AIH diagnosis is typically suspected after ruling out other causes of hepatitis (such as vial hepatitis, hemochromatosis, Wilson's disease, and primary biliary cirrhosis) through serological tests and by findings of high titers of certain autoantibodies (ANA and anti-SMA for type 1 AIH and anti-LKM-1 for type 2 AIH). Here, BTG3 is linked to hepatitis A virus infection.