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The official name of this gene is “coagulation factor XII (Hageman factor).”
F12 is the gene's official symbol. The F12 gene is also known by other names, listed below.
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.
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.
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.
Cytogenetic Location: 5q35.3
Molecular Location on chromosome 5: base pairs 176,829,138 to 176,836,576
The F12 gene is located on the long (q) arm of chromosome 5 at position 35.3.
More precisely, the F12 gene is located from base pair 176,829,138 to base pair 176,836,576 on chromosome 5.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about F12 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; blood clotting ; bradykinin ; clotting ; coagulation ; coagulation factors ; deficiency ; gene ; infection ; inflammation ; injury ; protein
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
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.