It’s music to our ears.
Approximately 11 million people in the US consider themselves deaf or severely hard of hearing.
No medications have been approved to treat hereditary hearing loss, but cochlear implants can help people with deafness perceive sound by bypassing damaged parts of the inner ear and directly stimulating the auditory nerve.
Now, a new gene therapy injection that restored hearing in people with mutations in the OTOF gene offers fresh hope.
Researchers injected an AAV vector carrying a healthy copy of the OTOF gene into the inner ear of 10 patients aged 1 to 24.
The OTOF gene encodes the protein otoferlin, which is essential for transmitting sound signals from the ear to the brain.
Without a functional OTOF gene, the critical connection between hair cells in the inner ear and the auditory nerve is disrupted.
Participants began to regain hearing in under a month, with the average perceptible sound threshold dropping from 106 decibels — the level of a lawn mower or motorcycle — to about 52 decibels — normal conversation level — within six months.
Younger participants fared best, especially those 5 to 8 years old.
In one remarkable case, a 7‑year‑old girl regained almost all her hearing and was able to hold a conversation with her mother just four months after treatment.
“This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults,” Maoli Duan, a consultant and docent at the Department of Clinical Science, Intervention and Technology at the Karolinska Institutet in Sweden, said in a statement.
“Smaller studies in China have previously shown positive results in children, but this is the first time that the method has been tested in teenagers and adults, too,” he added.
The therapy proved well-tolerated, with no serious side effects reported during the follow‑up period of six to 12 months.
The most common reaction was a temporary reduction in neutrophils, a type of white blood cell.
“Hearing was greatly improved in many of the participants, which can have a profound effect on their life quality,” Duan said. “We will now be following these patients to see how lasting the effect is.”
Duan noted that the OTOF gene is “just the beginning.”
“We and other researchers are expanding our work to other, more common genes that cause deafness, such as GJB2 and TMC1,” he added.
“These are more complicated to treat, but animal studies have so far returned promising results. We are confident that patients with different kinds of genetic deafness will one day be able to receive treatment.”
