Applying cut-off values based on the mean plus 3 standard deviations of the controls, GAD65, IA2, and IA2-β autoantibodies demonstrated 67% and 98.9% specificity, 77% sensitivity and 100% specificity, and 60% sensitivity and 100% specificity for the diagnosis of T1D, respectively. Here, GAD2 is linked to type 1 diabetes mellitus.