Scientists Restore Hearing in People Born Deaf Through Groundbreaking Gene Therapy

Scientists have successfully restored hearing in both children and adults who were born deaf by repairing a single faulty gene, according to a groundbreaking study published in Nature Medicine. The international research team was led by scientists from Karolinska Institutet in Sweden, working in collaboration with several major hospitals and research centers in China. Their work represents a major milestone in the field of genetic medicine and offers new hope for people affected by inherited forms of deafness.

The researchers focused on mutations in the OTOF gene, which is responsible for producing otoferlin—a protein that plays a critical role in transmitting sound signals from the inner ear to the brain. In individuals born with defective OTOF genes, sound vibrations reach the inner ear normally, but the signals fail to be converted into nerve impulses. As a result, the auditory system does not function, even though the physical structure of the ear remains intact.

To correct this genetic defect, the team used a synthetic adeno-associated virus (AAV) as a delivery vehicle. This virus was engineered to carry a healthy copy of the OTOF gene and was injected directly into the cochlea in a single, minimally invasive procedure. AAVs are widely used in gene therapy research because of their ability to deliver genetic material safely and efficiently without causing disease.

According to the study’s findings, all ten participants experienced significant improvements in hearing within six months of receiving the treatment. On average, their hearing thresholds improved dramatically—from 106 decibels, which is considered profound deafness, to around 52 decibels, a level that allows people to hear normal speech and everyday sounds. This improvement represents a life-changing shift from near-total silence to functional hearing.

The therapy proved especially effective in younger patients, likely due to the greater neural plasticity of the developing brain. One of the most remarkable cases involved a seven-year-old girl who regained nearly full hearing. Just four months after treatment, she was able to hold daily conversations with her mother without assistance, demonstrating how quickly the brain can adapt once auditory input is restored. Nevertheless, adults in the study also showed meaningful improvements, indicating that the therapy may benefit a wide age range.

Importantly, no serious side effects were reported during the trial, suggesting that the treatment is both safe and well tolerated. While the study involved a small number of participants, the results strongly indicate that gene therapy could become a viable and effective treatment for certain inherited forms of deafness. The researchers note that this is the first documented case in which hearing has been restored in humans born deaf through the correction of a single gene.

Looking ahead, the research team plans to investigate whether similar gene-therapy techniques can be adapted to target other genes associated with more common types of hearing loss. According to the World Health Organization, over 430 million people worldwide live with disabling hearing loss, many of whom have genetic causes (WHO, 2023). Advances like this could eventually transform treatment options and reduce reliance on hearing aids or cochlear implants for select patients.

This study builds on decades of research into gene therapy and auditory neuroscience and aligns with broader findings from institutions such as the U.S. National Institutes of Health, which has highlighted gene therapy as a promising frontier for treating inherited sensory disorders (NIH, 2022). As further clinical trials are conducted, scientists hope this breakthrough will mark the beginning of a new era in personalized treatments for genetic hearing loss.

Sources:

• Nature Medicine (2024), Gene therapy for OTOF-related deafness

• Karolinska Institutet – Medical research on genetic hearing disorders

• World Health Organization (WHO), Deafness and hearing loss fact sheets

• U.S. National Institutes of Health (NIH), Gene therapy and sensory disorders