In 2006, Choi et al. [52] found the presence of oxidatively damaged DJ-1 in idiopathic PD and AD brains, and subsequent work detected a significant increase in oxidized DJ-1 in the erythrocytes of unmedicated PD patients versus medicated PD patients and healthy subjects, suggesting oxidized DJ-1 might be a useful biomarker for the detection and diagnosis of early stage PD [55]. This evidence concerns the gene PARK7 and Alzheimer disease.