GCG and hyperinsulinemic hypoglycemia, familial, 4: A glucagon test performed at the age of 10 years revealed a normal GH peak of 10 μg/L with a normal cortisol concentration; however, rhGH treatment (0.022 mg/kg/day) was started at the age of 12 years, due to growth failure with a low IGF1 concentration (61 ng/mL), suggestive of IGF1 deficiency (Table 2).