PCSK9 and Parkinson disease: Multivariate regression, receiver operating characteristic (ROC) analysis, and bioinformatics tools were employed to evaluate diagnostic potential and pathway associations.<h4>Results</h4>PD patients showed significantly lower MoCA and MMSE scores than HC, accompanied by elevated serum ICAM-1, PCSK9, and JAK1, and decreased INPP5D and FLNA.