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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed May 2010

What is the official name of the F8 gene?

The official name of this gene is “coagulation factor VIII.”

F8 is the gene's official symbol. The F8 gene is also known by other names, listed below.

What is the normal function of the F8 gene?

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.

How are changes in the F8 gene related to health conditions?

hemophilia - caused by mutations in the F8 gene

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.

Where is the F8 gene located?

Cytogenetic Location: Xq28

Molecular Location on the X chromosome: base pairs 154,835,788 to 155,026,934

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The F8 gene is located on the long (q) arm of the X chromosome at position 28.

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 154,835,788 to base pair 155,026,934 on the X chromosome.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about F8?

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.

What other names do people use for the F8 gene or gene products?

  • AHF
  • antihemophilic factor
  • coagulation factor VIII, procoagulant component
  • coagulation factor VIII, procoagulant component (hemophilia A)
  • DXS1253E
  • Factor VIIIF8B
  • HEMA
  • procoagulant component

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding F8?

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.


  • Bicocchi MP, Pasino M, Lanza T, Bottini F, Boeri E, Mori PG, Molinari AC, Rosano C, Acquila M. Analysis of 18 novel mutations in the factor VIII gene. Br J Haematol. 2003 Sep;122(5):810-7. (
  • Bogdanova N, Markoff A, Eisert R, Wermes C, Pollmann H, Todorova A, Chlystun M, Nowak-Göttl U, Horst J. Spectrum of molecular defects and mutation detection rate in patients with mild and moderate hemophilia A. Hum Mutat. 2007 Jan;28(1):54-60. (
  • Bogdanova N, Markoff A, Pollmann H, Nowak-Göttl U, Eisert R, Wermes C, Todorova A, Eigel A, Dworniczak B, Horst J. Spectrum of molecular defects and mutation detection rate in patients with severe hemophilia A. Hum Mutat. 2005 Sep;26(3):249-54. (
  • Bolton-Maggs PH, Pasi KJ. Haemophilias A and B. Lancet. 2003 May 24;361(9371):1801-9. Review. (
  • Bowen DJ. Haemophilia A and haemophilia B: molecular insights. Mol Pathol. 2002 Apr;55(2):127-44. Review. Erratum in: Mol Pathol 2002 Jun;55(3):208. (
  • Graw J, Brackmann HH, Oldenburg J, Schneppenheim R, Spannagl M, Schwaab R. Haemophilia A: from mutation analysis to new therapies. Nat Rev Genet. 2005 Jun;6(6):488-501. Review. (
  • NCBI Gene (
  • Oldenburg J, El-Maarri O. New insight into the molecular basis of hemophilia A. Int J Hematol. 2006 Feb;83(2):96-102. Review. (
  • Shen BW, Spiegel PC, Chang CH, Huh JW, Lee JS, Kim J, Kim YH, Stoddard BL. The tertiary structure and domain organization of coagulation factor VIII. Blood. 2008 Feb 1;111(3):1240-7. Epub 2007 Oct 26. (
  • Thompson AR. Structure and function of the factor VIII gene and protein. Semin Thromb Hemost. 2003 Feb;29(1):11-22. Review. (


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.

Reviewed: May 2010
Published: February 8, 2016