Polygenic risk scores: Would you test to find out your risk of a disease?
Registered nurse and mother-of-three Anna Wilson, 45, now has regular colonoscopies and other screenings. Would you want to know your risk?
Conditions
Don't miss out on the headlines from Conditions. Followed categories will be added to My News.
Most Australians have never heard of polygenic risk scores — but once they do, many want one.
Polygenic risk scores (PRS) analyse the combined effects of multiple genes to predict a person’s likelihood of developing health conditions, such as cancers, heart disease, diabetes, and glaucoma.
When combined with environmental and medical history factors, they create a personalised health risk profile so patients can make better-informed choices around lifestyle, health checks and symptom awareness.
Just 11 per cent of Australians knew what these genetic tests were, when surveyed by Lonergan Research on behalf of News Corp in February.
But after learning more, nearly three-quarters said they would consider getting a test to assess their own health risks.
PRS is one of the major technologies being explored by the federal government, with a new national body focused on genomics launched on July 1.
Health Minister Mark Butler said Genomics Australia was the result of years of work from researchers, practitioners and government.
“This will put Australia at the forefront of genomic technology and research and delivering new hope for Australian patients with devastating diseases,” he said.
Alongside Genomics Australia’s launch, the government allocated $50 million to 30 projects via the Medical Research Future Fund – including multiple projects focused on PRS.
TESTING ALREADY AVAILABLE
Melbourne company Rhythm Biosciences already offers PRS to Australians who are curious about their personal risk of breast, colorectal, ovarian, prostate and pancreatic cancers; melanoma; atrial fibrillation; coronary artery disease and type 2 diabetes.
Individuals order a geneType test online to be supplied via their GP or a genetics counsellor then they provide a saliva sample which is used by the lab to calculate a PRS.
This is combined with factors such as age and family history to determine whether the individual is at average or increased risk of developing the condition within a defined time frame.
Rhythm Biosciences director of clinical and scientific affairs Dr Erika Spaeth described a polygenic risk score as a combination of genetic markers that act as little red flags spread across the genome each amounting to tiny proportions of risk.
“If you hold one small grain of rice and you drop it on the floor, it’s hard to find until you step on it,” she said. “That’s the amount of risk one of these markers has in your genome.
“We don’t care about one single marker, but when we can look at hundreds altogether, then you have a handful of rice. If you pour that on the floor, suddenly you see a pile and that becomes more meaningful.”
Dr Spaeth said there was “a lot of potential” for PRS in Australia and multiple groups working on ways to implement risk scores in a population setting.
“Right now we have this one-size-fits-all (approach to health screening) and our metric for deciding who is screened is really based on age as age is the primary risk factor,” she said.
She gave the example of everyone receiving a bowel test kit in the mail when they turn 50.
In an ideal world, Dr Spaeth would like everyone to understand polygenic risk and risk stratification, and for the geneType algorithm to be used for better allocation of healthcare resources.
“I would be very happy if someone went into their doctor’s office and it was just calculated in the back end,” she said.
“Then the doctors can say, ‘oh, I need these 10 per cent of my practice … to get a bowel screening kit five years earlier … but these 10 per cent don’t need their kit until they’re 60’.”
She would also like to see the geneType test – which currently costs $395 for a single condition test and $489 for a multitest – covered by insurance.
Registered nurse and mother-of-three Anna Wilson took the comprehensive geneType test, which she ordered through Genomic Health.
“You have to be your own advocate when it comes to your health,” Mrs Wilson, 45, said.
“I was flagged for colorectal cancer (at) moderate risk. I appreciate being aware of this as now I have more regular colonoscopies and other screenings to monitor any changes.”
South Australian company Seonix Bio also uses PRS to predict glaucoma risk, and has had significant uptake, with about 100 ophthalmologists and optometrists offering the SightScore test.
It can also now be ordered directly by individuals online, and recently became available in New Zealand and the US.
Co-founder and Professor of Ophthalmology at Flinders University Jamie Craig said the tests were so valuable because glaucoma is initially asymptomatic but early detection could minimise vision loss.
“(A person’s genetics are) massively significant as a predictor of disease,” he said.
SightScore currently shows people in the top 10 per cent risk category are 15 times more likely to develop glaucoma than those in the bottom 10 per cent.
But a new version of the test that is soon to be published presents a 100-fold difference in risk between the top and bottom groups.
“It’s extremely unique in medicine,” Prof Craig said.
“There’s nothing else in any other disease that is touching that at this stage.
“But it’s important not to overstate what it means as well because we’re at pains to point out to clinicians as we’re trying to educate that it’s not a diagnostic test.
“It’s not, ‘Oh, you are going to get glaucoma because your score was over 90’ or ‘you can never get glaucoma because you’ve got a low score’.”
SightScore costs $349-399 but the team hopes it will one day be covered by Medicare.
Sharon Taylor, 61, took a SightScore test as her mother had suffered from glaucoma since she was in her 30s and Ms Taylor wanted to be proactive about protecting her own vision.
She wears glasses and her optometrist had flagged that her eye pressure was increasing, but she had not noticed any symptoms herself.
“My risk score was 93 per cent so that’s a pretty high likelihood that I will develop glaucoma,” she said.
“If I didn’t need glasses for vision correction then I probably wouldn’t be doing anything about it.
“Glaucoma is very asymptomatic until it’s quite bad and you start losing vision so I guess that’s where SightScore comes in.”
She is now monitored every six months and joined a study run by Prof Craig that is exploring the use of laser treatment to lower eye pressure among patients with high polygenic risk even before vision loss begins.
YOUNG AUSTRALIANS LEAD THE CHARGE
The survey of more than 1000 Australians by Lonergan Research in February revealed just 11 per cent knew what a polygenic risk score was. The remainder either had not heard of it or believed they knew but chose an incorrect definition.
Awareness was significantly higher among younger Australians, with 17 per cent of Generation Z respondents (aged 18-29) choosing the correct definition, compared to 4 per cent of Baby Boomers (aged 65 plus).
Younger respondents were also much more open to finding out their own risk scores. Once told what PRS was, 83 per cent of Gen Z respondents and 85 per cent of Millennials (age 30-44) said they would consider getting a test – including a quarter of each who said they would definitely do it, whether the cost was government-subsidised or not.
This compared to 66 per cent of Generation X respondents (age 45-65) and 59 per cent of Baby Boomers.
Australia’s first Health Genomics Commissioner, Tiffany Boughtwood said there was a growing acceptance of genetic testing in general.
“It’s quite extraordinary the level of societal acceptability of genomic intervention and people are hungry to have this information to inform the choices they make about health care,” she said.
Genomic Health principal genetic counsellor Katrina Harrison – who offers the geneType test to clients across Australia in face-to-face and telehealth appointments – said preventive medicine was the future of healthcare.
“It’s definitely heading that way,” she said.
“Whole companies are emerging around personalised, preventive medicine.
“There is a myth out there that genetics is expensive but it’s just not true. People know they can’t put a price on health.”
Biggest transplant misconceptions exposed
A lack of knowledge about how many people need an organ transplant and fear of thinking about death has called for more awareness into how organ donation could be saving more lives.
Weight of dialysis: ex-AFLW star reveals kidney fight
She played footy at the top level and still runs her own gym — but for the past 18 months Richelle Cranston has had to make a huge life change ever since she found out her kidneys don’t work.