Current and future gene‐based therapies for Usher syndromes

Inherited retinal dystrophies are a group of genetically and clinically heterogeneous disorders characterized by photoreceptor degeneration. One common example is retinitis pigmentosa (RP), which is characterized by impaired night vision and progressively decreasing peripheral vision. Moreover, RP can be present as either an isolated visual defect or in association with extra ocular symptoms. The most common syndromic form is Usher syndrome, which is characterized by RP associated with neurosensory deafness of varying severity. The difficulty of this double handicap demands the development of novel therapies. The advantage of the Usher syndrome group is that each disease is monogenic thus lending themselves to gene‐based therapies. The caveat is that the most common forms are due to mutations in large genes, thus rendering gene replacement challenging. This talk will present an overview of current gene‐based therapies for Usher syndrome as a whole and will concentrate on novel genome‐editing advances for the most prevalent causative gene, USH2A .