As the most common subtype of Leber congenital amaurosis (LCA), LCA10 is a 
severe retinal dystrophy caused by mutations in the CEP290 gene. The most 
frequent mutation found in patients with LCA10 is a deep intronic mutation in 
CEP290 that generates a cryptic splice donor site. The large size of the CEP290 
gene prevents its use in adeno-associated virus (AAV)-mediated gene augmentation 
therapy. Here, we show that targeted genomic deletion using the clustered 
regularly interspaced short palindromic repeats (CRISPR)/Cas9 system represents 
a promising therapeutic approach for the treatment of patients with LCA10 
bearing the CEP290 splice mutation. We generated a cellular model of LCA10 by 
introducing the CEP290 splice mutation into 293FT cells and we showed that guide 
RNA pairs coupled with SpCas9 were highly efficient at removing the intronic 
splice mutation and restoring the expression of wild-type CEP290. In addition, 
we demonstrated that a dual AAV system could effectively delete an intronic 
fragment of the Cep290 gene in the mouse retina. To minimize the immune response 
to prolonged expression of SpCas9, we developed a self-limiting CRISPR/Cas9 
system that minimizes the duration of SpCas9 expression. These results support 
further studies to determine the therapeutic potential of CRISPR/Cas9-based 
strategies for the treatment of patients with LCA10.