While a strong correlation was also seen between PD and PSP, we identified 11 proteins (SLC35A4, FTH1, MICOS10, SAR1B, RAB2A, CDC42, RHOA, GNA13, RAB35, YKT6, VPS13C) upregulated in PSP but downregulated in PD (and in MSA). Here, GNA13 is linked to multiple system atrophy.