University College London Study Shows Direct-to-Consumer DNA Tests Not Reliable in Assessing Disease Risk
Regulatory agencies in UK and US have yet to address dangers inherent in customer misunderstanding of DTC medical laboratory genetic test results
Direct-to-consumer (DTC) medical laboratory genetic tests are gaining popularity across the globe. But recent research out of the United Kingdom questions the reliability of these tests. The study, according to The Guardian, found that “Over the counter genetic tests in the UK that assess the risk of cancer or heart problems fail to identify 89% of those in danger of getting killer diseases.”
Researchers at University College London (UCL) examined 926 polygenic scores for risk of 310 different diseases from details retrieved from the Polygenic Score (PGS) Catalog. This catalog is an open-access database of published polygenic scores.
According the PGS website, “each PGS in the catalog is consistently annotated with relevant metadata; including scoring files (variants, effect alleles/weights), annotations of how the PGS was developed and applied, and evaluations of their predictive performance.”
However, the researchers told The Guardian, “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 healthcare seem to be disproportionate to their performance.”
The UCL researchers published their findings in the journal BMJ Medicine titled, “Performance of Polygenic Risk Scores in Screening, Prediction, and Risk Stratification: Secondary Analysis of Data in the Polygenic Source Catalog.”
“Strong claims have been made about the potential of polygenic risk scores in medicine, but our study shows that this is not justified,” Aroon Hingorani, PhD (above), Professor of Genetic Epidemiology at UCL and lead author of the study, told The Guardian. “We found that, when held to the same standards as employed for other tests in medicine, polygenic risk scores performed poorly for prediction and screening across a range of common diseases.” Consumer misunderstanding of DTC medical laboratory genetic tests is a real danger. (Photo copyright: University College London.)
Polygenic Scores Not Beneficial to Cancer Screening
To complete their study, the UCL researchers compared PGS genetic risk data to conventional clinical laboratory testing methods and discovered some troubling results. They include:
- On average, only 11% of individuals who developed a disease had been identified by the tests.
- A 5% false positive rate where people were informed that they would get a disease within 10 years but did not.
- PGS only identified 10% of people who later developed breast cancer.
- PGS only identified 12% of individuals who later developed coronary artery disease.
The researchers state in their BMJ Medicine paper that polygenic risk scores are not the same as testing for certain gene mutations, which could be critical in screening for some cancers. They also wrote that discovering genetic variants associated with the risk for disease is still crucial for drug development.
“It has been suggested that polygenic risk scores could be introduced early on to help prevent breast cancer and heart disease but, in the examples we looked at, we found that the scores contributed little, if any, health benefit while adding cost and complexity,” research physician and epidemiologist Sir Nicholas Wald, FRS, FRCP, FMedSci, Professor of Preventive Medicine at UCL Institute of Health Informatics and co-author of the study, told the Jersey Evening Post.
“Our results build on evidence that indicates that polygenic risk scores do not have a role in public health screening programs,” Wald added.
“This research study rightly highlights that for many health conditions genetic risk scores alone may have limited usefulness, because other factors such as deprivation, lifestyles, and environment are also important,” clinical epidemiologist Raghib Ali, MD, CEO, Chief Investigator and Chief Medical Officer, Our Future Health UK, told The Guardian.
Our Future Health is a collaboration between public, non-profit, and private sectors to create the UK’s largest health research program. The researchers in this endeavor intend to recruit over five million volunteers and use polygenic risk scores to develop innovative ways to prevent, detect, and treat disease. This program is funded by the UK’s National Health System (NHS).
“[Our] research program will be developing integrated risk scores that will take in all the important risk factors,” Ali explained. “We hope these integrated risk scores can identify people more likely to develop diseases, but this is a relatively new area of science and there are still unanswered questions around it.”
Danger of Misunderstanding DTC Genetic Tests
Here in the US, there have been news stories in recent years about the unreliability of certain genetic tests. Dark Daily covered these stories in previous ebriefs. News stories about the unreliability of genetic tests, particularly those marketed directly to consumers, reveal the problems that existing regulatory schemes have yet to address.
In “Consumer Reports Identifies ‘Potential Pitfalls’ of Direct-to-Consumer Genetic Tests,” we covered CR’s findings that though clinical laboratory and pathology professionals understand the difference between a doctor-ordered genetic health risk (GHR) test and a direct-to-consumer (DTC) genetic test, the typical genetic test customer may not. And that, misunderstanding the results of a DTC at-home genetic test can lead to confusion, loss of privacy, and potential harm.
Scientific American also covered the dangers of DTC testing in “The Problem with Direct-to-Consumer Genetic Tests,” in which the author notes that “despite caveats in ads and on packages, users can fail to understand their limitations,” and that “consumer-grade products are easily misconstrued as appropriate medical tests and create false reassurances in patients who could be at legitimate risk.”
Most clinical laboratory managers and pathologists are probably not surprised that the research performed at UCL shows that there are still issues surrounding genetic tests, particularly those marketed directly to consumers. While direct-to-consumer DNA tests can have some benefits, at this time, they are not always the best option for individuals seeking information about their personal risk for hereditary diseases.
—JP Schlingman
Related Information:
Over the Counter Genetic Tests in UK ‘Fail to Identify 89%’ of Those at Serious Risk
3 Things to Know about At-home DNA Testing Kits
What Can At-home Genetic Tests Tell Me about My Health?
What are the Benefits and Risks of Direct-to-consumer Genetic Testing?
Genetic Risk Scores ‘Do Not Have a Place in Public Health Screening’
Consumer Reports Identifies ‘Potential Pitfalls’ of Direct-to-Consumer Genetic Tests
