A stunning scientific discovery is taking place in the heart of Dongguan, China, bringing new hope to deaf kids and their families. Yiyi, a six-year-old child who was born completely deaf, is at the heart of this transformative story. Yiyi’s world was silent only a few months ago, and she had to rely on lip-reading and the goodwill of her peers to get by.

Thanks to developments in gene therapy, Yiyi’s inner ear cells, responsible for picking up vibrations and transmitting sound to her brain, were given the power to hear for the first time. 

How gene therapy repairs hearing pathways

A unique gene therapy study led by Dr. Yilai Shu and his team at Fudan University in Shanghai resulted in this life-changing breakthrough in repairing normal hearing pathways. “We were careful, and a little bit nervous, because it was the first in the world,” Dr. Shu, a surgeon and scientist at Fudan University in Shanghai confessed.

He and his team began their quest in December of last year, developing techniques through rigorous testing on mice and guinea pigs that eventually led to this world-first experiment in gene therapy for hearing restoration.

Gene therapy has had substantial results in the United States and Europe, such as restoring limited eyesight to persons with genetic blindness. However, no medicine or therapy has ever successfully improved hearing. 

Dr. Zheng-Yi Chen of Mass Eye and Ear in Boston, who was instrumental in the study’s development, underscores the significance of this achievement. “Before the treatment, if you put them in a movie theater with the loudest sound, they wouldn’t hear it,” he explained. “Now they can hear close to normal speech, and one can hear a whisper,” he added, which indicates a significant step forward in the fight to restore hearing.

Hope for congenital deafness

It is critical to emphasize that this gene therapy is intended to target a specific cause of congenital deafness – a deficiency in the gene responsible for creating a protein called otoferlin. This specific gene abnormality is responsible for between one and three percent of inborn deafness cases in China, resulting in approximately 900 new cases per year. While this is a rare ailment, the success of the Chinese gene treatment is expected to spark additional study and financing into other hereditary causes of deafness.

The science behind the miraculous

The breakthrough therapy is dependent on introducing a functional copy of the otoferlin gene, which is a difficult task due to the gene’s large size. To get around this, the gene was broken into two parts and carefully packed into millions of harmless viruses. Dr. Shu then injected these modified viruses deep into the children’s cochleas. These two DNA segments recombined inside the body to generate a full gene capable of creating the missing otoferlin protein.

This gene therapy’s significance goes beyond scientific achievements. The treated children’s parents have noticed revolutionary behavioral changes in their children. One toddler who had never talked before started saying “baba” and “mama” following the treatment. Dr. Shu emphasizes the need to start this therapy at an early age, ideally around one year old, because this coincides with a critical phase for speech development.

The possibility of gene therapy providing better hearing restoration than cochlear implants is an exciting development. Cochlear implants have difficulties, most notably in recording sound subtlety. There is promise for a more nuanced and comprehensive hearing experience with gene therapy, restoring not only the capacity to hear music but also the intricacies of nature, such as the wind rustling through the trees and birds singing.

Changing people’s lives through hearing and healing

This extraordinary accomplishment has set the ground for a global race in the field of genetic remedies for hearing loss. Western biotechnology firms, such as Akouos and Regeneron’s Decibel Therapeutics, are aggressively investigating gene treatments targeting the otoferlin gene. Eli Lilly purchased Akouos for $500 million, demonstrating the enormous interest in this area of study.

Shanghai Refreshgene Therapeutics, a modest biotech business with an aim to develop revolutionary and cheap gene therapies, sponsored the successful gene therapy in China. In this context, gene treatments for the eyes and ears hold great promise because they use far less material than typical IV infusions.

Noisy nights and a sound future

Yiyi and her family regard her improved hearing abilities as a miraculous gift. It does, however, come with its drawbacks. Yiyi, who lives on the 15th floor of a busy apartment complex, now complains about the noise at night. The rumbling of traffic, which was previously unheard, now reaches her windows, prompting her to unplug her cochlear implant, on which she had relied for years. It’s a monument to the gene therapy’s extraordinary success in bringing sound, with all of its delights and annoyances, into Yiyi’s life.

We are highlighting this piece as part of our annual “Best Of” roundup of articles published at The Optimist Daily this year. Today’s focus is on our staff’s picks! Our favorite solutions of 2023.