Restoring and preserving high-acuity hearing is one of the greatest unmet challenges of medicine: 360 million people worldwide have disabling hearing loss, but there are no FDA-approved therapies to address it. We are developing targeted adeno-associated viral vector (AAV)-based gene therapies for sensorineural hearing loss, which results from dysfunction or damage to sensory cells and/or nerve fibers of the inner ear. Sensorineural hearing loss is found in most cases of newborn deafness and affects nearly a quarter of all adults over the age of 65, making it the most common form of hearing loss and one of the most common of all sensory disorders.