Major study finds unique genetic change for severe eye disease
A new genetic risk factor for a severe eye disease that’s the leading cause of vision loss in over 50s has been uncovered. And the message is to get a scan to check for it, if you are in this age bracket.
A large international study led by Australian researchers has found a new genetic risk for developing a severe form of age-related macular degeneration (AMD), the leading cause of vision loss in people over 50.
The team says the discovery offers the potential for improved diagnosis and more targeted treatments for those with the eye disease.
AMD causes the death of light-sensing cells in the macula, the part of the retina needed for central vision.
Published today in Nature Communications, it was led by the Centre for Eye Research Australia (CERA), WEHI and the University of Melbourne.
Study co-lead Professor Robyn Guymer from CERA said the results showed AMD was not a single disease but a group of related conditions potentially requiring tailored treatments.
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“Age-related macular degeneration is devastating,” Professor Guymer said. “People can’t read, they can’t drive, recognise faces. And at the moment, while we are making great advances in treating the stage when you have already got a problem, we don’t know how to stop people getting AMD in the first place.”
She said understanding the initial causes may lead to better treatments earlier to stop people needing injections in their eyes, often forever, to reduce the end stage of the disease.
Professor Guymer said the surprising find was recognising that one particular genetic pathway - found on chromosome 1 - had no role to play in a high-risk group of patients and pointed to a more likely culprit on chromosome 10.
“Up until that point we had just thought that there were these two genetic pathways that were equally relevant to severe AMD, but this was very striking in that one of the pathways fell away completely,” she said.
The researchers said in its early stages it was difficult to predict who was at risk of vision loss and when treatment should begin, and that existing therapies only slow disease progression after significant damage has occurred.
For the first time they saw a key difference in genetic changes in the group with reticular pseudodrusen, which are deposits that drive vision loss and are found in the retina of up to 60 per cent of people with advanced AMD.
“We’ve made big advances in the treatment for slowing down the death of cells, but they’re all targeting the other pathway, the one that fell away,” Professor Guymer said. “The benefits are there, but modest. So we have to think of this other pathway, which we didn’t really before.”
She said next was to hone in on understanding the role of chromosome 10 and how it impacts the retina and look at developing individualised therapies.
“With much better imaging techniques of the eye, we can probably develop different treatments. At the moment, we just give everybody the same thing,” she said.
Professor Guymer said the message is if you’re over 50, it is a good idea to have your eyes checked.
“Reticular pseudodrusen deposits, visible in eye scans, have been linked to worse visual function and poorer treatment outcomes,’’ she said.
“Our research has now identified which of the genetic changes appear to be driving this more serious form of AMD. This discovery provides a crucial lead for developing new drugs that target these changes, potentially preventing vision loss before it begins.
“If possible have a scan of your eyes to look for these deposits because sometimes they’re missed, and then take the advice of an optometrist as to whether you should be referred on or whether you should be monitor more closely.”
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Originally published as Major study finds unique genetic change for severe eye disease
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