BBS1 and obesity due to melanocortin 4 receptor deficiency: The notion that BBSome control of energy balance is not linked to cilia is further supported by the minimal or no effect on body weight and adiposity of loss of cilia (Ift88 gene) in the leptin sensitive neurons, whereas Bbs1 gene deletion in these same neurons causes frank obesity.20, 41 Rather, the BBSome appears to influence body weight through the regulation of the plasma localization of key receptors involved in energy homeostasis such as the 5-HT2CR.