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hemophilia

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Hemophilia is a genetic bleeding disorder. People who have hemophilia have a deficiency or an absence of a coagulation protein. A blood clotting factor is deficient or absent. Bleeding is most often into joints, such as the knee, elbow, or ankle, but bleeding can occur anywhere in the body. People with hemophilia bleed longer, not faster.

The severity of hemophilia varies greatly. Hemophilia A and Hemophilia B are the most common genetic bleeding disorders. Hemophilia A is observed in 80 percent of hemophiliacs and is a deficiency or absence of Factor VIII. It can also be referred to as "classic" hemophilia. In the second most common, hemophilia B, factor IX is missing.

This is also known as the "Christmas Disease" because of the surname of the first patient studied. Hemophilia was identified as early as biblical times. Doctors in medieval times were familiar with it as well. In 1803, a Philadelphia doctor published the first description of hemophilia in the United States. But it was not until 30 years later that hemophilia became widely recognized. Hemophilia later developed a reputation as the "royal disease" because it passed from Queen Victoria of England to her descendants throughout the royal houses of Europe.

About eighty percent of all cases of hemophilia have an identifiable family history of the disease; in other instances, it may be attributable to a spontaneous mutation. Researchers recently discovered that the spontaneous mutation of the factor VIII gene in two children was due to the attachment of a foreign "jumping gene" that disrupted the blood-clotting ability of the factor VIII gene. Inheritance is controlled by a recessive sex-linked factor carried by the mother on the X chromosome. A probability of one in two exists that each boy born to a normal male and a carrier female will be hemophiliac and the same chance that each girl of this union will be a carrier.

Of the children of a hemophiliac male and a normal female, all the girls will be carriers and all the boys will be normal. Males cannot transmit the disability, and female carriers are free of the disease. Conventional wisdom suggests that 1 in 10,000 males in the United States have hemophilia. However, increased research and focus, on bleeding disorders in general and on bleeding disorders in women specifically, suggest a shift in what...

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...h factor VIII replacement therapy is best for them. Inhibitors are proteins called antibodies that are made by our immune system to defend us from harmful disease. When our immune system identifies a foreign substance, it makes antibodies that will specifically recognize that substance and destroy it.

In some individuals with severe hemophilia, the factor VIII replacement therapy is identified as a foreign substance by their immune system. If this happens, their immune system will make antibodies against factor VIII. These antibodies will inhibit the ability of the factor to work in the clotting process. The higher the antibody or inhibitor level, the more factor VIII replacement therapy it takes to overcome the inhibition and produce clotting. This can complicate the treatment of a bleed. The good news is that there are different types of therapies available to successfully treat most individuals who develop inhibitors.

Work Cited Louis Levine, B.S., M.S.Ed., A.M., Ph.D. Professor, Department of Biology, City College of New York. "Hemophilia," Microsoft® Encarta® Online Encyclopedia 2000 http://encarta.msn.com © 1997-2000 Microsoft Corporation. All rights reserved.
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