PER2 and type 2 diabetes mellitus: For example, subcutaneous white adipose tissue biopsies showed no difference of rhythm and amplitude of core-clock (PER1, PER2, PER3, CRY2, BMAL1, and DBP), clock-related (REVERBα), and metabolic (PGC1α) genes between individuals with normal weight, obesity, or T2D over a time-course experiment (9).