Jerusalem, 27 October, 2025 (TPS-IL) — Israeli and U.S. scientists have developed a gene therapy that could dramatically improve the lives of people with hearing and balance disorders caused by inner ear dysfunction, Tel Aviv University announced. The new approach not only protects the cells responsible for these senses but does so more efficiently than existing treatments, potentially offering long-term relief for conditions that currently have no cure.
Hearing loss is one of the most common sensory impairments worldwide, affecting hundreds of millions of people. According to the World Health Organization, over 430 million people globally experience disabling hearing loss, and this number is projected to rise to over 700 million by 2050. About half of congenital hearing loss cases — meaning hearing loss present from birth — are caused by genetic factors, which is exactly the kind of problem this new therapy targets.
Furthermore, balance disorders linked to inner ear dysfunction are also widespread, especially among older adults. Vertigo and chronic vestibular problems affect an estimated 15–20% of adults at some point in their lives, often leading to falls, injuries, and reduced quality of life. When balance disorders are caused by genetic inner ear defects, there are currently no treatments that prevent progression. Treatment focuses on symptom management or rehabilitation.
The new gene therapy “constitutes an improvement over existing strategies, demonstrating enhanced efficiency and holds promise for treating a wide range of mutations that cause hearing loss,” said Prof. Karen Avraham, Dean of the Gray Faculty of Medical & Health Sciences, who led the study alongside PhD student Roni Hahn. The research, conducted with Prof. Jeffrey Holt and Dr. Gwenaëlle Géléoc from Boston Children’s Hospital and Harvard Medical School, was supported by the US-Israel Binational Science Foundation, the National Institutes of Health/NIDCD, and the Israel Science Foundation Breakthrough Research Program.
The study was published in the peer-reviewed EMBO Molecular Medicine journal.
Therapy Ahat Addresses Both Issues
“The inner ear consists of two highly coordinated systems: the auditory system, which detects, processes, and transmits sound signals to the brain, and the vestibular system, which enables spatial orientation and balance. A wide range of genetic variants can affect these systems, leading to sensorineural hearing loss and balance problems. Hearing loss is the most common sensory impairment worldwide, and over half of congenital cases are caused by genetic factors,” Avraham explained. “Current treatments can assist with sound perception but do not prevent cell degeneration or restore balance. Our goal was to develop a therapy that addresses both issues.”
Hahn described the therapeutic strategy. “Gene therapy has emerged as a powerful approach for a range of genetic disorders, including spinal muscular atrophy and Leber congenital amaurosis, as well as in cancer immunotherapy. We use engineered viral vectors to deliver functional copies of genes directly into target cells. Many therapies rely on adeno-associated viruses (AAVs), which are now showing promise in clinical trials for hearing loss.”
The team focused on mutations in the CLIC5 gene, which are essential for maintaining hair cells in the inner ear. Loss of CLIC5 leads first to hearing impairment and later to balance problems. Using a self-complementary AAV vector, or scAAV, the therapy achieved faster and more efficient delivery to hair cells while using lower doses than conventional approaches. In treated animal models, it prevented hair cell degeneration and preserved both hearing and balance.
The new gene therapy could fundamentally change the treatment landscape for people born with genetic hearing and balance disorders. By directly targeting mutations in genes such as CLIC5, the therapy has the potential to prevent or even reverse hearing loss before it becomes severe, offering a level of intervention beyond what hearing aids or cochlear implants can provide. At the same time, it protects the delicate hair cells responsible for balance, which could reduce or prevent vestibular problems that often lead to falls and injuries.
Researchers believe the approach could be adapted to address a wide range of genetic mutations that cause inner ear dysfunction, opening the door for treatments that help far more people than current therapies do. For children born with congenital defects, early intervention could ensure normal development of hearing and balance, dramatically improving quality of life and reducing the need for long-term medical or rehabilitative support.
“For millions of people worldwide, this could mean preventing progressive disability rather than just managing symptoms. We hope these findings will pave the way for gene therapies that truly restore quality of life,” Avraham said.
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