Implicated individuals regained their hearing in a matter of weeks following a groundbreaking injection.

A groundbreaking gene therapy has brought fresh hope to millions of people living with deafness caused by mutations in the OTOF gene. Researchers at various institutions focusing on genetic hearing loss have been exploring different approaches, including gene replacement, gene correction using viral vectors or CRISPR, and hair cell regeneration, primarily in animal models.

The therapy, which involves injecting an AAV vector carrying a healthy copy of the OTOF gene into the inner ear, was tested on 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.

In a promising development, a 7-year-old girl regained almost all her hearing four months after the treatment. Younger participants, especially those aged 5 to 8, fared best in the treatment. Participants began to regain hearing in under a month after the treatment, with the average perceptible sound threshold dropping from 106 decibels to about 52 decibels within six months.

The treatment has the potential to significantly improve the lives of those affected, as hearing was greatly improved in many of the participants. Without a functional OTOF gene, the critical connection between hair cells in the inner ear and the auditory nerve is disrupted, leading to deafness.

Researchers plan to follow these patients to determine the lasting effect of the treatment. The most common reaction was a temporary reduction in neutrophils, a type of white blood cell. However, no serious side effects were reported during the six to 12-month follow-up period.

Maoli Duan, a consultant and docent at the Department of Clinical Science, Intervention and Technology at the Karolinska Institutet in Sweden, expressed optimism about the gene therapy's potential. The OTOF gene is just the beginning, and researchers are expanding their work to other genes such as GJB2 and TMC1.

It's important to note that no medications have been approved to treat hereditary hearing loss. Cochlear implants can help people with deafness perceive sound by bypassing damaged parts of the inner ear and directly stimulating the auditory nerve. However, the new gene therapy offers a more targeted and potentially curative approach.

Approximately 11 million people in the US consider themselves deaf or severely hard of hearing. With ongoing research and advancements in gene therapies, patients with different kinds of genetic deafness may one day be able to receive treatment. The researchers tested the gene therapy on teenagers and adults, in addition to children, marking a significant step towards making this treatment accessible to a wider population.

Implicated individuals regained their hearing in a matter of weeks following a groundbreaking injection.