In fact, the clinical symptoms of T1DM are preceded by a long period of “pre-diabetes”, characterized by specific histological features (autoimmune insulitis) and the presence of serum islet autoantibodies, including anti-insulin antibodies (IAAs), antibodies against insulin-producing islet cells (ICAs) and/or antibodies to glutamic acid decarboxylase (GAD65), antibodies to insulinoma-associated antigen-2 (anti-IA2), and antibodies to zinc transporter 8 (ZnT8), although patients remain normoglycemic and asymptomatic (stage 1). This evidence concerns the gene INS and type 1 diabetes mellitus.