Changes in the expression of clock genes have been shown in an animal model of PD employing 6‐OHDA, with levels of expression of bmal1, per2 and clock genes, which were decreased in this model, but the transcription of rorα was increased and acetylation of bmal1 promoter was increased due to the reduction in NAD‐dependent deacetylase sirtuin‐1 (Wang et al., 2018). Here, CLOCK is linked to Parkinson disease.