Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page:

F12 gene

coagulation factor XII

Normal Function

The F12 gene provides instructions for making a protein called coagulation factor XII. Coagulation factors are a group of related proteins that are essential for normal blood clotting (coagulation). After an injury, clots protect the body by sealing off damaged blood vessels and preventing further blood loss. Factor XII circulates in the bloodstream in an inactive form until it is activated, usually by coming in contact with damaged blood vessel walls. Upon activation, factor XII interacts with coagulation factor XI. This interaction sets off a chain of additional chemical reactions that form a blood clot.

Factor XII also plays a role in stimulating inflammation, a normal body response to infection, irritation, or other injury. When factor XII is activated, it also interacts with a protein called plasma prekallikrein. This interaction initiates a series of chemical reactions that lead to the release of a protein called bradykinin. Bradykinin promotes inflammation by increasing the permeability of blood vessel walls, allowing more fluids to leak into body tissues. This leakage causes the swelling that accompanies inflammation.

Health Conditions Related to Genetic Changes

Hereditary angioedema

At least two mutations in the F12 gene are associated with hereditary angioedema type III. These mutations change single protein building blocks (amino acids) in factor XII, which increases the activity of the protein. As a result, more bradykinin is produced, which allows additional fluids to leak through blood vessel walls. The accumulation of fluids in body tissues leads to the episodes of swelling in people with hereditary angioedema type III.

More About This Health Condition

Other disorders

Approximately 20 mutations in the F12 gene that cause factor XII deficiency have been identified. Factor XII deficiency is an inherited condition characterized by a shortage of factor XII in the blood. Individuals with this condition usually do not experience abnormal bleeding or other symptoms. Factor XII deficiency is typically discovered during routine blood testing because reduced levels of factor XII cause the blood to take longer to clot in a test tube. Most of the mutations that cause factor XII deficiency change single amino acids, which alters the structure of factor XII. It remains unclear why individuals with factor XII deficiency do not experience abnormal bleeding like those with deficiencies of other coagulation factors.

Other Names for This Gene

  • coagulation factor XII (Hageman factor)
  • FA12_HUMAN
  • HAE3
  • HAEX
  • HAF
  • Hageman factor

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Cichon S, Martin L, Hennies HC, Muller F, Van Driessche K, Karpushova A, Stevens W, Colombo R, Renne T, Drouet C, Bork K, Nothen MM. Increased activity of coagulation factor XII (Hageman factor) causes hereditary angioedema type III. Am J Hum Genet. 2006 Dec;79(6):1098-104. doi: 10.1086/509899. Epub 2006 Oct 18. Citation on PubMed or Free article on PubMed Central
  • Dewald G, Bork K. Missense mutations in the coagulation factor XII (Hageman factor) gene in hereditary angioedema with normal C1 inhibitor. Biochem Biophys Res Commun. 2006 May 19;343(4):1286-9. doi: 10.1016/j.bbrc.2006.03.092. Citation on PubMed
  • Lombardi AM, Bortoletto E, Scarparo P, Scapin M, Santarossa L, Girolami A. Genetic study in patients with factor XII deficiency: a report of three new mutations exon 13 (Q501STOP), exon 14 (P547L) and -13C>T promoter region in three compound heterozygotes. Blood Coagul Fibrinolysis. 2008 Oct;19(7):639-43. doi: 10.1097/MBC.0b013e32830d8629. Citation on PubMed
  • Martin L, Raison-Peyron N, Nothen MM, Cichon S, Drouet C. Hereditary angioedema with normal C1 inhibitor gene in a family with affected women and men is associated with the p.Thr328Lys mutation in the F12 gene. J Allergy Clin Immunol. 2007 Oct;120(4):975-7. doi: 10.1016/j.jaci.2007.07.002. Epub 2007 Sep 7. No abstract available. Citation on PubMed
  • Renne T, Gailani D. Role of Factor XII in hemostasis and thrombosis: clinical implications. Expert Rev Cardiovasc Ther. 2007 Jul;5(4):733-41. doi: 10.1586/14779072.5.4.733. Citation on PubMed
  • Schmaier AH. The elusive physiologic role of Factor XII. J Clin Invest. 2008 Sep;118(9):3006-9. doi: 10.1172/JCI36617. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.