Then, the CSF SV2A levels in the AD, VaD, and PDD groups were compared, revealing that the average CSF SV2A level was significantly lower in the AD group than in the other two groups, which demonstrated high diagnostic efficacy in the differential diagnosis of AD from VaD (AUC = 90.5%, 95% CI = 0.800–0.966, sensitivity = 84.78%, specificity = 92.31%) (Fig. 2k) and PDD (AUC = 91.8%, 95% CI = 0.817–0.974, sensitivity = 84.78%, specificity = 100.00%) (Fig. 2l). The gene discussed is SV2A; the disease is Alzheimer disease.