INS and diabetes mellitus: In this cohort, two patients (case 1, 2) tested negative for a panel of diabetes-related autoantibodies, which included islet cell antibodies (ICA), anti-glutamic acid decarboxylase antibodies (anti-GAD or GADA), insulin autoantibodies (IAA), tyrosine phosphatase-like protein antibodies (IA-2A), and zinc transporter 8 antibodies (ZnT8Ab).