Just one injection enables five deaf children to hear for the first time
Six children who were born deaf have regained their hearing after undergoing an experimental treatment involving an injection directly into the ear. The treatment, developed by researchers from Fudan University in China and co-led by scientists from Harvard Medical School at Massachusetts Eye and Ear, targeted a specific genetic mutation responsible for inherited deafness.
The children, aged one to seven, all had a mutation in the OTOF gene, which affects the production of a protein crucial for transmitting signals from the ear to the brain. Over the 26-week trial period, five of the six children showed significant improvement in hearing, with four experiencing robust outcomes. The results, published in the journal Lancet, also revealed enhancements in speech perception among the responsive participants.
This breakthrough offers hope for treating various genetic forms of deafness and underscores the potential of gene therapy in addressing congenital hearing impairments. The targeted gene, OTOF, encodes the otoferlin protein, vital for relaying auditory signals from cochlear cells to nerves in the inner ear. By delivering a modified version of the gene using a viral vector, researchers successfully restored otoferlin production in the cochlea.
Despite facing initial challenges due to the gene's size, the team devised a solution by splitting the gene into two parts and delivering them separately. The injected viral mixture reached the target cells in the inner ear fluid, prompting the assembly of the complete protein. Within four to six weeks of treatment, participants began showing signs of hearing improvement.
The success of this approach, particularly in patients with cochlear implants, highlights its potential to complement existing hearing restoration methods. Notably, the therapy enabled older children with implants to understand and respond to speech without assistance, even in noisy environments. While the youngest participants exhibited positive trends, further evaluation is needed to gauge their long-term outcomes.
However, one participant did not respond to the treatment, possibly due to an immune response to the viral vector. Despite this setback, the promising results underscore the significance of targeted gene therapy in addressing genetic deafness, offering renewed hope for individuals with congenital hearing loss worldwide.