Hemophilia A is caused by a missing or dysfunctional clotting factor VIIl. Although hemophilia A is usually inherited, a spontaneous mutation of the person’s own genes is responsible for about 30% of cases.

Hemophilia A is diagnosed by measuring the factor VIII activity in the blood. Depending on the factor VIII activity measured, the severity of hemophilia A is categorized as mild, moderate or severe. About one-third of patients suffer from the most severe form of this disease. Patients with hemophilia A have prolonged bleeding after injuries, operations, and dental treatment. In severe cases, there may also be spontaneous bleeding, that is to say, bleeding for no obvious reason. Severe complications may arise from bleeding into the joints, muscles, brain or other internal organs. Mild cases of hemophilia A may remain undetected until the person has an operation or a serious accident. Treatment of hemophilia A is extremely effective.