Acquired hemophilia A (AHA) is a bleeding disorder characterized by the formation of autoantibodies against endogenous coagulation factor VIII (FVIII) in an acquired manner, resulting in a marked decrease of FVIII activity and presenting with bleeding episodes such as spontaneous subcutaneous hemorrhage, intramuscular hemorrhage and occasional occurrence of serious hemorrhages. The prognosis of AHA is poor, and mortality of early onset AHA is high. The gene discussed is F8; the disease is hemorrhagic disease.