MKS1 and obesity due to melanocortin 4 receptor deficiency: MKS1 is a TZ protein found in MKS, JBTS, and Bardet–Biedl syndrome (BBS), which is a ciliopathy characterized by obesity, retinitis pigmentosa, polydactyly, intellectual disability, and renal abnormalities (Kyttala et al., 2006; Dawe et al., 2007; Slaats et al., 2016).