Types of Haemophilia

Haemophilia A and Haemophilia B

There are two main types of haemophilia - Haemophilia A (due to factor VIII deficiency) and Haemophilia B (due to factor IX deficiency). They are clinically almost identical and are associated with spontaneous bleeding into joints and muscles and internal or external bleeding after injury or surgery.

After repeated bleeding episodes permanent damage may be caused to the joints and muscles that have been affected, particularly the ankles, knees and elbows.

Approximately 1 in 5,000 males is born with Haemophilia A, and 1 in 30,000 males is born with Haemophilia B. Haemophilia affects people of all races and ethnic origins globally. The conditions are both X-linked and virtually all sufferers of Haemophilia are males. Female carriers may also bleed abnormally, because some have low levels of the relevant clotting factor.

People with Haemophilia have a genetic mutation in the affected gene on the X chromosome, which results in reduced production of Factor VIII or IX and creates a bleeding tendency, because coagulation takes much longer than normal, thus making the clot weak and unstable.

Approximately one third of patients with haemophilia have no family history of the disease, either because of new genetic mutations, or because previous affected generations either had daughters (who were carriers) or sons who died in early childhood from haemophilia or any other cause or who were not affected.


Acquired haemophilia

This is very rare. The patient develops the condition during his/her lifetime and it does not have a genetic or heritable cause. It occurs when the body forms antibodies that attack one or more blood clotting factors, (usually factor VIII), thus preventing the blood clotting mechanism from working properly. Patients may be male or female and the pattern of bleeding is rather different from that of classical haemophilia, the joints being rarely affected. The disorder is particularly associated with old age and occasionally complicates pregnancy.