Mutations in the Kir6.2 (KCNJ11 gene, omim #600937) and SUR1 (ABCC8 gene, omim #600509) subunits lead to permanent closure of the channel and account for 40–45% of all cases of congenital hyperinsulinism [36]. The gene discussed is KCNJ11; the disease is hyperinsulinism.