Genetic polymorphisms in these clock genes may also be related to fasting glucose (Bouatia-Naji et al., 2009; Englund et al., 2009; Dupuis et al., 2010; Dashti et al., 2015), insulin resistance (Lyssenko et al., 2009; Dashti et al., 2015), obesity (Garaulet et al., 2014), and type 2 diabetes (Bouatia-Naji et al., 2009; Voight et al., 2010; Bonnefond et al., 2012; Gaulton et al., 2015). This evidence concerns the gene CLOCK and obesity due to melanocortin 4 receptor deficiency.