In a more recent study Vuralli et al. have retested all patients formerly diagnosed with GHD after only 1 year of treatment: the 40.6% of those with isolated GHD had a complete normalization of GH secretion, even if they had showed a severe deficiency with a very low GH-peak at diagnosis [46]. This evidence concerns the gene GH1 and hyperinsulinemic hypoglycemia, familial, 4.