No significant differences were found in genotype distribution and MAFs for rs6356 in TH, rs921451 in DDC, rs4680 in COMT, and rs1611115 in DBH between PD patients and controls (for MAOB rs1799836, the comparison of genotype distribution and MAFs between patients and controls were according to different gender groups owing to this gene being located on the X chromosome; Tables 2, 3). This evidence concerns the gene MAOB and Parkinson disease.