Hope for millions with hearing loss as scientists find 44 genes linked to age-related deafness in a discovery that could lead to a cure
- British researchers looked at genetic data of more than 250,000 participants
- They identified 44 genes linked to loss of hearing in people over the age of 40
- By age of 65, 40% of Britons are affected by hearing loss to varying degrees.
Scientists have identified more than 40 genes which they say could hold the key to curing deafness in old age.
British researchers found 44 strands of DNA were linked to loss of hearing in people over 40 after analysing genetic data from more than 250,000 participants.
They say the breakthrough could pave the way for treatments and a clearer understanding of how deafness develops over time.
By the age of 65, 40 per cent of Britons are affected by hearing loss to varying degrees.
The condition can lead to social isolation and disability and has been identified as a risk factor for dementia.
Scientists have identified more than 40 genes which they say could hold the key to curing deafness in old age (file image)
Despite being so common, little is known about its causes and the only treatment option available is hearing aids which are often not worn once prescribed.
The research team, from King’s College London and UCL, looked at genetic data of 250,000 participants of the UK Biobank aged between 40 and 70.
Volunteers were asked to fill out questionnaires on whether they suffered from hearing loss or if they wore a hearing aid.
A third of participants said they struggled with some form of age-related deafness.
Researchers then analysed their genetic data and found 44 genes were linked to hearing loss.
The genes were linked by studying 9million genetic variants and seeing if they differ in those with hearing loss compared to those without. Thirty of the genes had not been previously linked to hearing loss.
WHAT IS AGE-RELATED DEAFNESS?
Age is the biggest single cause of hearing loss.
Hearing loss that develops as a result of getting older is often known as age-related hearing loss or presbycusis.
It is caused by the natural aging of the auditory system – but scientists don’t know exactly how, or why.
Most people begin to lose a small amount of their hearing from around 40 years of age.
This hearing loss increases as you get older.
It affects around 40 per cent of Britons over the age of 65.
By the age of 80, most people have significant hearing problems.
As your hearing starts to deteriorate, high-frequency sounds, such as female or children’s voices, may become difficult to hear.
It may also be harder to hear consonants such as ‘s’, ‘f’ and ‘th’.
This can make understanding speech in background noise very difficult.
Another common cause of hearing loss is damage to the ear from repeated exposure to loud noises over time.
This is known as noise-induced hearing loss, and it occurs when the sensitive hair cells inside the cochlea become damaged.
It usually happens gradually as we get older.
The research team said this will lead to new pathways in biology that weren’t previously thought important in hearing.
Once the have the pathways, treatments can follow, according to lead author Professor Frances Williams.
Professor Williams, from the Department of Twin Research & genetic epidemiology at King’s College London said: ‘We now know that very many genes are involved in the loss of hearing as we age.
‘This study has identified a few genes that we already know cause deafness in children, but it has also revealed lots of additional novel genes which point to new biological pathways in hearing.’
Co-author Dr Sally Dawson, from UCL’s Ear Institute, hailed the findings and said they could lead to new therapies for millions around the world.
She added: ‘Before our study, only five genes had been identified as predictors of age-related hearing loss, so our findings herald a nine-fold increase in independent genetic markers.
‘We hope that our findings will help drive forward research into much-needed new therapies for the millions of people worldwide affected by hearing loss as they age.’
Dr Ralph Holme, executive director of research at Action on Hearing Loss, said: ‘These findings are incredibly significant.
‘We believe they will speed up the discovery of treatments to slow or even halt the progressive loss of hearing as we get older, something which happens to at least 70 per cent of over-70-year-olds.
‘This research was funded by us thanks to the generosity of our supporters and we know from people with hearing loss that being able to hear well again would completely transform their lives.
‘The identification of these genes linked to age-related hearing loss throws open the door to many new lines of research into treatments.’
Hearing loss is the result of sound signals not reaching the brain. There are two main types of hearing loss, depending on where the problem lies.
Sensorineural hearing loss is caused by damage to the sensitive hair cells inside the inner ear or damage to the auditory nerve, which occurs naturally with age.
Whereas conductive hearing loss occurs when sounds are unable to pass from your outer ear to your inner ear.
This is usually caused by a blockage such as earwax, a build-up of fluid from an ear infection, or because of a perforated ear drum or disorder of the hearing bones.
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