HNF1A and congenital isolated hyperinsulinism: To date, ten genes have been linked to isolated CHI, explaining 45–55% of the cases (ABCC8, KCNJ11, GLUD1, GCK, HADH, HNF1A, HNF4A, SLC16A1, UCP2, HK1) and more than 28 genes or chromosomal abnormalities have been reported for syndromic CHI.