The levels of ferritin in the PD group were significantly higher than those in the control group (406.46 ± 241.86 vs. 245.62 ± 165.47 ng/μg, P = 0.001) (Figure 3A), and the levels of TfR in the PD group were also significantly higher than those in the control group (1,728.94 ± 766.71 vs. 1,153.92 ± 539.30 ng/μg, P < 0.001) (Figure 3B). The gene discussed is TFRC; the disease is Parkinson disease.