SNCA and synucleinopathy: While immunohistochemical characterization of pS129 synucleinopathy in PFF mice allows visualization and semi-quantitative estimation of relative pS129 α-synuclein burden across different brain regions, it cannot provide pS129 or total α-synuclein concentrations nor inform on the proportion of α-synuclein S129 phosphorylation across different brain regions.