SNCA and Parkinson disease: By double immunolabeling of laminin α2 (brown) and α-synuclein (violet), we found that in the PD brains, α-synuclein-positive perivascular staining could be identified either in the outer (Figure 3G) and inner (Figure 3H) sides of the perivascular basement membrane, while in control brains, it did not show α-synuclein positivity in the proximity of laminin α2 staining (Figure 3I).