For the patient with adult-onset diabetes, three features, aside from demographics, have provided traction in dissecting the nature of this disease process: genetics, including genetic risk scores (GRS); immunology, in the form of diabetes autoantibodies, including autoantibodies to GAD65 (GADA), and serum C-peptide as a proxy for insulin secretion (Fig. 1) [2, 3]. This evidence concerns the gene INS and type 2 diabetes mellitus.