Researchers from the Karolinska Institute in Sweden, in collaboration with Chinese universities and hospitals, have developed a gene therapy that restores hearing in individuals with congenital deafness or severe hearing loss. The therapy, administered through a single injection, targets mutations in the otoferlin (OTOF) gene, which is responsible for transmitting sound signals between the ear and brain. Clinical trial data published in Nature Medicine demonstrated that this AAV-OTOF gene therapy was safe and led to hearing improvements in 10 patients, including both children and adults, with follow-up periods ranging from six to twelve months. This approach offers a non-invasive alternative to cochlear implants, which require surgery, and represents a new treatment avenue for up to three in every 1,000 newborns affected by genetic hearing loss.