Promising targets for gene therapy include Leber’s congenital amaurosis (LCA, inherited blindness)45, retinal dystrophy46,47, haemophilia A and haemophilia B48, DMD, SMA49, but also neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease50. This evidence concerns the gene DMD and Leber congenital amaurosis.