Persistent neonatal hypoglycemia Causes of persistent hypoglycemia include Hyperinsulinism Defective counter-regulatory hormone release (growth hormone, corticosteroids, glucagon, catecholamines) Inherited disorders of metabolism (eg, glycogen storage diseases, disorders of gluconeogenesis, fatty acid oxidation disorders) Although most hyperinsulinism is transient, less common and longer lasting causes include congenital hyperinsulinism (genetic conditions transmitted in both autosomal dominant and recessive fashion), severe erythroblastosis fetalis, and Beckwith-Wiedemann syndrome (in which islet cell hyperplasia accompanies features of macroglossia and umbilical hernia).