Subjects were arbitrarialy classified as meeting the criteria for GH deficiency (GHD) when peak GH after stimulation with GHRH was ≤3 ng/mL; although GHRH alone is not a well-validated test for the diagnosis of GH deficiency, this cutoff point is based on standard criteria used to diagnose adults with hypopituitarism after various stimuli [37, 38]. This evidence concerns the gene GH1 and hypopituitarism.