LMM for time-varying CSF αSyn showed that the effects of GRS-AD, time, GRS-AD*GRS-PD, GRS-AD*time, GRS-AD*GRS-PD*time, and time-varying CSF p-tau/Aβ were significant, while those of GRS-PD and GRS-PD*time were not. The gene discussed is MAPT; the disease is Alzheimer disease.