What is haemophilia?

Haemophilia is a blood clotting disorder where there is not enough clotting factor VIII (8) or IX (9) in the blood. A clotting factor is a protein in the blood that helps control bleeding. It is incurable and without proper treatment, can be life threatening.

Haemophilia is an inherited condition and occurs in families. However in 1/3 of cases it appears in families with no previous history of the disorder. The genetic alteration causing haemophilia is passed down from parent to child through generations. Men with haemophilia will pass the gene on to their daughters but not their sons. Women who carry the altered gene can pass the gene on to their sons and daughters. Sons with the gene will have haemophilia. Some women and girls who carry the gene may also experience bleeding problems.

There are different types of haemophilia. Each 'type' refers to the lack of a specific clotting factor. Factors VIII and IX are the most common deficiencies, however others do exist. Factor VIII deficiency is known as haemophilia A, while haemophilia B refers to deficiency of Factor IX.

Depending on the degree of the deficiency. (ie how much factor is missing), it can be:

• Mild Haemophilia - 5-40% factor VIII or IX activity
• Moderate Haemophilia - 1-5% factor VIII or IX activity
• Severe Haemophilia - Less than 1% factor VIII or IX activity