In the current study, we identified five proteins (TFF3, CPB1, OPG, CNTN1, TIMP4) significantly different between PSP and PD patients by using PEA (OLINK) technology, and a combination of these protein levels showed a good performance in discriminating between these two diseases (AUC: 0.892) using a machine learning approach. This evidence concerns the gene CNTN1 and Parkinson disease.