Background: Congenital hyperinsulinism is a frequent cause of persistent hypoglycaemia in neonates. Mutations of the KATP channel subunit are the most common molecular defects. We report here a novel ABCC8 gene mutation causing a severe form of CHI in a newborn.
Case report: A 10-day-old boy born to consanguineous parents was referred for persistent hypoglycaemia. He was born by normal vaginal delivery at 38 weeks gestation, birth weight was 4.46 kg, birth length 54.5 cm with severe perinatal asphyxia. Hypoglycaemia started early needing high dose of glucose infusion (>15 mg/kg/min) and investigations showed hyperinsulinimic hypoglycaemia with insulin levels of 22.9 μU/ml (2.710.30) and C peptide: 8.55 ng/ml (N: 1.104.40). Heart ultrasound revealed hypertrophic cardiomyopathy. Diazoxide was started and increased to 20 mg/kg/day, he then became unresponsive and was started on octreotide at 20 mc/kg/day. Genetic testing revealed a novel ABCC8 missense mutation, p.Asp861Tyr that has never been reported previously but predicted to be pathogenic. Our patient is homozygote for this mutation and both his parents are heterozygote, confirming the diagnosis of autosomal recessive congenital hyperinsulinism. Now aged 5 years, the patient shows good glycaemic control on octreotide in combination with frequent feeding. However, he has developmental delay with epilepsy, requiring multiple anti-convulsivant drugs.
Conclusion: A novel ABCC 8 gene mutation was responsible for congenital hyperinsulinism in our patient. Birth asphyxia due to macrosomia caused by the disease has worsened the neurological outcome.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology