RPE65 and Leber congenital amaurosis: Regarding assessments of the potential efficacy of 9-cis retinal therapy in human subjects, three investigations having so far been reported: two of these in patients with LCA [62] and arRP [63] caused by bi-allelic recessive mutation within the LRAT or RPE65 genes and one in subjects with late onset adRP expressing the heterozygous, dominant RPE65 variant D477G [39], the latter suggesting that this treatment may represent a therapeutic option for dominant D477G RPE65 patients.