SNCA and Parkinson disease: The pS129-α-synuclein levels were 13.7 ± 6.8 fg/mL, 11.5 ± 7.5 fg/mL, and 12.8 ± 7.1 fg/mL for the PD with normal cognition, PD-MCI, and PDD groups, respectively (p = 0.75).