IFT54 and retinal degeneration: There can also be neurological (developmental delay, cerebellar atrophy, molar tooth sign), limb, and craniofacial anomalies that overlap with features of Joubert, oral–facial–digital, and Pallister–Hall syndromes (CLUAP1/IFT38, IFT56, IFT74, IFT81), in addition to Bardet–Biedl syndrome, i.e. developmental delay, retinal degeneration, polydactyly, obesity, and hypogonadism (IFT27, IFT74, TRAF3IP1/IFT54, IFT172).