Consistent with their structural importance, single missense mutations or compound heterozygous variations in the first four TPRs of human IFT121, IFT122, IFT140 and IFT144 cause multiple ciliopathies, including Cranioectodermal dysplasia, Leber congenital amaurosis, and Short-rib thoracic dysplasia33–36. This evidence concerns the gene WDR19 and cranioectodermal dysplasia.