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The official name of this gene is “coagulation factor VIII, procoagulant component.”
F8 is the gene's official symbol. The F8 gene is also known by other names, listed below.
The F8 gene provides instructions for making a protein called coagulation factor VIII. Coagulation factors are a group of related proteins that are essential for the formation of blood clots. After an injury, clots protect the body by sealing off damaged blood vessels and preventing further blood loss.
Coagulation factor VIII is made chiefly by cells in the liver. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs. In response to injury, coagulation factor VIII is activated and separates from von Willebrand factor. The active protein (sometimes written as coagulation factor VIIIa) interacts with another coagulation factor called factor IX. This interaction sets off a chain of additional chemical reactions that form a blood clot.
Mutations in the F8 gene cause hemophilia A, the most common form of this bleeding disorder. More than 1,300 alterations in this gene have been identified. Some of these mutations change single DNA building blocks (base pairs) in the gene, while others delete or insert multiple base pairs. The most common mutation in people with severe hemophilia A is a rearrangement of genetic material called an inversion. This inversion involves a large segment of the F8 gene.
Mutations in the F8 gene lead to the production of an abnormal version of coagulation factor VIII or reduce the amount of this protein. The altered or missing protein cannot participate effectively in the blood clotting process. As a result, blood clots cannot form properly in response to injury. These problems with blood clotting lead to excessive bleeding that can be difficult to control. Some mutations, such as the large inversion described above, almost completely eliminate the activity of coagulation factor VIII and result in severe hemophilia. Other mutations reduce but do not eliminate the protein's activity, resulting in mild or moderate hemophilia.
Cytogenetic Location: Xq28
Molecular Location on the X chromosome: base pairs 154,835,787 to 155,026,933
The F8 gene is located on the long (q) arm of the X chromosome at position 28.
More precisely, the F8 gene is located from base pair 154,835,787 to base pair 155,026,933 on the X chromosome.
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 F8 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.
blood clotting ; clotting ; coagulation ; coagulation factors ; DNA ; gene ; hemostasis ; injury ; intron ; inversion ; molecule ; mutation ; protein ; rearrangement
You may find definitions for these and many other terms in the Genetics Home Reference 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.