New preclinical data support the development of a gene-editing strategy for restoring vision loss in patients with Leber congenital amaurosis type 10 (LCA10), an autosomal recessive condition caused by biallelic loss-of-function mutations in the CEP290 gene. Maeder and colleagues have developed EDIT-101, an experimental genome-editing medicine designed to remove the abnormal splice donor site caused by the IVS26 mutation in CEP290 (which most commonly causes LCA10), and thereby restore normal CEP290 expression. In their study, the researchers showed that subretinal delivery of EDIT-101 in a human CEP290 IVS26 knock-in mouse model resulted in fast and sustained CEP290 gene editing. They also demonstrated productive gene editing in a comparable surrogate nonhuman primate vector at levels meeting the target therapeutic threshold.