The genetics of noise-induced deafness


Researchers from the University of California, San Francisco recently found that the lack of a specific gene may be related to loss of inner and outer hair cells, and that an experimental drug can prevent this inner ear damage, thus protecting hearing.

The gene of interest is Tmtc4 located at chromosomal location 13q32.3 in humans. The researchers looked at this gene in a mouse model and found that it plays an essential role in noise-induced deafness.

“It doesn’t take very long for hair cells to die and for the cochlea to basically become a scar – the whole structure of the cochlea changes,” said Dylan Chan, MD, PhD, in a university press release. He is an assistant professor of otolaryngology at UCSF and co-senior author on the research paper published in the Journal of Clinical Investigation. He added: “To restore hearing would not only require getting hair cells to regenerate, but also reproducing this finely tuned mechanical structure. The better option is to try and prevent the death of hair cells in the first place.”

It was found that the loss of Tmtc4 in cochlear hair cells distorted the cell’s calcium balance, leading to apoptosis at the cellular level and deafness physiologically. Importantly, the research team were able to use a compound called ISRIB, found by a fellow researcher, to stop the cell death process. Giving mice ISRIB before the exposure to loud noise prevented hair cell damage and noise-induced hearing loss.

In time, the findings may be useful in helping to prevent hearing loss in humans and perhaps even in the treatment of other types of cell-related hearing loss, such as age-related deafness.

Source: UCSF