Endocrine Abstracts

Introduction: Pallister–Hall syndrome (PHS) is characterized by a spectrum of anomalies which includes polydactyly, hypothalamic hamartoma, laryngotracheal cleft, bifid epiglottis, imperforate anus, and renal abnormalities. Hypoplastic cochlea is an infrequently reported association of PHS. The association of PHS with hyperinsulinaemic hypoglycaemia (HH) has not been previously reported in the literature.

Case report: A baby girl was born by elective caesarean section at 31 weeks of gestation with a birth weight of 1.2 kg (−1.2 SDS) to non-consanguineous Caucasian parents. She required ventilator support. The endotracheal intubation was extremely difficult due to a very narrow trachea. She was noted to be dysmorphic with two umbilical vessels, abnormal hands and feet and imperforate anus. MRI scan of the brain revealed the presence of a large hypothalamic hamartoma. The cochlea was noted to be truncated bilaterally with reduced number of turns. She was noted to have recurrent hypoglycaemic episodes in the first few days of life and required high concentration of glucose infusion to maintain normoglycemia (glucose infusion rate, 15 mg/kg per min). The investigations revealed a plasma insulin level of 65 pmol/l and C-peptide of 775 pmol/l during hypoglycaemia (blood glucose 1.4 mmol/l) confirming HH. The free fatty acids and β-hydroxy butyrate were suppressed. She was commenced on diazoxide and a good glycaemic response was noted. This enabled weaning down intravenous fluids and she was established on enteral feeds. The cytogenetic analysis revealed GLI3 mutation consistent with diagnosis of PHS.

Conclusion: This is the first reported case of HH in association with PHS. The genetic mechanism(s) in this syndrome that leads to dysregulated insulin secretion is unclear. Our patient also had hypoplastic cochlea which has been described only once before in the literature in association with PHS.