What Is Hemophilia
Hemophilia is primarily an inherited disease that prevents the blood from clotting properly.1,2 Approximately 18,000 individuals in the United States have hemophilia.3 People with hemophilia have a deficiency of a blood protein, also called a "clotting factor," that is necessary to clot the blood and stop bleeding.3 Originally, hemophilia was thought to be a single disease. In the 1950s, it was recognized that there were 2 forms of the disease: hemophilia A and hemophilia B.4
Hemophilia A
Hemophilia A is the most common form of hemophilia. People with hemophilia A, also called "classic hemophilia," have a deficiency in clotting factor VIII. The clotting factor is either missing or is present at a low level.3
Hemophilia A occurs across all populations in the world.1 Hemophilia A is found almost exclusively in males, occurring in about 1 in every 10,000 males.3,4
Hemophilia B
People with hemophilia B have a deficiency in coagulation factor IX. Hemophilia B is also called Christmas disease, named for the first person diagnosed with a factor IX deficiency.5 It is the second most common form of hemophilia, occurring in about 1 in 60,000 people.4 Like hemophilia A, hemophilia B is found almost exclusively in males.
Signs And Symptoms
The signs and symptoms of hemophilia A and hemophilia B are similar. They can include:
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Bleeding following injury or surgery2 |
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Spontaneous bleeding (spontaneous means that the bleeding occurs without an apparent cause)2 |
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Bruising6 |
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Pain and swelling resulting from bleeding into joints and muscles6 |
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Blood in the urine or stool6 |
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Heavy bleeding following circumcision6 |
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Unexplained nosebleeds6 |
Classification
Hemophilia is classified as mild, moderate, or severe, depending on the amount of clotting factor in the blood. Severe hemophilia is usually diagnosed during infancy; a mild form may not be diagnosed until adulthood.7
