Among PD patients, those with pRBD (n = 88) had significantly lower expression levels of all five clock genes compared with those in HC (n = 314, P < 0.05, Figures 2A–E), in particular, they had lower expression levels of BMAL1 when comparing to the PD patients without pRBD (n = 176, P < 0.05, Figure 2A). The gene discussed is CLOCK; the disease is Parkinson disease.