Regarding the differences in facial growth according to the origin of growth deficiency, girls with ISS (109.38 ± 3.62 mm [p < 0.01]) presented a significantly greater amount of mandibular growth than those with GHD (104.88 ± 2.08 mm [p < 0.01]) during GH treatment, when compared to those considered healthy (control group). This evidence concerns the gene GH1 and Growth delay.