Encyclopedia / H / Hemophilia



Hemophilia is one of several disorders of the blood clotting process that greatly prolong coagulation (clotting) time.


Coagulation, or clotting, is the body's mechanism to halt bleeding. It involves at least 14 sequential steps, each requiring a specific plasma protein or "factor" normally found in the blood. In hemophilia, one of the factors required for the clotting sequence is deficient or absent. The condition known as hemophilia has been recognized for thousands of years.

The two most common forms of hemophilia are hemophilia A and hemophilia B. Hemophilia A and B have similar symptoms and were not recognized as separate disorders until 1952.

Hemophilia A (classic hemophilia), is caused by the deficiency of Factor VIII.

Hemophilia B (also called Christmas disease, for the name of the family the disorder was first observed in), is caused by the deficiency of factor IX.

Hemophilia A is four times as common, with an estimated incidence of 1 in 10,000 males, while hemophilia B is estimated to occur in one in 40,000 males. Approximately 1 woman in 5,000 is a carrier for hemophilia A, and 1 in 20,000 is a carrier of hemophilia B.

Hemophilia is typically divided into three classes: severe, moderate and mild, based on the level of clotting factor in the blood. In severe hemophilia, there is less than 1 percent of normal clotting factor. The degree of severity tends to be consistent from generation to generation.

Contrary to popular belief, minor cuts and wounds do not usually present a threat to hemophiliacs. Rather, the greatest danger comes from spontaneous bleeding that may occur in joints and muscles. This is most prone to occur during years of rapid growth, typically between the ages of 5 and 15 years.

Repeated spontaneous bleeding in joints may cause arthritis, and adjacent muscles become weakened. Pressure on nerves caused by the accumulation of blood may result in pain, numbness, and temporary inability to move the affected area. In the past, this led to permanent crippling disability by adulthood.

The development of purified clotting factors in the 1970s, isolated from donated blood, significantly improved the long-term outlook for hemophiliacs. Severe hemophiliacs require transfusions of clotting factors as frequently as once a week.


Both hemophilia A and B are X-linked recessive genetic diseases. While females carry the trait, they very rarely exhibit any symptoms of the disorder.


Patients with hemophilia may present with bleeding anywhere, but most commonly into joints (knees, ankles, elbows), into muscles, and from the digestive tract. Those with severe hemophilia may bleed spontaneously.


Blood tests to determine the effectiveness of clotting and the levels of clotting factors will be abnormal.


Early prophylactic use of clotting factors with severe hemophilia is gaining acceptance as a way to prevent pain and morbidity associated with bleeding disorders. Treatment of severe hemophilia A or B consists of administration of plasma-derived or recombinant clotting factor concentrates.

The plasma-derived concentrates have saved lives and prevented disability. However, their use in the past has been complicated by infection with viral pathogens particularly the human immunodeficiency virus and the hepatitis viruses. Monoclonal antibody purification techniques, heat inactivation, and virucidal detergent treatments have rendered plasma-derived concentrates relatively safe. Recombinant DNA technology has provided a series of synthetic products.

A genetically engineered clotting factor to treat people with hemophilia has been licensed by the FDA. The product, antihemophilic factor (recombinant) is used for preventing and controlling excessive bleeding and for preparing people with hemophilia A for surgery. The brand name is Kogenate. Kogenate is the second recombinant DNA-derived clotting factor for people with hemophilia A. The first product, Recombinate, was licensed in late 1992.

Previously, patients were given factor VIII concentrates pooled from thousands of plasma donations. Kogenate is made using baby hamster kidney cells that have been altered by recombinant DNA technology to produce factor VIII. The resulting factor is highly purified, eliminating any possibility of transmission of virus from plasma.

Hemophilia B is managed with factor IX concentrates. Factor VIII concentrates are ineffectual in this type of hemophilia. The use of Factor IX concentrate are to maintain a patient through a major surgical procedure. Factor levels should be measured to ensure that expected levels are achieved and that an inhibitor is nor present. Factor IX concentrates contain a number of other proteins, including activated coagulating factors that appear to contribute to a risk of thrombosis with recurrent usage of Factor IX concentrates. Because of the risk of thrombosis, more care is needed in deciding to use these concentrates.


What form of hemophilia is it?

Can hemophilia-like symptoms develop in middle age?

Are there any severe side effects of the recombinants?

What is the risk of HIV or other infection with hemophilia treatment?

What limitations may exist for activities such as school, work, etc.?