A ciliopathy with multisystem involvement. It is invariantly characterized by rod-cone dystrophy, and at least three additional non-ocular features such as intellectual disability, obesity, polydactyly, hypogonadism, or renal anomalies as primary manifestations. In the absence of one of these four primary clinical features, the diagnosis of BBS is made when at least two secondary features are observed, including hepatic fibrosis, diabetes mellitus, reproductive and developmental abnormalities, growth retardation, speech delays, or cardiovascular problems