Alternative names: Christmas disease; Factor IX Hemophilia

Hemophilia B is a hereditary blood coagulation disorder. It is caused by a deficiency of a blood plasma protein called factor IX that affects the clotting property of blood.

Hemophilia is a hereditary bleeding disorder of specific blood clotting factors. There are several types of Hemophilia, including Hemophilia A and B. Hemophilia A is 7 times more common than Hemophilia B.