Biomarkers for T1D are autoantibodies (Ab) to islet cell antigens (ICA), tyrosine phosphatase (IA2), glutamic acid decarboxylase-65 (GAD), insulin (IAA), and zinc transporter ZnT8Solute carrier family 30 member 8 (SLC30A8). Here, GAD1 is linked to type 1 diabetes mellitus.