Our case involved a monogenic cause of hyperinsulinism, which affects 1/50 000 live births, with the most severe forms being caused by inactivating mutations of the ABCC8 and KCNJ11 genes (1, 2) (that account for 36–70% of congenital hyperinsulinism cases) (3). This evidence concerns the gene ABCC8 and hyperinsulinism.