Monogenic and dominant glucokinase variants (Online Mendelian Inheritance in Man, OMIM *138079 (accessed on 28 October 2023) have been observed in several diseases, including maturity-onset diabetes of the young type 2 (MODY2 OMIM#138079 [2,3,4,5,6,7,8,9]), permanent neonatal diabetes mellitus (PNDM, OMIM#606176), and persistent hyperinsulinemic hypoglycemia in infancy (PHHI, OMIM #256450, #601820, #602485, #609975, #609968, #606762, #610021 [10,11,12,13,14]). Here, GCK is linked to maturity-onset diabetes of the young type 2.