The aims of this study were to (1) map the distribution and alterations of SV2A and SYP in the brains of AD patients compared with NCs; (2) assess the associations of SV2A and SYP with Aβ, tau, and the apolipoprotein E (APOE) ε4 allele in the brains of AD patients and NCs; and (3) understand the associations between SV2A and other synaptic markers in EVs. The gene discussed is APOE; the disease is Alzheimer disease.