CLOCK and obesity due to melanocortin 4 receptor deficiency: In particular, rs7950226 (G>A) in the BMAL1 gene and rs1801260 (A>G), rs4864548 (G>A), and rs3736544 (G>A) in the CLOCK gene were reported to be significantly correlated with cardiovascular disease, obesity, metabolic syndrome, sleep reduction, and evening preference [22,23,24,25].