Three genes responsible have been identified: intraflagellar transport (IFT)122 (WDR10),[2] IFT43—a subunit of the IFT complex A machinery of primary cilia,[3] and WDR35 (IFT121: TULP4)[4] It is also known as Sensenbrenner–Dorst–Owens syndrome, Levin syndrome I and cranioectodermal dysplasia (CED) These are pleomorphic and include[citation needed] Electroretinography shows gross abnormalities.

[5] They showed acromesomelic shortening, craniofacial characteristics with absence of craniosynostosis, small kidneys with tubular and glomerular microscopic cysts, persistent ductal plate with portal fibrosis in the liver, small adrenals, an enlarged cisterna magna and a posterior fossa cyst.

These complexes are involved in the coordinated movement of macromolecular cargo from the basal body along axonemal microtubules to the cilium tip and back again.

The anterograde movement of IFT particles out to the distal tip of cilia and flagella is driven by kinesin-2 while the retrograde movement of particles back to the cell body is driven by cytoplasmic dynein 1b/2[citation needed] The IFT-A protein complex is involved in retrograde ciliary transport.

Anterograde transport in the opposite direction remains normal resulting in accumulation of the IFT complex B proteins in the ciliary tip.