The popular gene testing company 23andMe this week received clearance from the FDA to market the first-ever direct-to-consumer test for select mutations to the BRCA gene, also known as the “breast cancer gene.” That may sound like a pretty big deal—but it turns out only a small group of people really stand to benefit from using the test.
The approved test will analyze three variants of the BRCA1 and BRCA2 gene, with a 99 percent reported accuracy. Carriers of BRCA mutations are known to have an increased risk of developing breast, ovarian, colon, prostate, and pancreatic cancer. The mutations are more common in Ashkenazi Jews and people of Norwegian, Dutch, and Icelandic heritage. Professional genetic testing for inherited cancer can be expensive, so an easy home test may be a desirable first step for many. The BRCA test is included in 23andMe’s “health and ancestry assessment package,” which costs $199.
The23andMe test has many limitations, however. The three BRCA1/2 variants for which the test is approved are commonly found in Ashkenazi Jews, but there are more than 1,000 BRCA variants. So even if an Ashkenazi Jew tests negative, it doesn’t rule out the possibility that other BRCA mutations may be present. So the test has a very limited application. Anyone who does test positive needs to consult a health care professional such as a doctor or genetic counselor, according to the FDA guidelines for using 23andMe.
Given the limited scope of the 23andMe analysis, it may make more sense to rely on family history—two or more close relatives who have developed breast, ovarian, colon, or prostate cancers—to determine the need for a BRCA test. If the family history indicates the need, you might want to seek professional testing with a genetic counselor, who can guide you through the process and help you assess risk.