Scientists funded by the Royal National Institute for Deaf People (RNID), London, the national charity for deaf and hard of hearing people in the United Kingdom, have discovered a genetic link between exposure to loud noise and hearing loss.

The findings published in the July 2006 issue of Human Mutation identified three genes that influence the risk of developing noise-induced hearing loss, a condition that is irreversible. These genes play a role in recycling potassium in the inner ear—a process essential to normal hearing. 

Exposure to loud noise has long been known to cause hearing loss and is a leading occupational hazard in many countries. However, it has been less clear why some people are much more susceptible to noise damage than others. RNID funded this research at the University of Antwerp.

Professor Guy Van Camp, who led the research, says: “The project tested the hearing of 1,261 noise-exposed male workers from paper pulp mills and steel factories in Sweden. Genetic testing was then carried out on the 10% most susceptible and 10% most resistant workers. Seventy-nine percent of the people in this study had been exposed to noise for at least 20 years. Significant differences between susceptible and resistant workers were found in the sequence of 3 genes, KCNE1, KCNQ1 and KCNQ4.”

“Further studies on KCNE1 show the version of the gene associated with increased risk to noise causes the encoded ion channel to open more rapidly than the normal version,” he says. “This could affect the recycling of potassium making people with this version of the gene more sensitive to noise.”

Ralph Holme, RNID’s biomedical research manager says: “This is a very exciting breakthrough. One million people in the UK alone are at risk of developing noise-induced hearing loss. This discovery could revolutionize the way this common form of hearing loss is prevented and treated in the future.”

[SOURCE: RNID, July 5, 2006]