Deafness reversed: One injection restores hearing in just weeks
- World Half Full
- Apr 2
- 2 min read
SCIENCE
Swedish scientists say gene therapy can significantly improve hearing in people born with congenital deafness or severe hearing loss. Researchers at the Karolinska Institutet, working with hospitals and universities in China, are reporting notable hearing improvements for each of ten patients.
“This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults,” says Maoli Duan, consultant and docent at Karolinska’s Department of Clinical Science, Intervention and Technology, and one of the study’s corresponding authors.
The trial’s participants were between the ages of 1 and 24; all had a genetic form of deafness linked to mutations in a gene called OTOF. These mutations prevent the body from producing enough of the protein otoferlin, which is essential for sending sound signals from the inner ear to the brain.
To address this, researchers used a synthetic adeno-associated virus (AAV) to deliver a working version of the OTOF gene directly to the inner ear via a single injection through a membrane at the base of the cochlea known as the round window.
Most patients began to regain some hearing within a month. After six months, all participants showed clear improvement. On average, the level of sound they could detect improved from 106 decibels to 52, roughly the difference between a chainsaw and normal conversation.
Children showed the most dramatic responses, especially those between the ages of five and eight. One seven-year-old girl regained nearly full hearing and was able to have everyday conversations with her mother just four months after treatment. At the same time, the therapy also produced meaningful improvements in adults.
“Smaller studies in China have previously shown positive results in children, but this is the first time the method has been tested in teenagers and adults, too,” says Duan. “Hearing was greatly improved in many of the participants, which can have a profound effect on their quality of life. We will now be following these patients to see how lasting the effect is.”
The therapy has been shown to be safe and well-tolerated. The most commonly reported side effect was a decrease in neutrophils, which are a type of white blood cell. No serious adverse reactions were observed during the follow-up period of 6 to 12 months.
“OTOF is just the beginning,” says Duan. “We and other researchers are expanding our work to other, more common genes that cause deafness, such as GJB2 and TMC1. 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.”
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