In another study evaluating NF1 cases receiving GH treatment, the growth rate, which was 5 cm/year before GH therapy, increased to 9 cm/year at the first year of therapy, was 8.3 cm/year in the second year, and decreased to 6 cm/year between the third and the fifth years of treatment (15). This evidence concerns the gene GH1 and neurofibromatosis type 1.