RPL17 and multiple system atrophy: Post-hoc analysis showed that serum concentrations were significantly lower in patients with PD compared to Controls, but only tended to be lower in the MSA group compared to Controls, with no significant difference (PD vs. Control: p = 0.022; MSA vs. Control: p > 0.999; PD 1,608 ± 1,966 ng/mL, MSA 3,212 ± 3,172 ng/mL, Control 4,650 ± 5,308 ng/mL; Figure 2A).