Prematurity, macrosomia, hyperinsulinaemic hypoglycaemia and a dominant ABCC8 gene mutation
- 1Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- 2The Institute of Child Health, University College London, London, UK
- 3Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
- Correspondence to Dr Khalid Hussain,
Congenital hyperinsulinism (CHI) is a rare cause of hyperinsulinaemic hypoglycaemia (HH) and is due to an inappropriate secretion of insulin by the pancreatic β-cells. Genetic defects in key genes lead to dysregulated insulin secretion and consequent hypoglycaemia. Mutations in the genes ABCC8/KCNJ11, encoding SUR1/Kir6.2 components of the KATP channels, respectively, are the commonest cause of CHI. A 33+6 week gestation male infant weighing 3.38 kg (above 90th centile) presented with severe neonatal symptomatic hypoglycaemia. He required a glucose infusion rate of 20 mg/kg/min to maintain normoglycaemia (blood glucose levels at >3.5 mmol/l). Investigations established the diagnosis of HH (blood glucose 2.2 mmol/l with simultaneous insulin of 97.4 mU/l). Subsequent molecular genetic studies identified a heterozygous pathogenic ABCC8 missense mutation, p.R1353H (c.4058G>A), inherited from an unaffected mother. His HH was diazoxide responsive and resolved within 3 months of life.