Congenital deafness may soon be corrected, thanks to a gene therapy technique developed by researchers from Harvard Medical School and Boston Children's Hospital.
The researchers have worked together to develop a gene therapy technique used to correct loss of hearing in deaf mice. The study, which appeared in the journal Science Translational Medicine on Wednesday, focused on TMC1, a gene that commonly causes congenital hearing loss in humans.
According to a report in NBC news, the gene is responsible for four to eight percent of cases of loss of hearing, but scientists said the same technique could also be used to correct other forms of congenital deafness.
For the study, researchers used two deaf mutant mice. One mouse was deaf because of a deletion of the TMC1 gene, and researchers made it an appropriate model for recessive TMC1 mutations in humans, a congenital defect that usually causes deafness at a very young age, usually two years old.
The other mouse was deaf because of a rare TMC1 mutation, and this was used as an appropriate model for the "dominant TMC1-related deafness," which usually begins to cause hearing loss in people between 10 and 15 years of age.
With an engineered common cold-like virus, a corrected TMC1 gene was delivered to the mice's inner ears. Experiments revealed that after delivering the corrected gene, the mice were able to hear sounds. Researchers proved this by placing the mice inside a "startle box," where they were exposed to sudden, loud noises.
"Mice with TMC1 mutations will just sit there, but with gene therapy, they jump as high as a normal mouse," Jeffrey Holt, lead researcher of the study, said in a statement, according to Medical Daily.
Holt said the protocol was not ready for clinical trials, and there was a need to "tweak it a bit more." However, the team is hopeful that the breakthrough will serve as an important step toward the use of gene therapy as a method to treat deafness in humans.
Currently, cochlear implants and hearing aids are the only forms of therapy used in the management of hearing loss, and they are not entirely effective.
