OFD1 and ciliopathy: Severe gene mutations involved in ciliogenesis are either lethal or cause severe syndromic ciliopathies, whereas milder alleles show a more restricted phenotype and affect only particular ciliated organs (retina, cochlea, renal tubules...)[51], e.g. CEP290 cause Leber Congenital Amaurosis[52], and OFD1 is responsible for severe X-linked RP[53] as well as oro-facial-digital syndrome I, characterized by craniofacial, oral and skeletal abnormalities[54] or other syndromic diseases[55].