Mutations in at least ten genes have been identified to cause CHI (ABCC8, KCNJ11, GLUD1, GCK, HADH1, UCP2, HNF4A, HNF1A, SLC16A1, PHOX2B), most commonly in ABCC8 or KCNJ11 expressing the two subunits of the pancreatic β-cell KATP-channel, the sulfonylurea receptor 1, and the potassium inward rectifier 6.2 (Kir6.2) (7–11). This evidence concerns the gene ABCC8 and congenital isolated hyperinsulinism.