11-Year-Old Boy with Hearing Loss Hears Father’s Voice for First Time Thanks to Gene Therapy
An 11-year-old boy born deaf in both ears has been able to hear his father’s voice for the first time, thanks to the effects of gene therapy applied to hearing loss. The breakthrough treatment was conducted at the Children’s Hospital of Philadelphia (CHOP), which announced the groundbreaking news.
“This therapy has been in the works for over 20 years, and it’s finally here,” said surgeon John Germiller, director of clinical research for CHOP’s division of otolaryngology. “While the gene therapy we performed on our patient aimed to correct an anomaly in a very rare gene, these studies could open the door to future use for some of the more than 150 other genes that cause childhood hearing loss.”
The child was born deaf due to a defective gene that prevents the production of otoferlin, a protein necessary for the “hair cells” of the inner ear to convert sound vibrations into chemical signals that are sent to the brain. Gene therapy replaced the defective gene within the cell’s DNA with the “healthy” gene, which was inserted into the ear via a harmless virus, used as a vector and modified to carry working copies of the otoferlin gene. As a result, the hair cells began to produce the missing protein and function properly. Just four months after the surgery, the patient’s current hearing loss has improved so much that it was only classified as “mild to moderate,” when it was previously total.
The US Food and Drug Administration gave the green light to the study, wanting to start the research on older children first, for safety reasons, even though the “window” for acquiring speech closes around five years of age. The 11-year-old may not learn to speak, but now he hears sounds.
“As more and more patients of different ages are treated with this gene therapy, researchers will learn more about the degree of improvement in hearing and whether that level of hearing can be sustained for many years,” Germiller said.
This breakthrough offers hope for children with hearing loss and paves the way for further advancements in gene therapy for a variety of genetic conditions.