Gene Therapy Cures Hearing in 10 Patients, Better in Children

Gene therapy can improve hearing in children and adults with congenital deafness or severe hearing loss, according to a study conducted by researchers at the Karolinska Institutet in Stockholm, in collaboration with Chinese hospitals and universities and published in the journal Nature Medicine. Hearing improved in all ten patients involved and the treatment was well tolerated. "This is a huge step forward in the genetic treatment of deafness, which can change the lives of children and adults," says Maoli Duan, consultant and lecturer at the Department of Clinical Science, Intervention and Technology at Karolinska. Duan is one of the authors of the study, which involved ten patients aged 1-24 years at five Chinese hospitals, all of whom have a genetic form of deafness or severe hearing loss caused by mutations in a gene called OTOF. These mutations cause a deficiency of the protein otoferlin, which plays a key role in transmitting hearing signals from the ear to the brain. The gene therapy involved using a vector virus to deliver a functional version of the OTOF gene into the inner ear via a single injection through a membrane at the base of the cochlea called the round window. The effect of the gene therapy was rapid, with most patients recovering some hearing after just one month. A six-month follow-up showed significant improvement in hearing in all participants, with the average volume of sounds audible increasing from 106 decibels to 52. Younger patients, particularly those between the ages of five and eight, responded best to the treatment. One participant, a seven-year-old girl, quickly recovered almost all of her hearing and was able to have daily conversations with her mother four months later.