AHA is a rare but potentially life-threatening bleeding disorder caused by autoantibodies that neutralize FVIII.1) The management of AHA, which involves immunosuppressive therapy to eradicate the FVIII inhibitor and hemostatic treatment using bypassing agents to control active bleeding, is well established.2–5) However, surgical intervention for patients with AHA remains challenging because of the high risk of perioperative hemorrhagic complications. The gene discussed is F8; the disease is hemorrhagic disease.