MAPT and Alzheimer disease: In PD patients, a linear mixed model (LMM) for time-varying CSF p-tau/Aβ showed that GRS-AD, time, and GRS-PD*time were associated with time-varying CSF p-tau/Aβ, while GRS-PD, GRS-AD*time, and time-varying CSF αSyn were not (Table 3).