Neonatal hyperinsulinism with an ABCC8 mutation: A case report

BACKGROUND: Neonatal hyperinsulinism can result from perinatal stress, genetic disorders, or syndromes, which can lead to persistent or intractable hypoglycemia in newborns. Mutations in the ABCC8 gene result in abnormal functioning of potassium channel proteins in pancreatic β-cells, leading to an overproduction of insulin and congenital hyperinsulinemia. CASE SUMMARY: We report a case of a high-birth-weight infant with postnatal hypoglycemia and hyperinsulinemia, whose mother had pregestational diabetes mellitus with poor glycemic control and whose sister had a similar history at birth. Whole-exome sequencing revealed a new mutation in the ABCC8 gene in exon 8 (c.1257T>G), which also occurred in his sister and mother; thus, the patient was diagnosed with neonatal hyperinsulinism with an ABCC8 mutation. With oral diazoxide treatment, the child’s blood glucose returned to normal, and the pediatrician gradually discontinued treatment because of the child’s good growth and development. CONCLUSION: We report a new mutation locus in the ABCC8 gene. This mutation locus warrants attention for genetic disorders and long-term prognoses of hypoglycemic children.