Based on the autoantibody profile, two types of AIH are recognized: type 1 (AIH-1), positive for ANA and/or anti-smooth muscle antibody (SMA), and occurring at any age, and type 2 (AIH-2), positive for anti-liver-kidney microsomal antibody (anti-LKM) or for anti-liver cytosol type-1 antibody (anti-LC-1), with a peak incidence in children and adolescents [17–19]. This evidence concerns the gene SMN1 and autoimmune hepatitis.