GAD2 and type 1 diabetes mellitus: Several autoantigens have been attributed to T1DM including insulin, glutamic acid decarboxylase 65-kDa (GAD65), islet antigen 2 (IA-2) [37], zinc transporter 8 (ZnT8), non-specific islet cell antibodies (ICAs), islet mitochondrial autoantigen imogen-38, pancreatic duodenal homeobox factor 1 (PDX1), chromogranin A (CHGA), islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), heat shock protein 60 (hsp60), and islet cell antigen 69 (ICA69) [38].