Age-related hearing loss may be genetic

Aug 28 2006

Researchers at the University of Antwerp have discovered that hearing loss is linked to flaws in a specific gene.

Hearing loss is very common in the elderly and millions of people have age-related hearing loss which is often linked to long term noise exposure.

It makes it difficult for elderly people to communicate with friends and family, and can lead to them feeling increasingly isolated.

Currently, little else can be done other than the provision of hearing aids and that does not prevent any further deterioration of the hearing ability.

The Dutch research team carried out a large study of 1,200 people ranging in age from 40 to 80 and found that minor changes in a gene called KCNQ4 increases the risk for hearing loss.

The researchers tested people's hearing and then looked at their DNA and found that three variations, single letter differences in DNA called single-nucleotide polymorphisms (SNPs), were seen in people with hearing loss but not in those with normal hearing.

They found that 37 percent of people ages 61 to 70, and 60 percent of those aged 71 to 80, suffered from age-related hearing loss.

In people with normal hearing, it is expressed in the hair cells of the cochlea where it helps recycle potassium, brought in to trigger a nerve signal to be sent to the brain, back into inner ear fluid.

They suggest possible explanations which include a build up of potassium in hair cells, or the too sudden removal of potassium.

Unfortunately regardless of the research findings, there remains no way of identifying those at risk for hearing loss or for preventing it.

The Royal National Institute for Deaf People which funded the work, says the research does provide hope for the treatment of hearing loss and also provides another important piece of the jigsaw in highlighting a gene associated with age-related hearing loss.

The researchers say more work is now needed to identify what effect these genetic spelling mistakes have.