GAD1 and diabetes mellitus: Results from investigations for diabetes mellitus showed a fasting c-peptide of 1.08 ng/mL (0.48–3.30 ng/mL), anti-islet cell antibodies (ab) negative, and glutamic acid decarboxylase (GAD) ab of 0.01 U/ml which suggested that a diagnosis of type 2 diabetes mellitus would be appropriate.