Whether this is the sole binding site for the IFT complexes awaits further investigation, especially as other IFT-B subunits including IFT25 (Eguether et al., 2014), IFT27 (Aldahmesh et al., 2014; Eguether et al., 2014; Liew et al., 2014), IFT74 (Lindstrand et al., 2016) and IFT172 (Schaefer et al., 2016) are either genetically associated with BBS or have been associated with BBSome exit from the cilium. This evidence concerns the gene IFT172 and Bardet-Biedl syndrome.