Under RT centrifugation, the levels of NFL (17.52 ± 10.37 pg/ml) in advanced PD were significantly higher compared with HCs (11.24 ± 4.06 pg/ml, P = 0.007, Figure 6C), but not significantly different between early PD (15.69 ± 9.74 pg/ml) and HCs (11.24 ± 4.06 pg/ml, P = 0.082). This evidence concerns the gene NEFL and Parkinson disease.