What is haemophilia?

Haemophilia is an inherited bleeding disorder. Blood contains many proteins, called clotting factors, which work to stop bleeding. People with haemophilia have a low level or absence of one of these clotting factors in their blood.

The lack of clotting factor causes people with haemophilia to bleed for longer periods of time than people whose blood factor levels are normal. People with haemophilia do not bleed faster than other people, and will not bleed to death from a minor cut or injury. The main problem for people with haemophilia is bleeding internally, mainly into muscles and joints.

What is the difference between haemophilia A and haemophilia B?There are two types of haemophilia: haemophilia A (sometimes called classical haemophilia) and hemophilia B (sometimes called Christmas disease). Both are caused by a low level or absence of one of the proteins in the blood (called factors) that control bleeding. Haemophilia A is caused by a deficiency of factor VIII, and haemophilia B is caused by a deficiency of factor IX.

There is no difference between the two types of haemophilia, except that haemophilia B is about five times less common than haemophilia A.


Are there other types of bleeding disorders?
Yes, there are several other factor deficiencies that also cause abnormal bleeding. These include deficiencies in factors I, II, V, VII, X, XI, XIII and von Willebrand factor. The most severe forms of these deficiencies are even rarer than haemophilia A and B.