Among the downregulated genes in PD (MSA-P > PD), key components included those involved in stress adaptation (HSP90AA1, GABRA6, NTRK3, DDX31), signal transduction (HSP90AA1, NTRK3, BTRC, PITPNM1, PPP2R2B), and ribosomal biogenesis (RPL27, DDX31) (Fig. 4E). This evidence concerns the gene PPP2R2B and Parkinson disease.