KEGG enrichment analysis showed that the key genes were enriched in pathways of both expected and potential novel, such as the well-known tyrosine metabolism, calcium signaling pathway, dopaminergic synapse, synaptic vesicle cycle, and Parkinson disease, and the less expected neuroactive ligand-receptor interaction, gap junction, PPAR signaling pathway, and Fc gamma R-mediated phagocytosis (Figures 3B,C). This evidence concerns the gene PPARA and Parkinson disease.