AHI1 and Retinal dystrophy: Given the strong conservation of the retina between human and zebrafish and the almost constant retinal involvement in zebrafish ciliopathy mutants, most data are available on this organ system, with thoroughly studied mutants for cc2d2a, talpid3, ift172 and ahi1. Interestingly, even though these four mutants all display some degree of retinal dystrophy, which in patients would be considered as “the same phenotype,” the underlying mechanism appears to be radically different.