013

What is the official name of the F5 gene?

The official name of this gene is “coagulation factor V (proaccelerin, labile factor).”

F5 is the gene's official symbol. The F5 gene is also known by other names, listed below.

What is the normal function of the F5 gene?

The F5 gene provides instructions for making a protein called coagulation factor V. Coagulation factors are a group of related proteins that make up the coagulation system, a series of chemical reactions that form blood clots. After an injury, clots seal off blood vessels to stop bleeding and trigger blood vessel repair.

The factor V protein is made primarily by cells in the liver. The protein circulates in the bloodstream in an inactive form until the coagulation system is activated by an injury that damages blood vessels. When coagulation factor V is activated, it interacts with coagulation factor X. The active forms of these two coagulation factors (written as factor Va and factor Xa, respectively) form a complex that converts an important coagulation protein called prothrombin to its active form, thrombin. Thrombin then converts a protein called fibrinogen into fibrin, which is the material that forms the clot.

Coagulation factor V has another role in regulating the coagulation system through its interaction with activated protein C (APC). APC normally inactivates coagulation factor V by cutting (cleaving) it at specific sites. This inactivation slows down the clotting process and prevents clots from growing too large. When coagulation factor V is cleaved at a particular site (protein position 506), it can work with APC to inactivate factor VIIIa, which is another protein that is essential for normal blood clotting.

How are changes in the F5 gene related to health conditions?

factor V deficiency - caused by mutations in the F5 gene

At least 100 mutations in the F5 gene have been found to cause a rare bleeding disorder called factor V deficiency. These mutations prevent the production of functional coagulation factor V or significantly 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 factor V prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe. Factor V deficiency results from mutations in both copies of the F5 gene, although some people with a mutation in a single copy of the gene have mild bleeding problems.

factor V Leiden thrombophilia - caused by mutations in the F5 gene

Factor V Leiden is the name of a specific mutation in the F5 gene. This mutation changes a single protein building block (amino acid) in the factor V protein. Specifically, it replaces the amino acid arginine with the amino acid glutamine at protein position 506 (written as Arg506Gln or R506Q). Because position 506 is one of the sites where APC normally cleaves coagulation factor V, the factor V Leiden mutation slows the rate at which APC inactivates this factor. As a result, both the activated form of coagulation factor V and coagulation factor VIIIa persist longer in circulation, increasing the risk of developing an abnormal blood clot. This tendency to form abnormal clots that can block blood vessels is known as thrombophilia.

The presence of the factor V Leiden mutation in one or both copies of the F5 gene can cause thrombophilia; two copies of the mutation lead to a higher risk of developing abnormal blood clots than a single copy of the mutation.

other disorders - increased risk from variations of the F5 gene

Some people have the factor V Leiden mutation (Arg506Gln) in one copy of the F5 gene and a mutation associated with factor V deficiency in the other copy of the gene in each cell. The factor V Leiden mutation results in the production of an abnormal coagulation factor V protein that is resistant to inactivation by APC, while the other mutation prevents the production of any coagulation factor V protein. This combination of mutations is associated with an increased risk of abnormal blood clots similar to the risk associated with having two copies of the factor V Leiden mutation. This rare condition is known as pseudohomozygous APC resistance or pseudohomozygous factor V Leiden.

The factor V Leiden mutation is involved in some cases of a condition known as Budd-Chiari syndrome. This condition is characterized by a blockage of blood flow from the liver, which can be caused by a blood clot. People with thrombophilia, including that caused by the factor V Leiden mutation, have an increased risk of developing Budd-Chiari syndrome. Signs and symptoms of the syndrome include pain in the abdomen, an abnormally large liver (hepatomegaly), and accumulation of fluid in the lining of the abdomen (ascites).

Where is the F5 gene located?

Cytogenetic Location: 1q23

Molecular Location on chromosome 1: base pairs 169,511,953 to 169,586,530

The F5 gene is located on the long (q) arm of chromosome 1 at position 23.

The F5 gene is located on the long (q) arm of chromosome 1 at position 23.

More precisely, the F5 gene is located from base pair 169,511,953 to base pair 169,586,530 on chromosome 1.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about F5?

You and your healthcare professional may find the following resources about F5 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the F5 gene or gene products?

  • blood coagulation factor V
  • factor V

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding F5?

amino acid ; arginine ; ascites ; blood clotting ; blood coagulation ; blood coagulation factor ; cell ; clotting ; coagulation ; coagulation factors ; deficiency ; factor V deficiency ; fibrin ; fibrinogen ; gene ; glutamine ; injury ; mutation ; parahemophilia ; protein ; syndrome ; thrombin ; thrombophilia

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Asselta R, Peyvandi F. Factor V deficiency. Semin Thromb Hemost. 2009 Jun;35(4):382-9. doi: 10.1055/s-0029-1225760. Epub 2009 Jul 13. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19598066?dopt=Abstract)
  • Asselta R, Tenchini ML, Duga S. Inherited defects of coagulation factor V: the hemorrhagic side. J Thromb Haemost. 2006 Jan;4(1):26-34. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16409445?dopt=Abstract)
  • Brugge JM, Simioni P, Bernardi F, Tormene D, Lunghi B, Tans G, Pagnan A, Rosing J, Castoldi E. Expression of the normal factor V allele modulates the APC resistance phenotype in heterozygous carriers of the factor V Leiden mutation. J Thromb Haemost. 2005 Dec;3(12):2695-702. (http://www.ncbi.nlm.nih.gov/pubmed/16359508?dopt=Abstract)
  • Castoldi E, Rosing J. Factor V Leiden: a disorder of factor V anticoagulant function. Curr Opin Hematol. 2004 May;11(3):176-81. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15257017?dopt=Abstract)
  • Colak Y, Karasu Z, Oruc N, Can C, Balým Z, Akarca U, Gunsar F, Ersoz G, Tokat Y, Batur Y. Hyperhomocysteinaemia and factor V Leiden mutation are associated with Budd-Chiari syndrome. Eur J Gastroenterol Hepatol. 2006 Aug;18(8):917-20. (http://www.ncbi.nlm.nih.gov/pubmed/16825912?dopt=Abstract)
  • Cutler JA, Patel R, Rangarajan S, Tait RC, Mitchell MJ. Molecular characterization of 11 novel mutations in patients with heterozygous and homozygous FV deficiency. Haemophilia. 2010 Nov;16(6):937-42. doi: 10.1111/j.1365-2516.2010.02330.x. (http://www.ncbi.nlm.nih.gov/pubmed/20546033?dopt=Abstract)
  • Duga S, Asselta R, Tenchini ML. Coagulation factor V. Int J Biochem Cell Biol. 2004 Aug;36(8):1393-9. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15147718?dopt=Abstract)
  • Janssen HL, Meinardi JR, Vleggaar FP, van Uum SH, Haagsma EB, van Der Meer FJ, van Hattum J, Chamuleau RA, Adang RP, Vandenbroucke JP, van Hoek B, Rosendaal FR. Factor V Leiden mutation, prothrombin gene mutation, and deficiencies in coagulation inhibitors associated with Budd-Chiari syndrome and portal vein thrombosis: results of a case-control study. Blood. 2000 Oct 1;96(7):2364-8. (http://www.ncbi.nlm.nih.gov/pubmed/11001884?dopt=Abstract)
  • Lak M, Sharifian R, Peyvandi F, Mannucci PM. Symptoms of inherited factor V deficiency in 35 Iranian patients. Br J Haematol. 1998 Dec;103(4):1067-9. (http://www.ncbi.nlm.nih.gov/pubmed/9886321?dopt=Abstract)
  • Mann KG, Kalafatis M. Factor V: a combination of Dr Jekyll and Mr Hyde. Blood. 2003 Jan 1;101(1):20-30. Epub 2002 Aug 8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12393635?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/2153)
  • Nicolaes GA, Dahlbäck B. Factor V and thrombotic disease: description of a janus-faced protein. Arterioscler Thromb Vasc Biol. 2002 Apr 1;22(4):530-8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/11950687?dopt=Abstract)
  • Ornstein DL, Cushman M. Cardiology patient page. Factor V Leiden. Circulation. 2003 Apr 22;107(15):e94-7. (http://www.ncbi.nlm.nih.gov/pubmed/12707252?dopt=Abstract)
  • Rosendorff A, Dorfman DM. Activated protein C resistance and factor V Leiden: a review. Arch Pathol Lab Med. 2007 Jun;131(6):866-71. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17550313?dopt=Abstract)
  • Segers K, Dahlbäck B, Nicolaes GA. Coagulation factor V and thrombophilia: background and mechanisms. Thromb Haemost. 2007 Sep;98(3):530-42. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17849041?dopt=Abstract)
  • Vos HL. Inherited defects of coagulation Factor V: the thrombotic side. J Thromb Haemost. 2006 Jan;4(1):35-40. Epub 2005 Oct 25. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16246256?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: May 2013
Published: October 9, 2014