A 38-year-old Italian man has become the first person in the world to benefit from an innovative dual-vector gene therapy for a rare inherited eye disease. Treated in July 2024 at the University of Campania “Luigi Vanvitelli” in Naples, the patient was diagnosed with Usher syndrome type 1B, a genetic disorder that causes congenital deafness and progressive vision loss.

The therapy, developed by the Telethon Institute of Genetics and Medicine in Pozzuoli, addresses a major challenge in gene therapy: the gene responsible for Usher 1B, MYO7A, is too large to be delivered by a single viral vector. Scientists solved this by splitting the gene in half and using two separate adeno-associated viral (AAV) vectors. Once injected into the subretinal space, the two gene fragments recombine within the cells, restoring the production of the essential protein.