Haemophilia is a lifelong disorder in which one of the essential clotting factors in the blood is lacking. This can cause a wide range of bleeding episodes, usually into the joints or muscles resulting in pain and swelling. Over a period of time bleeding into joints and muscles can cause permanent damage such as arthritis, chronic pain and joint damage which would require surgery to treat.

Bleeds can occur spontaneously, or as a result of trauma or injury such as a fall or knock. Bleeds are treated through an infusion of the clotting factor by injection. Haemophilia is an inherited condition, however in one out of three cases it appears in families with no previous history of the disorder.

The two most common types of Haemophilia are: Haemophilia A, or Classical Haemophilia - caused by a deficiency of Factor VIII; and Haemophilia B (sometimes called Christmas disease) caused by a deficiency of Factor IX.  There is little difference in clinical outcomes between the two types of Haemophilia but they require treatment with different clotting factors.  Haemophilia B is less common than Haemophilia A.