Supplementary Material for: A dual etiology of neonatal hypoglycemia secondary to FOXA2 heterozygous deletion

Neonatal hypoglycemia is a critical pediatric condition that requires prompt diagnosis and treatment to prevent long-term neurological damage. This case study reports a female newborn with recurrent hypoglycemia within hours of birth. There was no family history of hypoglycemia or diabetes. The pregnancy was unremarkable, with no gestational diabetes and no abnormalities were detected on prenatal ultrasounds. The girl was born at 36 weeks of gestation by emergency caesarean section due to an abnormal fetal heart rate and with normal parameters. A biological assessment carried out at the time of hypoglycemia revealed somatotropic, thyrotropic and corticotropic insufficiencies. A brain MRI showed hypoplasia of the anterior pituitary gland and interruption of the pituitary stalk, as well as an ectopic posterior pituitary gland on the floor of the third ventricle. Altogether, these findings led to the diagnosis of congenital panhypopituitarism secondary to pituitary stalk interruption syndrome. Hormone replacement therapy was initiated. Despite that treatment, hypoglycemia persisted, new assessments revealed congenital hyperinsulinism, and treatment with diazoxide was initiated, leading to stabilization of blood glucose levels. Genetic testing identified a FOXA2 heterozygous deletion resulting in both congenital hyperinsulinism and congenital panhypopituitarism. The role of the FOXA2 gene in both conditions highlights the need for awareness and precise diagnosis to ensure timely and appropriate treatment. This case underscores the complexity of neonatal hypoglycemia, where dual endocrine pathologies can co-exist, necessitating comprehensive and careful evaluation.