Gene Therapy Using a miniCEP290 Fragment Delays Photoreceptor Degeneration in a Mouse Model of Leber Congenital Amaurosis

Mutations in the cilia-centrosomal protein CEP290 are frequently observed in autosomal recessive childhood blindness disorder Leber congenital amaurosis (LCA). No treatment or cure currently exists for this disorder. The Cep290 (retinal degeneration 16) mouse (a model of LCA) carries a mutation in the Cep290 gene. This mutation leads to shorter cilia formation and defective photoreceptor structure and function. A roadblock to developing a gene replacement strategy for CEP290 using conventional adeno-associated virus (AAV) vectors is its large size. The identification and characterization is reported of a miniCEP290 gene that is amenable to AAV2/8-mediated delivery and delaying retinal degeneration in the Cep290 mice. Using the ability of Cep290 mouse embryonic fibroblasts to from shorter cilia as a platform, a human CEP290 domain encoded by amino acids 580-1180 (miniCEP290 ) was identified that can recover the cilia length in vitro. Furthermore, subretinal injection of AAV particles carrying the cDNA expressing miniCEP290 into neonatal Cep290 mice resulted in significantly improved photoreceptor survival, morphology, and function compared to control injected mice. These studies show the potential of using a truncated CEP290 to treat this fast progressing and devastating disease.