Longitudinal studies that evaluated longitudinal changes of CSF proteins (α-syn, t-tau, p-tau, and Aβ1−42) levels in PD patients have reached heterogeneous results e.g., the study conducted by Hall et al. has shown significantly increasing levels of all proteins except Aβ1−42 during a two-year follow-up, in which increase of p-tau was associated with motor symptoms aggravation and cognitive decline (21). Here, MAPT is linked to Parkinson disease.