Haemophilia: what is it?
Haemophilia is a bleeding disorder in which one of the essential clotting factors is deficient and is hereditary in most cases.
Haemophilia A is also known as Classical Haemophilia. It is the most common form of haemophilia and is caused by the deficiency of Factor VIII. This means that the body does not make enough Factor VIII.
Haemophilia B is also known as Christmas Disease. It is due to the deficiency of Factor IX. This means that the body does not make enough Factor IX.
It affects males almost exclusively, and is passed on through females who carry the defective genes. Although many female carriers appear to be unaffected, some have reduced Factor VIII levels and this is associated with a mild bleeding disorder. However, between one quarter to one third of all occurrences appear in families with no previous history.
There is no cure for haemophilia. It is a life-long condition. The development of clotting factor concentrates has meant that it can be managed effectively.
People with haemophilia suffer differing degrees of severity of their disorder. The clinical severity of haemophilia is related to the level of deficiency of the clotting factor.
Bleeding is mostly internal. The deficiency in clotting factors is associated with a wide range of bleeding episodes, usually into the joints or muscles. These bleeding episodes, or 'bleeds', may occur spontaneously (apparently without any cause), or as a result of trauma (injury). Bleeding can be stopped by infusion of the appropriate clotting factor by intravenous injection. If internal bleeding is not quickly stopped with treatment, it will result in pain, swelling and damage to the tissues. Over a period of time, bleeding into joints and muscles causes permanent damage (such as arthritis in the joints) and chronic pain.
Clinical severity within an individual may vary with time. Severity also varies between individuals with the same level of coagulation factor.
Last Reviewed: 24 May 2007
