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Hemophilia A

It is possible that the main title of the report Hemophilia A is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • classical hemophilia
  • factor VIII deficiency
  • haemophilia A

Disorder Subdivisions

  • None

General Discussion

Hemophilia A, also known as classical hemophilia, is a genetic bleeding disorder caused by insufficient levels of a blood protein called factor VIII. Factor VIII is a clotting factor. Clotting factors are specialized proteins that are essential for proper clotting, the process by which blood clumps together to plug the site of a wound to stop bleeding. Individuals with hemophilia A do not bleed faster or more profusely than healthy individuals, but, because their blood clots poorly, they have difficulty stopping the flow of blood from a wound. This may be referred to as prolonged bleeding or a prolonged bleeding episode. Hemophilia A can be mild, moderate or severe, depending on the baseline level of factor VIII made by that individual. In mild cases, prolonged bleeding episodes may only occur after surgery, dental procedures or trauma. In more severely affected individuals, symptoms may include prolonged bleeding from minor wounds, painful swollen bruises, and unexplained (spontaneous) bleeding into vital organs as well as joints and muscles (internal bleeding). Hemophilia A is caused by disruptions or changes (mutations) to the F8 gene on the X chromosome. This mutation may be inherited or occur randomly with no previous family history of the disorder (spontaneously). Hemophilia A is fully expressed in males only, although some females who carry the gene may have mild or, rarely, severe symptoms of bleeding. Although there is no cure for hemophilia, effective therapies have been developed; most affected individuals can lead full, productive lives by maintaining proper treatment and care.

Hemophilia is a general term for a group of rare bleeding disorders caused by congenital deficiency of certain clotting factors. The main form of hemophilia is hemophilia A. In rare cases, hemophilia A can be acquired during life (acquired hemophilia A). Although both disorders involve deficiency of the same clotting factor, the bleeding pattern is quite different. The reason the bleeding patterns differ between these disorders is not fully understood. This report only deals with the genetic form of hemophilia A.


National Hemophilia Foundation
116 West 32nd Street, 11th Floor
New York, NY 10001
Tel: (212)328-3700
Fax: (212)328-3777
Tel: (800)424-2634

Canadian Hemophilia Society
400-1255 University Street
Quebec, H3B 3B6
Tel: 5148480503
Fax: 5148489661
Tel: 8006682686

NIH/National Heart, Lung and Blood Institute
P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

World Federation of Hemophilia
1425 René Lévesque Blvd. W. Suite 1010
Quebec, H3G 1T7
Tel: 5148757944
Fax: 5148758916

Hemophilia Federation of America
210 7th St. SE
Suite 200B
Washington, DC 20003
Tel: (202)675-6984
Fax: (202)675-6983
Tel: (800)230-9797

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Madisons Foundation
PO Box 241956
Los Angeles, CA 90024
Tel: (310)264-0826
Fax: (310)264-4766

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 8/9/2012
Copyright 1985, 1986, 1990, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2004, 2007, 2012 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: 8/, 015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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