FNDC4 and Parkinson disease: Through KEGG pathway analysis, it was confirmed that FNDC4 may be related to amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, non‐alcoholic fatty liver and cancer pathways and mainly affects the PI3K/Akt signalling pathway (Figure 4C, PRIDE database:PXD025623).