GAD2 and type 1 diabetes mellitus: Currently, susceptibility genes, such as high-risk HLA genes and islet autoantibodies (GAD65, IA-2, pro-insulin, zinc transporter-8 (ZnT8), islet-specific glucose-6-phosphatase catalytic subunit related protein (IGRP), imogen-38, pancreatic duodenal homeobox factor 1 (PDX1), chromogranin A (CHGA) and islet amyloid polypeptide (IAPP)) are the gold-standard approaches for the detection of T1DM.