Mild Congenital Hyperinsulinism Caused by Mutation in Human Glucokinase Gene

Congenital hyperinsulinism (CHI) is a rare hereditary disease characterized by the development of hypoglycemia in both infants and adult patients. CHI may be induced by activating mutations in the glucokinase (GCK) gene, which encodes the human glucokinase enzyme. This form of the disease is characterized by considerable phenotypic heterogeneity and may vary in severity of its course. We present a familial case report of mild CHI caused by a novel variant, c.212T>C (p.Val71Ala), in the GCK gene in a 41-year-old mother and a 15-year-old daughter. The clinical picture of hypoglycemia in the patients was not pronounced, which makes this clinical case remarkable. Moreover, a variant of uncertain clinical significance, c.1903G>A (p.Ala635Thr), in the ABCC8 gene was detected, which may also have contributed to the course of the disease in these patients.