There were no significant differences in age (p = 0.558), sex (p = 0.356), and years of education (p = 0.265) between the SN + PD and SN − PD groups; however, they differed significantly in their total expression of tau-protein (p = 0.038) and many midbrain dPVS (p < 0.001). This evidence concerns the gene MAPT and Parkinson disease.