**5. Cilia-Related Proteins (Ciliopathies)**

Photoreceptors are non-motile sensory ciliated cells. The connecting cilium between inner and outer segmen<sup>t</sup> is critical for the transport of proteins to and from the outer segment. Many proteins are expressed in this region of photoreceptors and act to control the tra fficking of proteins. Ciliopathies is a general term used to group conditions resulting from mutations in cilia proteins. As cilia are present in many cell types, mutations in cilia proteins can cause syndromic disease where retinal degeneration is present, accompanied by disorders in other organ systems. Mutations that have a milder e ffect on function may result in a photoreceptor-only phenotype such as LCA or RP. A number of large animal models with mutations in cilia related genes have been identified (Table 1).
