Classic hemophilia A in a female

A 53-year-old woman with a history of recurrent bleeding complications since childhood and a positive family bleeding history, previously diagnosed as von Willebrand's disease, was investigated. She was found to have a markedly reduced level of antihemophilic factor (AHF) activity, a low AHF activity/AHF antigen ratio, normal Ristocetin-induced platelet aggregation and a normal level of von Willebrand factor activity. These findings were consistent with the diagnosis of classic hemophilia A which was confirmed by the results of similar studies in nine of the patient's relatives. The report illustrates the usefulness of newer laboratory methods in the differentiation between classic hemophilia A and von Willebrand's disease which may have important clinical implications.