NF1 and neurofibromatosis type 1: The χ2 showed significant differences among the three groups according to Child Behavior Checklist (CBCL) Total Internalizing scale; in particular, the NF1 + OPG group showed a higher number of subjects with scores in pathological ranges (Adjusted Pearson Residuals = 1.6), while in the NF1 group the presence of borderline scores is significantly more frequent (Adjusted Pearson Residuals = 2.9).