The ability to test for glaucoma and predict a person’s risk of the disease will be significantly improved following the discovery of 40 new genetic markers by Australian researchers at QIMR Berghofer Medical Research Institute.
The genome-wide study of more than 134,000 people found 101 genetic markers that influence intraocular pressure (IOP), 40 of which also increased a person’s risk of glaucoma.
Associate Professor Stuart MacGregor, head of QIMR Berghofer Medical Research Institute’s Statistical Genetics laboratory, said the study found individuals with a large number of the genetic markers had an almost six-fold increased risk of developing glaucoma compared to someone who had fewer genetic variants.
the findings dramatically increased the current understanding of which genes caused glaucoma and high eye pressure
“The discovery of these previously unknown genetic markers for glaucoma will be important for improving our ability to test for and predict a person’s risk of the disease,” Associate Professor MacGregor said.
“Although a predictive test for glaucoma is not available yet, our discovery is very promising.
“If we can identify who is most at risk of developing glaucoma at the earliest opportunity, we can make sure those individuals receive the preventative treatment they need to stop them from going blind as they age.
“Early treatment is vital because once a person experiences vision loss, it is impossible to reverse.”
The study was done in collaboration with multiple clinicians, hospitals and institutions across Australia and New Zealand, including the Menzies Institute for Medical Research and Flinders University.
A/Prof. MacGregor said a person’s risk of developing glaucoma – which damages the optic nerve and leads to a gradual loss of the peripheral vision – increased with age.
The Director of the Flinders Centre for Opthalmology, Eye and Vision Research, Professor Jamie Craig, said the findings dramatically increased the current understanding of which genes caused glaucoma and high eye pressure.
“We expect far-reaching consequences in terms of predicting who will develop glaucoma in the population, and exciting possibilities to develop better ways to treat this disease, which is a leading cause of blindness worldwide,” he said.
“We have used DNA from thousands of patients with glaucoma to understand how these new genetic discoveries about eye pressure influence the risk of an individual developing severe vision loss from glaucoma.
“We are getting much better at predicting these outcomes in patients and this will help us find people at risk and get them on sight-saving treatment early in the course of the disease.”
Surprising Number of Variants
Associate Professor MacGregor said while the findings increased the number of known genetic markers underpinning intraocular pressure by more than 90, the most surprising finding was the sheer number of those variants that were associated with developing glaucoma.
“There is natural variation in eye pressure from person to person, and having high eye pressure doesn’t necessarily damage your vision,” he said.
“So for the 101 genetic markers we identified, although they are a risk factor, their presence in your genetic coding doesn’t necessarily mean you will develop glaucoma.
“However, we were able to show 53 of the genetic markers do directly increase your risk of developing glaucoma and particularly increase the risk of developing advanced glaucoma, the type that tends to cause blindness.”
A/Prof. MacGregor said the study, which has been published in Nature Genetics, used the genetic information of participants from the UK Biobank and the International Glaucoma Genetic Consortium.
Glaucoma affects approximately 300,000 Australians and is the leading cause of irreversible blindness worldwide. Although there is currently no cure, early detection through screening can halt or significantly slow the disease’s progression.
A/Prof. MacGregor’s research was supported by grants from the National Health and Medical Research Council and the Ophthalmic Research Institute of Australia, the BrightFocus Foundation.