In the UK, over-the-counter genetic tests that assess the risk of cancer or heart problems fail to identify 89% of people at risk of life-threatening diseases, a new study suggests.
Polygenic risk scores are so unreliable that they also falsely tell 1 in 20 people who receive them that they will develop severe disease, even if they don’t.
That’s the conclusion of an in-depth review of the performance of polygenic risk scores, which underpin tests on which consumers spend hundreds of dollars.
These findings come amid a rise in the number of companies offering polygenic risk score tests that purport to tell customers their likelihood of contracting a particular disease.
Everything Genetic promises that its Antegenes cancer test uses cutting-edge polygenic risk scoring technology to assess an individual’s genetic risk of developing cancer.
“The test will tell customers their personalized risk score of developing the tested cancer over the next 10 years, compared to other people in their age group,” their website claims.
But academics from University College London (UCL) who undertook the research warn that these tests are so flawed that they should be regulated “to protect the public from unrealistic expectations” to correctly identify their risk of contracting a disease. particular illness.
The authors concluded: “Polygenic risk scores performed poorly in population screening, individual risk prediction, and population risk stratification.
“Strong claims about the effect of polygenic risk scores on health care seem disproportionate to their performance. »
The scores are used to estimate a person’s risk of disease by analyzing whether genes identified by a blood test increase their chances of getting it.
Each gene that can contribute to the development of a disease is assigned a risk percentage. The risk percentages of all genes present in an individual that may contribute to the development of a certain disease are then added together to form an overall “polygenic risk score.”
However, Breast Cancer Now defended the tests. They can provide important information when used with details about a person’s medical history, for example, the association said.
“This research shows that polygenic risk score tests alone do not accurately predict breast cancer risk,” said Dr. Kotryna Temcinaite, research communications manager.
“We know that many different factors contribute to the risk of developing the disease, including family history and lifestyle. So when Combined with other ways to assess breast cancer risk, this type of test can add crucial information and lead to more reliable results.
The authors, led by Professor Aroon Hingorani from UCL’s Institute of Cardiovascular Sciences, looked at 926 polygenic risk scores for 310 diseases. They obtained details from the Polygenic Score Catalog, an open access database.
In highly critical findings, they found that on average only 11% of people who developed illness were identified by the tests, which also implied a “false positive” rate of 5%. The authors found that risk scores identified only 10% of people who developed breast cancer and 12% of those who developed coronary heart disease, and mistakenly told 5% of people that they would get sick when they did not. They ultimately weren’t.
The tests are not as reliable as cancer screening, for example, they said. “Strong claims have been made about the potential of polygenic risk scores in medicine, but our study shows that this is not justified.
“We found that, when held to the same standards used for other tests in medicine, polygenic risk scores performed poorly in predicting and screening for a range of common diseases.” Hingorani said.
Our Future Health, an NHS-backed medical research program that aims to recruit 5 million participants, uses polygenic risk scores in its quest to identify disease risk and encourage people to adopt healthier lifestyles.
Dr Raghib Ali, its chief medical officer, said: “This study rightly highlights that, for many conditions, genetic risk scores alone may be of limited utility, as other factors such as lack of , lifestyles and the environment are also important.
“(Our) research program will develop integrated risk scores that take into account all important risk factors.
“We hope that these integrated risk scores can identify people who are most likely to develop diseases, but this is a relatively new area of science and there are still unanswered questions.” »
Its 5 million volunteers will help it “discover whether these risk scores have a role to play in giving thousands of people the chance for longer, healthier lives,” Ali added.