Diagnosis and treatment of hemophilia.

Hemophilia A and B are inherited bleeding disorders characterized by deficiency or dysfunction of coagulation protein factors VIII and IX, respectively. Recurrent joint and muscle bleeds are the major clinical manifestations. Replacement therapy with clotting factors, either at the time of bleeding or as part of a prophylactic regimen, is adapted to individual patient needs. The major complication of therapy is the development of neutralizing antibodies. In response, researchers have developed novel agents to both reduce the treatment burden and prevent bleeding regardless of the presence of inhibitors. Another new development, gene therapy, has the potential for a definitive cure. This review summarizes the pathophysiology, clinical presentation, diagnosis, and treatment of hemophilia, as well as information regarding neutralizing antibodies, immune tolerance induction, novel agents, and gene therapy.