SNCA and synucleinopathy: While the majority (94.2–99.9%) was localized to the PBS fraction (Fig. 5a), TrX-soluble α-synuclein was enriched 42-fold (5.7%) in cortical regions prone to developing severe synucleinopathy, and 26-fold (3.4% total) in healthy brain regions that were susceptible to developing moderate synucleinopathy upon PFF inoculation (OLF, STR, HIP, VMB; Fig. 5b).