The main autoantigens that are recognized by T cells in T1D patients are insulin and its precursor preproinsulin (PPI) hereafter described as insulin, GAD65, ZnT8, IA2 and islet-glucose-6-phosphatase catalytic subunit-related protein (IGRP) (49, 50). This evidence concerns the gene GAD2 and type 1 diabetes mellitus.