ABCC8 and hyperinsulinemic hypoglycemia: Activating mutations in the ABCC8 gene, which encodes the SUR1 protein, have previously been described as a cause of neonatal diabetes or maturity-onset diabetes of the young (MODY) [2, 3], whereas inactivating mutations in this gene usually lead to hyperinsulinemia hypoglycemia (HI) in infancy [4, 5].