SNCA and Parkinson disease: McMillan et al. (2017) observed that miR-7 can combine with the 3′-untranslated region (UTR) of SNCA mRNA to inhibit its transcription, and loss of miR-7 leads to α-syn aggregation and dopaminergic neuronal loss in the brains of PD patients (McMillan et al., 2017). Chen et al. (2017) found significantly upregulated expression of miR-4639-5p in PD patients, which negatively regulated the post-transcription level of the PD-associated gene DJ-1, eventually causing severe oxidative stress and neuronal death (Chen et al., 2017).