Haemophilia is a genetically inherited bleeding disorder where there is a deficiency of a clotting factor in the blood. This results in a form of bleeding tendency. Thus, the haemophilia patient often suffers from easy bruising and bleeding into muscles and joints. Because of the genetic pattern of inheritance, the disorder generally affects males only. Females with the haemophilia genes are known as carriers.
There are 2 types of haemophilia.
- Haemophilia A â€“ Deficiency of clotting factor 8 (VIII)
- Haemophilia B â€“ Deficiency of clotting factor 9 (IX)
There is another hereditary bleeding disorder known as von Willebrandâ€™s disease (vWD). A patient with vWD has a diminished production of the von Willebrand clotting factor. In contrast with haemophilia, vWD affects both males and females equally. They usually bleed from the nose, mouth or intestinal tract.
The incidence of haemophilia A is 1 in 10,000 males.
The incidence of haemophilia B is 1 in 50,000 males.
There is no known geographical variation in the incidence of haemophilia.
In the world, 350,000 people are estimated to be with severe or moderate haemophilia A. In Singapore, about 200 people are patients of haemophilia A and B.
The severity of the bleeding tendency depends on the range of activity of factor 8 or 9.
|Normal Person||50 â€“ 200%||0.5 â€“ 2 IU|
|Carrier||25 â€“ 49%||0.25 â€“ 0.49 IU|
|Haemophiliac||Mild||6 â€“25%||0.06 â€“ 0.25 IU|
|Moderate||1 â€“ 5%||0.01 â€“ 0.05 IU|
|Severe||< 1%||< 0.01 IU|