Causes of haemophilia

It is caused by a lack of clotting factors:

* Haemophilia A involves a lack of the clotting Factor VIII. (This represents 90% of haemophilia cases.[citation needed])
* Haemophilia B involves a lack of the clotting Factor IX.
* Haemophilia C involves a lack of the clotting Factor XI.
* Hypofibrinogenemia involves a lack of the clotting factor Factor I. Because it is so rare, about 1 or 2 cases per million births, it has no definite treatment approved by the FDA. It affects males and females equally. The blood of people with Hypofibrinogenemia neither clots nor contains sufficient amounts of Fibrinogen.