The FDA has just approved 23andMe’s Personal Genomic Service (PGS) Pharmacogenetic Reports. This marks the first direct-to-consumer test for pharmacogenetics of enzyme variants that may affect the way patients break down medications. Consumers collect their saliva into 23andMe’s testing kit, mail it to the company’s labs, and then receive the results via an online portal. The approved pharmacogenetic assessment system looks for 33 variants of common enzymes that affect medication metabolism, including CYP2C19, CYP2C9, CYP3A5, UGT1A1, DPYD, TPMT, SLCO1B1, and CYP2D6. The full list of variants can be found here.

“This test is a step forward in making information about genetic variants available directly to consumers and better inform their discussions with their health care providers. We know that consumers are increasingly interested in genetic information to help make decisions about their health care,” said Tim Stenzel, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, in a press release.

These enzyme variants have important effects on how patients respond to drugs. For example, the enzyme CYP2C9 metabolizes the medication warfarin, a blood thinner with a narrow therapeutic range. Too much can cause internal bleeding and too little can be ineffective and allow blood clots to form. Knowing which variant of this enzyme a patient has should, theoretically, guide the treatment plan for that patient. Interestingly, three clinical trials of genotype-guided warfarin treatment showed that there was no difference between patients dosed by genotype and clinical guidance versus patients dosed only by clinical guidance (Pirmohamed 2013, Kimmel 2013, Gage 2017). Therefore, while this direct-to-consumer test provides good information about how a patient might respond to drugs, the data should be carefully reviewed by an experienced medical professional, and patients should not use the information to make their own treatment decisions. Furthermore, the FDA also recommends that healthcare providers must verify the results from this test with independent pharmacogenetic testing before making medical decisions.

This is the fourth direct-to-consumer test that 23andMe has gained marketing approval for. Other tests include genetic risk tests for Bloom syndrome, Parkinson’s disease, late-onset Alzheimer’s disease, celiac disease, alpha-1 antitrypsin deficiency, early-onset primary dystonia, Factor XI deficiency, Gaucher disease type 1, Glucose-6-Phosphate Dehydrogenase deficiency, hereditary hemochromatosis, hereditary thrombophilia, and BRCA-associated breast, ovarian, and prostate cancers.

The FDA has just issued a specific warning against the use of pharmacogenetic testing for treatment plans without definitive scientific evaluation and FDA approval.