Here at RestorEar, we are dedicated to combating hearing loss, particularly when it is due to loud noise exposure. Given that up to 65% of hearing loss in adults is due to causes like noise and trauma, this work is crucial. However, we are also excited about current developments pertaining to all types of hearing loss research. Here, we’d like to highlight one that has been gaining publicity in the news lately: gene therapy.

Gene therapy for hearing loss is an emerging field that aims to treat or potentially cure certain types of hearing impairments by correcting or replacing faulty genes responsible for the condition. It is particularly relevant for individuals with genetic forms of hearing loss– for instance, children. 

Here's an overview of how gene therapy for hearing loss works:

• Understanding the Genetic Basis: Hearing loss can be caused by mutations in various genes that are crucial for the development and function of the inner ear, particularly the hair cells and the sensory neurons responsible for transmitting auditory signals to the brain. Gene therapy is most applicable to individuals whose hearing loss is associated with a specific genetic mutation.
• Identifying the Target Gene: To develop a gene therapy approach, researchers first identify the specific gene or genes that are mutated and causing the hearing loss. Once the target gene is identified, the goal is to develop a therapeutic vector to deliver a functional copy of that gene into the affected cells of the inner ear.
• Delivery System: Gene therapy typically involves the use of viral vectors to introduce the corrected gene into the target cells. Adeno-associated viruses (AAVs) are commonly used for this purpose because they are relatively safe and efficient at delivering genes into cells. These viral vectors are modified to carry the functional gene without causing disease.
• Delivery Method: The viral vectors containing the functional gene are usually delivered directly into the inner ear, often through minimally invasive surgical procedures. This can include injections into the cochlea, the spiral-shaped, fluid-filled structure in the inner ear responsible for hearing.
• Gene Expression and Correction: Once the modified virus delivers the functional gene into the target cells, the gene begins to express and correct the underlying genetic defect. In the case of hearing loss, the goal is to restore the function of hair cells or sensory neurons, allowing for improved or restored hearing.
• Monitoring and Evaluation: Patients undergoing gene therapy for hearing loss will be closely monitored to assess the effectiveness and safety of the treatment. This may involve regular hearing tests and evaluations to measure improvements in hearing function.

Two US companies have recently launched clinical trials using gene therapy to try to restore hearing in children with a rare type of genetic hearing loss. These companies, Akouos and Decibel Therapeutics, are still in early stages of enrolling participants in multiple countries.