Holocarboxylase synthetase deficiency (#253, 270), 3-methylglutaconyl CoA hydratase deficiency (#250,950), 3-methylcrotonyl CoA carboxylase deficiency (#210,200 and #210,210), 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (#246,450). The gene discussed is HLCS; the disease is hyperinsulinemic hypoglycemia, familial, 4.