GAD2 and type 1 diabetes mellitus: Glutamic acid decarboxylase 65 (GAD65), a neuroendocrine enzyme, is a key autoantigen in type 1 diabetes (T1D) [1], in Latent Autoimmune Diabetes of Adults (LADA) [2] and in various neurological diseases [3], [4], [5], [6], [7].