Kabuki Syndrome Presenting with Congenital Hyperinsulinemic Hypoglycemia: The First Neonatal Case Reports in Korea

Kabuki syndrome (KS) is a rare congenital disorder characterized by distinctive craniofacial features, skeletal anomalies, dermatoglyphic variations, intellectual disability, and postnatal growth restriction.Pathogenic variants in KMT2D and KDM6A are identified in approximately 80% of affected individuals.Although hypoglycemia has been regarded as an uncommon manifestation, emerging evidence suggests that hyperinsulinemic hypoglycemia (HH) may represent an underrecognized feature of KS, particularly in neonates before characteristic dysmorphic features become apparent.We describe two neonates with genetically confirmed KS who initially presented with HH, representing the first reported cases of this association in Korea.A KDM6A mutation was identified in Patient 1, and diazoxide treatment successfully maintained normoglycemia.Patient 2 carried a KMT2D mutation and demonstrated improvement following treatment with diazoxide and hydrocortisone, allowing discontinuation of therapy.Persistent HH during the neonatal period may serve as an early indicator of KS, prompting timely genetic testing.