DNA test to spot cancer genes gets OK from U.S. regulator, but with warnings

Genetic testing company 23andMe won U.S. Food and Drug Administration approval to sell genetic tests for three key breast cancer mutations directly to consumers.

Test can only detect 3 out of more than 1,000 known inherited BRCA gene mutations

The FDA approved a direct-to-consumer breast cancer gene test that analyzes DNA from saliva. (CBC)

U.S. regulators have approved the first direct-to-consumer breast cancer gene test.

But the U.S. Food and Drug Administration said Tuesday it will require warnings about the limitations of the genetic information from California-based 23andMe.

The test, which analyzes DNA from saliva, can only detect three out of more than 1,000 known inherited BRCA gene mutations. It cannot determine a person's overall risk of developing cancer.

The FDA says the test is not a substitute for regular medical checkups and should not be used to make any medical decisions. Most cancers are not caused by genetic mutations, and the ones tracked by the test aren't the most common BRCA mutations.

Donald St. Pierre of the FDA's Office of In Vitro Diagnostics and Radiological Health said in a statement announcing the approval that the test is intended for people who might not otherwise get genetic testing, adding that "it has a lot of caveats."
 
Only a small percentage of Americans carry one of the three mutations, and most of the 1,000 known BRCA mutations that increase an individual's cancer risk are not included in the test. The test should not be used as a substitute for regular cancer screenings, he said.
 
The FDA also cautioned against using the results to make treatment decisions, such as anti-hormone therapies or the surgical removal of the breast or ovaries. Those decisions should be based on confirmatory tests and genetic counselling.
 
And FDA warned that the tests, which work by analyzing saliva samples, carry significant risks for individuals if they are used without consulting a doctor or genetic counselor.
 
The regulator said it reviewed data for the company's test under a pathway for low-to-moderate risk devices that are not equivalent to an already marketed device. The agency also outlined special controls designed to assure test's accuracy and reliability.
 
To win approval, the company submitted data showing its instructions and reports are easy to understand. They provide information on what the results might mean and where to get additional information.

The FDA blocked 23andMe from offering genetic health information in 2013. The company has gradually won clearance to reintroduce some testing services.

With files from Reuters