In cases where islet antibodies were negative or not reported, we diagnosed them to have T1DM based on their presentation with diabetic ketoacidosis (DKA) in a previously normoglycemic patient, new onset severe hyperglycemia with a low C-peptide in a patient without known diabetes, new insulin requirement in a patient with known T2DM; and anyone with “fulminant” T1DM. This evidence concerns the gene INS and type 1 diabetes mellitus.