PKD1 and obesity due to melanocortin 4 receptor deficiency: GWAS studies show that PRKD gene is associated with body mass index (Speliotes et al., 2010; Comuzzie et al., 2012), suggesting the involvement of PKD-1 signaling in the pathobiology of diet-induced obesity (Huang et al., 2013; Dong et al., 2015; Yuan et al., 2015).