IFT81 and Bardet-Biedl syndrome: Human patients with variants in IFT-B encoding genes have been previously described for the subunits IFT27 (BBS) [50,51], IFT52 (SRPS) [52,53], IFT54/TRAF3IP1 (Senior-Loken syndrome) [54], IFT56/TTC26 (biliary, renal, neurologic, and skeletal syndrome) [55], IFT57 (orofaciodigital syndrome) [56], IFT80 (SRPS) [57], IFT81 (SRPS) [58], and IFT172 (SRPS) [59].