Gene Therapy for Inherited Retinal and Optic Nerve Disorders: Current Knowledge

The aim of this review is to provide a comprehensive summary of current gene therapy clinical trials for monogenic and optic nerve disorders. The number of genes for which gene-based therapies are being developed is growing. At the time of writing this review gene-based clinical trials have been registered for Leber congenital amaurosis 2 (LCA2), retinitis pigmentosa 38, Usher syndrome 1B, Stargardt disease, choroideremia, achromatopsia, Leber hereditary optic neuropathy (LHON) and X-linked retinoschisis. Apart from RPE65 gene therapy for LCA2 and MT-ND4 for LHON which has reached phase III, all other trials are in investigation phase I and II, i.e. testing the efficacy and safety. Because of the relatively easy accessibility of the retina and its ease of visualization which allows monitoring of efficacy, gene-based therapies for inherited retinal disorders represent a very promising treatment option. With the development of novel therapeutic approaches, the importance of establishing not only clinical but also molecular genetic diagnosis is obvious.