For the first time, the FDA gave DNA-testing company 23andMe authorization to market direct-to-consumer (DTC) genetic health risk (GHR) tests that provide information on an individual’s genetic predisposition to certain medical diseases or conditions. However, in announcing the approval, the FDA cautioned consumers to remember that GHR tests cannot predict the likelihood of developing a disease or condition, which depends on many factors beyond genetics.
23andMe’s GHR tests work by testing a saliva sample, isolating DNA from that sample, and testing it against 50,000 genetic variants. Certain variants are associated with an increased risk for developing certain genetic conditions. The GHR tests approved by the FDA are associated with:
- Parkinson’s disease, a nervous system disorder impacting movement;
- Late-onset Alzheimer’s disease, a progressive brain disorder that destroys memory and thinking skills;
- Celiac disease, a disorder resulting in the inability to digest gluten;
- Alpha-1 antitrypsin deficiency, a disorder that raises the risk of lung and liver disease;
- Early-onset primary dystonia, a movement disorder involving involuntary muscle contractions and other uncontrolled movements;
- Factor XI deficiency, a blood clotting disorder;
- Gaucher disease type 1, an organ and tissue disorder;
- Glucose-6-Phosphate Dehydrogenase deficiency, also known as G6PD, a red blood cell condition;
- Hereditary hemochromatosis, an iron overload disorder; and
- Hereditary thrombophilia, a blood clot disorder.
The 23andMe GHR tests were reviewed by the FDA through the de novo premarket review pathway, but in the future, the agency will exempt 23andMe from premarket review for additional related GHR tests, while other companies will also have the opportunity for an exemption after their first GHR tests receive premarket approval. However, this exemption does not apply to GHR tests that function as diagnostic tests, which are often used as the sole basis for major treatment decisions.
In 2013, the FDA issued a warning letter to 23andMe requiring the company to immediately halt marketing for their DNA testing kits until it secured FDA premarket approval. At that time, the FDA noted that 23andMe failed to complete studies that could validate the effectiveness of the DNA test kits and failed to provide additional information requested by the agency (see Citing Risks of Illness, Injury, or Death, FDA Orders 23andMe, Inc. to Stop Marketing DNA Test Kits, December 5, 2013). For this new approval, 23andMe submitted supporting data from peer-reviewed, scientific literature that demonstrated a link between specific genetic variants and each of the 10 health conditions. The FDA also reviewed studies, which demonstrated that 23andMe GHR tests correctly and consistently identified variants associated with the 10 indicated conditions or diseases from a saliva sample.
Risks associated with use of the 23andMe GHR tests include false findings, both false positives indicating incorrectly that an individual has a certain genetic variant, and false negatives indicating incorrectly that he or she does not have a certain genetic variant.
