NEW YORK — Experts have called for US Food and Drug Administration regulation of direct-to-consumer (DTC) tests that use a polygenic risk score (PRS) to estimate an individual's disease risk.
PRS are genome-wide measures of individuals' genetic propensities for diseases that, combined with other lifestyle factors, can give a better idea of how likely one is to get a specific condition.
In a Viewpoint commentary in the Journal of the American Medical Association on Thursday, Jacob Sherkow, a professor of medicine at Carle Illinois College of Medicine and professor of law at the University of Illinois at Urbana-Champaign College of Law, along with Jin Park and Christine Lu from Harvard Medical School, described concerns about poorly regulated DTC services that use PRS (which they abbreviate PGS) and their health impact on consumers.
While the FDA has the authority to regulate DTC products, one of the main reasons many PRS-based DTCs go unregulated is that they are marketed as general wellness products, which the FDA claims don't fall under its purview.
"This is problematic because the potential harms from these tests are much the same as those posed by traditional DTCs," the authors wrote in their commentary.
They noted concerns about consumers' misunderstanding of the tests' accuracy or utility, which could result in poor medical decisions. For instance, consumers might equate their PRSs to a clinical diagnosis or replace a validated, traditional diagnosis with a free, online PRS consultation. For example, they said, a consumer might rely on 23andMe's type 2 diabetes PRS risk report over a standard hemoglobin A1C test from a physician.
Despite the mounting concerns, the popularity of these tests has grown multifold in the last few years for several reasons. First, DNA samples have become relatively easy to collect. All a consumer has to do is self-swab a buccal sample and ship it to companies that can sequence the DNA from the cells. In cases where people already have DNA sequenced, they may choose to have it analyzed by companies or software by just uploading it online, said the authors.
PRS are even marketed as improvements on traditional single-nucleotide variant tests, which the FDA has over the years sporadically regulated. Newer tests now generally consist of the summation of risk scores of multiple, genome-wide, SNV risk variants for a particular condition.
According to the authors, some tests are laboratory-developed and as such should fall within the FDA's purview. Still, the fact that the companies combine PRS with other features of disease risk, such as diet, exercise, and lifestyle factors, to market them along the lines of general wellness tests, complicates the matter.
For example, the personality report from Adntro Genetics includes a PRS that assesses, among other behaviors, a "genetic predisposition to alcohol consumption" based on a 2019 study that measured alcohol dependence syndrome, a well-recognized health condition. This test, the authors wrote, would likely evade the FDA's scrutiny as it is marketed as a general wellness product.
Even software that provides genetic analyses escapes the FDA's regulation as the agency limits its oversight of software products for medical purposes such as diagnosis, prevention, and monitoring.
The authors said that given the harms of PRS misinterpretation and misuse, the FDA needs to actively police DTC-PRS in a similar way to how it regulates traditional DTC tests. They added that this would not require significantly revamping the FDA's statutory authority or policy shifts.
"As genomic sequencing and interpretation complexifies, improves, and becomes more akin to software than true laboratory-based tests, a nimble regulatory approach will be key to safeguarding the public health," they concluded.