Hemophilia

**Semantic type:** Disease or Syndrome

**Definition:** A deficiency or abnormality of a blood coagulation factor characterized by the tendency to hemorrhage. Hemophilia is typically a hereditary disorder but, rarely, may be acquired. Inherited coagulation factor-deficient hemophilias include hemophilia A or classic hemophilia (hereditary factor VIII deficiency) hemophilia B or Christmas disease (hereditary factor IX deficiency), and hemophilia C (hereditary factor XI deficiency). Factor VIII inhibitors may occur spontaneously as autoantibodies, resulting in acquired hemophilia known as acquired factor VIII deficiency. Approximately 10% of patients with acquired hemophilia have an underlying malignancy.

**Synonyms:** - Hemophiliac - hemophilia