Hypoglycemia, symptomatic hypoglycemia, and severe hypoglycemia (SH, a circumstance where the patient can be unconscious, and requires the assistance of someone else), are frequent in persons with type 1 (T1D) and type 2 diabetes (T2D) who use insulin, or in T2D patients on sulphonylureas; frequency of hypoglycemia is greater in T1D than in T2D patients, and depends on regimens of insulin administration, on age and associated medical problems [1–3]. The gene discussed is INS; the disease is Hypoglycemia.