ABSTRACT Our long-term goal is to design a rational gene therapeutic approach to treat CEP290-LCA (Leber congenital amaurosis), one of the most severe and frequent causes of autosomal recessive retinal degenerative diseases that result in childhood blindness. The large size of the CEP290 gene has limited the development of successful gene delivery using conventional Adeno-associated Virus (AAV) vectors. Use of genome editing (such as CRISPR/Cas9 approach) and antisense oligonucleotide to correct a common deep intronic mutation is promising; however, these approaches are applicable to only one type of CEP290 mutation. Our aim is to develop a mutation-independent generic approach to treat CEP290-LCA. We propose to design shorter CEP290 (miniCEP290s) that are optimally functional and can be delivered using conventional AAV vectors. We have strong preliminary data that shows the development of a surrogate assay system that led to the identification of miniCEP290s. AAV-mediated delivery of these miniCEP290s improved the function and survival of the degenerating retina of mice carrying a mutation in the Cep290 gene (Cep290rd16). However, the effect was short-lived. In this application, we have proposed to improve the therapeutic response by generating better miniCEP290s and identifying the optimal dose, vectors and disease stage of intervention. The AAV-mediated delivery approach has been utilized successfully in several gene therapy studies and the promoters for photoreceptor-specific expression have been optimized. Thus, success obtained using the miniCEP290s can readily lead us to clinical trials. Our approach will also impact the development of similar strategies for other diseases, including Stargardt disease and Usher Syndrome, which are caused by mutations in large genes that are not amenable to delivery using conventional AAVs.