PARK7 and Parkinson disease: Our results showed that in the two CGIs that we probed, all the CpG sites were unmethylated in both PD group and NC group, indicating that CpG methylation in the promoter region of DJ-1 in PBLs might have very limited or no regulatory effects on DJ-1 expression and could not be used as a biomarker to reflect DJ-1 expression changes in brains of PD patients and NC.