NR1D1 and airway hyperresponsiveness: Studies have shown that the clock protein REV-ERBα controls airway hyperresponsiveness at different times of day, and that knocking down the Rev-erbα gene abolishes the time-of-day effect.6 7 The results from our study are consistent with the recently published RADicA study, which in a relatively small sample of patients with suspected asthma found that patients self-reported their worst symptoms in the morning and night, and that patients were more likely to demonstrate bronchodilator responsiveness in the morning compared with the afternoon.8