A newly published meta-analysis has uncovered 10 new genetic variants that contribute to age-related hearing loss. The findings indicate a part of the ear known as the stria vascularis may play a part in hearing impairment.
Age-related hearing loss is so prevalent most people take it for granted as a regular expected part of aging. But many researchers believe it doesn’t have to be that way, and recent studies have pointed to novel ways to either prevent hearing loss, or even restore hearing after it has deteriorated.
A great deal of current research looking at treating age-related hearing loss has focused on restoring those sensory ear hair cells that line the inner ear. The most common hypothesis explaining the hearing loss that comes with old age is the degeneration of these ear hair cells.
But that isn’t the only hypothesis floating around …
Inside the cochlea is a structure called the stria vascularis. This structure plays a major role in our hearing and some researchers have long-suspected that age-related degeneration of the stria vascularis could influence hearing loss.
“It was hypothesized since the 1970s that the stria vascularis may play a role in hearing loss in humans, but the molecular evidence for this was missing until today,” said co-main author on the new study, Christopher Cederroth.
This new evidence comes from a meta-analysis encompassing 17 studies and more than 700,000 people. The researchers were looking for genetic links to hearing loss and they homed in on 48 significant variants associated with impairments, 10 of which were entirely new.
Most interestingly, many of the genes associated with hearing impairment are expressed in parts of a cochlea linked to the stria vascularis. This offers good evidence that this structure in the ear plays some part in age-related hearing loss.
The researchers are clear in stressing hearing loss is a deeply heterogeneous disorder and a huge array of different factors likely contribute to an individual’s hearing loss in old age. It’s thought genetics are responsible for anywhere from 36 to 70 percent of a person’s age-related hearing impairment, and environmental or lifestyle factors account for the rest.
So the study isn’t pointing to a single magic all-purpose cause of hearing loss in old age. Instead, it offers good evidence that degeneration of the stria vascularis plays a part, and this knowledge helps researchers define new targets for drugs or gene therapies that may prevent hearing loss in the future.
“Our findings identify 10 genes newly linked with hearing loss,” explained co-author Frances Williams. “This study points to genes we could target for screening purposes, drug development and even gene therapy in the future. This study provides a solid foundation for ultimately improving therapies against hearing loss.”
The new study was published in the American Journal of Human Genetics.
Source: King’s College London
