Among PD patients, the expression levels of total tau did not correlate with either cognitive decline (r = 0.13, p = 0.25 by Spearman correlation analysis, Supplementary Figure S2B) or scores of MMSE (r = -0.21, p = 0.25 by Spearman correlation analysis, Supplementary Figure S3B). This evidence concerns the gene MAPT and Mental deterioration.