SV2A and Parkinson disease: Synaptophysin density (PD + PDD + DLB: r = -0.12, R2 = 1%, p = 0.006) and SV2A (PD + PDD + DLB: r = -0.18, R2 = 3%, p < 0.001), negatively correlated with LB density across all regions in the disease groups.