PER3 and obesity due to melanocortin 4 receptor deficiency: In a time-course experiment (Jakubowicz et al., 2017) with white adipose tissue biopsies from people with healthy weight or obesity or T2D, no variation in the rhythm and amplitude of core-clock (PER1, PER2, PER3, DBP, BMAL1, and CRY2), metabolic (PGC1), and clock-related (REVERB) genes could be observed in biopsy tissues (Jakubowicz et al., 2017).