The KEGG pathway “Neurotrophin signaling pathway” was significantly altered in PD patients with 13 miRNAs (miR-1, miR-331-5p, miR-153, miR-132-5p, miR-485-5p, miR-409-3p, miR-433, miR-370, let-7g-3p, miR-873-3p, miR-136-3p, miR-19b-3p, and miR-10a-5p) targeting 42 genes in the pathway map (Figure S3). Here, BDNF is linked to Parkinson disease.