PMM2 and congenital isolated hyperinsulinism: At least 15 CHI-related pathogenic genes have been identified to date (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF1A, HNF4A, HK1, PGM1, PMM2, FOXA2, CACNA1D, and EIF2S3) that are associated with 14 known genetic subtypes of CHI [1].