A Briard dog born blind with a mutation in the RPE65 gene that caused a dog-form of the human retinal degenerative disease called Leber congenital amaurosis (LCA). Lancelot has been treated with gene therapy and can now see.

As reported in the scientific journal, Nature Genetics, in 2001, researchers injected into one of Lancelot's eyes a "good" copy of the RPE65 gene that corrected his vision in that one eye. Since Lancelot's treatment, over 50 dogs have been treated in a similar manner and can now see. Three human clinical trials based upon this research began in 2007.