FDA officials are sending mixed messages about a genetic test they just approved -- and the lack of clarity could jeopardize Americans' health.
The test, from genomics firm 23andMe, is simple to use. Folks order it online and mail in their saliva samples. Within weeks, 23andMe analyzes their DNA for nearly three dozen genetic variants. Those variants can help predict how consumers would metabolize commonly prescribed drugs such as antidepressants and blood thinners.
FDA officials lauded the test as a "step forward" that will help patients "better inform their discussions with their health care providers."
Yet the FDA also issued an extensive list of warnings. The test "does not determine whether a medication is appropriate for a patient." As a result, "consumers should not use this test to make treatment decisions on their own. Any medical decisions should be made only after discussing the results with a licensed health care provider."
Inevitably, some consumers won't consult doctors and will stop taking certain medicines based on the results. It's irresponsible for the FDA to approve a product so prone to misuse, especially since the test results only make sense when contextualized by physicians.
This is hardly the first time that regulators have offered a stamp of approval to products consumers don't understand.
Consider FDA-approved breast and ovarian cancer diagnostic tests. These tests identify mutations within two genes associated with an increased risk for hereditary breast and ovarian cancer. Thousands of women have taken such tests.
Traditionally, patients had to order them through their doctors, who could contextualize the results. But in 2018, the FDA greenlit the first direct-to-consumer cancer test, also made by 23andMe.
23andMe's test searches for just three out of more than 1,000 known mutations on the two cancer-linked genes. Doctor-ordered tests, by contrast, are far more comprehensive.
Consider the experience of Jane -- a patient with a family history of cancer. After testing negative for three BRCA mutations through 23andMe's test, she believed she was in the clear. But the test failed to take into account her family history or thousands of other known mutations common to her descent.
Christine Stanislaw, director of genetic counseling at the Winship Cancer Institute of Emory University, warned that direct-to-consumer tests are generally "less likely to be able to predict your chances of developing a health problem."
Consumers may opt for direct-to-consumer tests without fully understanding their shortcomings. For instance, if a patient's test results don't show any of the three harmful genetic variants in 23andMe's test, she might think she isn't predisposed to breast cancer. Unaware that there are hundreds of other mutations, the patient might forgo regular preventative care and early-detection measures. This would make it harder to catch and treat cancer -- a life-or-death matter.
The FDA is widely viewed as the world's premier safety regulator. So when consumers see that a test is "FDA-approved," they assume it's high-quality. Increasingly, that's not the case.
The agency can protect consumers by refusing to approve products that could be easily misused and being clearer about the nature of the products it does approve.
Razib Khan is a geneticist who serves as the Director of Scientific Content at Insitome. He also co-hosts "The Insight," a podcast that uses scientific tools to explore human history, and blogs at Gene Expression (gnxp.com).
By Razib Khan.
