INS and type 2 diabetes mellitus: Moreover, if we consider that the majority of type 2 diabetic patients who are truly lean have positive islet cell antibodies and/or insulin autoantibodies belonging, therefore, to the LADA group of patients [96], the remaining bona fide type 2 diabetic patients with BMI < 25 and normal body composition with no secondary etiologies (pancreatopathies, endocrinopathies, etc.)represents a tiny portion that need further investigations.