Inactivating mutations in the ABCC8 and KCNJ11 genes, encoding the SUR1 and Kir6.2 subunits of the pancreatic ATP-sensitive potassium (KATP) channel are responsible for 80-84% of confirmed monogenic cases of CHI 5,6. This evidence concerns the gene KCNJ11 and congenital isolated hyperinsulinism.