Islet‐targeting autoantibodies directed against insulin, 65 kDa glutamic acid decarboxylase (GAD65) [2], insulinoma‐associated protein 2 (INSM2) [3], and zinc transporter 8 (ZnT8)—proteins associated with secretory granules in β‐cells—serve as biomarkers for T1DM‐related autoimmunity. This evidence concerns the gene GAD2 and type 1 diabetes mellitus.