INSM2 and type 1 diabetes mellitus: Although still carried out, it has largely been superseded by individual tests for autoantibodies to the four major autoantigens in T1D: insulin (IAA) (37), glutamic acid decarboxylase (GADA) (38), insulinoma-associated protein 2 (IA-2A) (39), zinc transporter 8 (ZnT8A) (40).