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What is hemophilia?
Hemophilia is a hereditary disorder in which one of the proteins that causes blood to clot is missing, reduced or does not function adequately, which leads to a delay or disruption in blood clotting and results in prolonged bleeding.

Types of hemophilia
The two most common types of hemophilia are Factor VIII and Factor IX Deficiency. Factor VIII Deficiency also is called classic hemophilia or hemophilia A. Factor IX Deficiency is often known as Christmas disease or hemophilia B. Hemophilia occurs in about one of every 5,000 males born in the United States. About 80 percent of persons with hemophilia have Factor VIII Deficiency. Blood tests are needed to tell the difference in types of hemophilia as the bleeding patterns, signs and symptoms are identical. However, the type of treatment to stop bleeding depends upon the type of hemophilia.

Causes of hemophilia

The first two steps in clotting work normally for persons with hemophilia. However, persons with hemophilia do not have enough of one of the clotting factors needed to make fibrin strands. Without the fibrin strands, a firm clot does not form. Bleeding will only temporarily stop since the clot easily dissolves.

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Genetics of hemophilia

The gene that causes hemophilia is carried on the X chromosome (one in the pair of chromosomes that determines sex). The hemophilia gene is therefore called "sex-linked." The hemophilia gene also is "recessive," which means that if the other chromosome in the pair is normal X chromosome, the normal chromosome "dominates" over the recessive, hiding this trait. Therefore, since females have two X chromosomes, they would have to have two hemophilic X chromosomes to have the disease. Males, on the other hand, have only one X chromosome. If a male’s X chromosome has the abnormal factor gene, he will automatically have hemophilia.

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Severity and symptoms

Persons with hemophilia do not bleed any faster than persons without a bleeding disorder. Generally external bleeding (cuts, scrapes) does not cause any problems. In children, bleeding is closely related to the stages of development and to physical activity. For babies and toddlers, the most common sites of bleeding are the mouth and head. Older children and adults often have bleeding into joints and muscles, especially the knees, ankles and elbows. While the most common bleeding in hemophilia is not life threatening, bleeding in a few places of the body is very dangerous. Examples of life-threatening bleeds are bleeds into the head, neck, spinal cord or stomach/intestines.

How is the severity of hemophilia determined?

The table below shows the relationship of mild, moderate and severe hemophilia to the amount of clotting factors VIII or IX.


Levels of Severity


Factor VIII or IX level


What to expect

Less than 1%

Severe hemophilia

Bleeding after minor injury; may bleed "spontaneously" (without known injury)

1 – 5%

Moderate hemophilia

Bleeding after minor injury is possible; may have spontaneous bleeding

5 – 30%

Mild hemophilia

Usually prolonged bleeding only after minor trauma or surgery

50 – 150%


No abnormal bleeding

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There is no cure for hemophilia at this time. The current treatment is to replace the missing clotting factor in the blood by injecting intravenously (into a vein) products containing concentrated amounts of the missing clotting factor. Clotting factor is now given "prophylactically" to prevent bleeding.

Can hemophilia ever be cured?

Several centers throughout the country currently are working on research to modify genes in humans to allow them to make clotting factors. This work is very promising. The CVCCD is part of a national network of treatment centers so our patients often have access to new clinical trials.

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VCU Health System | Central Virginia Center for Coagulation Disorders
P.O. Box 980461 | Richmond, VA | 23298-0461
phone: (804) 827-3306 | toll free: (866) 288-2516 | fax: (804) 692-0291

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last updated: 02/17/2014
Central Virginia Center for Coagulation Disorders