A major acute complication of diabetes is a defective response of glucagon, catecholamines and glucocorticoids to insulin-induced hypoglycemia coined “glucose blindness.” This occurs more frequently with antecedent hypoglycemia and hypoglycemia unawareness, and it is in part due to poor counterregulatory responses (Bolli et al., 1983; Dagogo-Jack et al., 1993; The Diabetes Control and Complications Trial Research Group, 1993; Fanelli et al., 1994). The gene discussed is GCG; the disease is diabetes mellitus.