Preliminary results from studies in Belgium and Virginia offer hope for the future for hearing-impaired people. Estimates suggest that approximately 500 million people worldwide suffer from hearing loss.
Belgian scientists have identified the TGBF1 gene as the culprit in one of the most common forms of hearing loss in adults, otosclerosis. Otoschlerosis is a progressive form of hearing loss associated with the build-up of growing bone in the middle ear, blocking sound waves from reaching the inner ear. The current treatment options include hearing aids or surgery. The researchers are hoping that identification of the TGBF1 gene will lead to even better otosclerosis treatments in the future.
Many types of hearing loss are caused by deterioration of the hair cells in the inner ear. The hair cells process and transmit sound to the brain. Until now it has been considered impossible to regenerate hair cells in the ear once they disappear due to aging or exposure to excessive noise. But a new investigation found that regeneration of hair cells in the ear and, thus, restoration of hearing may be possible.
Scientists at the University of Virginia have done research into the KCNQ4 gene, which, when mutating, cause genetically conditioned hearing loss. The scientists constructed a correct form of the gene and created a gene-therapy delivery system that successfully transferred the KCNQ4 into human hair cells harvested from the inner ear.
“This proof-of-principle experiment showed that the system we developed works, and that KCNQ4 gene therapy might be an effective strategy to cure deafness in patients who carry mutations of that gene," said Professor Jeffrey Holt of the University of Virginia.