“Auditory neuropathy can be due to a variation in a single gene—known as the OTOF gene—which produces a protein called otoferlin. This protein typically allows the inner hair cells in the ear to communicate with the hearing nerve. … The new gene therapy aims to deliver a working copy of the faulty OTOF gene using a modified, non-pathogenic virus. It will be delivered via an injection into the cochlea under general anesthetic.”
From Ars Technica.