The molecular basis of persistent hyperinsulinemic hypoglycemia of infancy and its pathologic substrates.

Recent advances in molecular genetics have established a molecular basis for persistent hyperinsulinemic hypoglycemia of infancy (PHHI) and resulted in the identification of a number of well-defined genetic defects. On the basis of the available information on the molecular changes so far described, an attempt has been made to classify PHHI patients according to their genotype and phenotype, with reference to molecular genetics, pancreatic pathology and clinical appearance. This classification has resulted in the differentiation of three groups of PHHI patients, two with diffuse beta cell hyperfunction and one with focal beta cell hyperfunction.