Participants with DLB were also more likely than those without DLB to have EPVS in the basal ganglia (BG-PVS; 62.5% vs. 24.7%, p = 0.006), higher plasma neurofilament light chain (NfL) concentrations (median value: 31.4 vs. 21.3 pg/mL, p = 0.001), and higher scores in the voxel-based specific regional analysis system for Alzheimer’s Disease (VSRAD; median score: 1.05 vs. 0.84, p = 0.020). This evidence concerns the gene NEFL and early-onset autosomal dominant Alzheimer disease.