Of these, only CHCHD2 mRNA consistently demonstrated significantly reduced expression in all PD groups compared to the control group [Fig. 1a, F(3, 4) = 52.0, one-way ANOVA, n = 3; p < 0.01 for Early or Mid PD vs. control, p < 0.001 for Late PD vs. control]. Here, CHCHD2 is linked to Parkinson disease.