*3.3. RDH5*

Recently, a cat model with a mutation in another visual cycle gene, *Rdh5*, has been identified by our group [64]. Rdh5 functions to convert 11-cis-retinol to 11-cis-retinal for transport to photoreceptors for reforming the visual pigments. In humans, *RDH5* mutations cause a variety of phenotypes. Fundus albipuncatatus is the predominant phenotype [65] but a subset of patients have macular atrophy [66–69] or cone dystrophy [70]. The *Rdh5*-mutant cat promises to be a valuable model because the *Rdh5*−/− mouse lacks a phenotype and does not recapitulate *RDH5*-retinopathy in human patients [71]. In contrast, the cat model, similar to a ffected humans, shows a very delayed recovery of photoreceptor function following light exposure and recapitulates the *RDH5*-macular atrophy phenotype.
