Permanent Neonatal Diabetes Mellitus in an Indian Infant Due to a Novel Mutation in the Glucokinase Gene

Abstract

Background: Neonatal diabetes mellitus (NDM) is a rare condition, usually genetic in etiology, that presents with hyperglycemia requiring insulin within the first 6 months of life. Most cases of permanent NDM are caused by mutations in the KCNJ11 or ABCC8 gene, which are involved in the potassium adenosine triphosphate channels. Clinical Description: A 1.88 kg female infant product of a consanguineous marriage was delivered at term by cesarean section for oligohydramnios and intrauterine growth retardation. There was a strong family history of DM involving the mother, father, and grandparents. Clinical examination was normal. Routine blood sugar monitoring identified hyperglycemia at 1 and 3 h. There was no clinical or laboratory evidence of sepsis. Management: Persistent hyperglycemia continued that necessitated the administration of insulin from the 1st day onward. The abdominal ultrasonogram was normal. C-peptide was low, indicating poor endogenous insulin production. Genetic analysis revealed a novel mutation in the glucokinase (GCK) gene (p. Glu178Asp). A brief trial of sulfonylureas (glibenclamide) was ineffective. The infant attained control, although with considerable difficulty, on a mixture of NPH and long-acting insulin. After 5 months of follow-up, she is thriving well. Conclusion: GCK mutation is a rare but important cause of NDM. To the best of our knowledge, this is the first Indian infant to be reported with a GCK gene mutation.