GK and congenital isolated hyperinsulinism: We hypothesize that hepatic overexpression of a mutated form of GK, GKA456V, described in a patient with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) and could provide a model to study the consequences of GK-GKRP deregulation in vivo.GKA456V was overexpressed in the liver of streptozotocin diabetic mice.