A-synTotal and α-synOligo, CCL2, lactoferrin, norepinephrine, adrenaline, epinephrine, dopamine, α-2-macroglobulin, proteins involved in immune response, lipid metabolism and oxidative stress, protein deglycase DJ-1, S100 superfamily, peroxiredoxin-6, annexin-A5, and glutathione S-transferase-A1, apolipoprotein superfamily; preamine AIC, cathepsin D, acid ceramidase, transitional endoplasmic reticulum ATP-ase, cytoplasmic dynein-1 heavy chain, tripeptidyl-peptidase 1, CATD, ASAH1, and DYHC1 were shown to be potential biomarkers in PD. Here, CTSD is linked to Parkinson disease.