CLOCK and obesity due to melanocortin 4 receptor deficiency: Moreover, mice with mutations in clock genes encoding nuclear receptors have impaired glucose and lipid metabolism and are susceptible to diet-induced obesity and metabolic dysfunction, consistent with the idea that these genes control hepatic metabolic homeostasis (Delezie et al., 2012; Kudo et al., 2008; Lamia et al., 2008; Rey et al., 2011; Tong and Yin, 2013; Turek et al., 2005; Yang et al., 2006).