To determine if the inhibitory effect of lipoproteins on α-syn spontaneous aggregation also affects the seeded aggregation of α-syn intrinsic to SAAs, we used a highly sensitive and specific diagnostic α-syn SAA that can amplify α-syn seeds directly from PD/DLB/MSA CSF while showing no spontaneous aggregation with healthy control (HC) CSF [9, 19]. This evidence concerns the gene PCSK1N and multiple system atrophy.