Coagulation
is a complex process by which blood forms clots. Disorders of
coagulation can lead to an increased risk of bleeding (hemorrhage)
and/or clotting (thrombosis). Bleeding disorders can be acquired or
inherited.
The best known coagulation factor disorders are the hemophilias. The
three main forms are Hemophilia A (Factor VIII deficiency),
Hemophilia B (Factor IX deficiency or "Christmas disease") and
Hemophilia C (Factor XI deficiency). Together with Von Willebrand
disease, these conditions predispose to bleeding and bruising. Most
hemophilias are inherited and occur mainly in males, while Von
Willebrand disease can occur in both males and females.