KCNJ11 and hyperinsulinemic hypoglycemia: Inactivating or activating mutations in one of the two subunits forming this channel, i.e., the sulfonylurea receptor-1 gene (SUR1, ABCC8) or the inward rectifier K+ channel (Kir6.2, KCNJ11), cause congenital hyperinsulinemic hypoglycemia (Thomas et al. 1995) and diabetes in neonates and infants (Babenko et al. 2006).