Obesity is also a symptom of melanocortin 4 receptor (MC4R) mutations that impair its ciliary localization in both humans and mice, suggesting that ciliary localization is essential for the functionality of this GPCR receptor (Davenport et al., 2007; Siljee et al., 2018). The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.