May be involved in ciliary biogenesis or function. Interacts with TMEM67. Localizes at the transition zone, a region between the basal body and the ciliary axoneme. Diffuse renal cyst development with tubulointerstitial nephropathy and disruption of tubular basement membranes in essentially normal-sized kidneys. Retinal lesions characterized by slow-onset loss of photoreceptors. Belongs to the TMEM218 family.