On March 6, 2018, the U.S. Food and Drug Administration (FDA) authorized the Personal Genomic Service Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants), made by the company 23andMe. The test is sold directly to consumers and does not require a doctor’s authorization.
The test can identify three specific BRCA mutations that are most common in people of Ashkenazi Jewish descent. Still, it’s important to know that these three mutations are NOT the most common BRCA1/BRCA2 mutations in the general population.
The 23andMe test does not identify any of the other more than 1,000 known BRCA mutations.
About 5% to 10% of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child.
Genes are particles in cells, contained in chromosomes, and made of DNA (deoxyribonucleic acid). DNA contains the instructions for building proteins. And proteins control the structure and function of all the cells that make up your body.
Many inherited cases of breast cancer are associated with two genetic mutations: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two). But changes in other genes also are linked to breast cancer.
“This test provides information to certain individuals who may be at increased breast, ovarian, or prostate cancer risk and who might not otherwise get genetic screening and is a step forward in the availability of direct-to-consumer genetic tests. But it has a lot of caveats,” Donald St. Pierre, of the FDA’s Center for Devices and Radiological Health, said in a statement announcing the authorization. “While the detection of a BRCA mutation on this test does indicate an increased risk, only a small percentage of Americans carry one of these three mutations, and most BRCA mutations that increase an individual’s risk are not detected by this test. The test should not be used as a substitute for seeing your doctor for cancer screenings or counseling on genetic and lifestyle factors that can increase or decrease cancer risk.”
To use the test, a person collects a saliva sample in a container that comes with the test. The test kit is then sent to the 23andMe lab for analysis. Test results are sent back to the person as a report. Genetic counseling is not included with the test.
The FDA statement emphasized that the 23andMe test should not be used to make any decisions about preventive treatments or surgeries.
The three mutations detected by the test occur in about 2% of Ashkenazi Jewish women but are found in only 0% to 0.1% of the general population.
The FDA statement also emphasized that negative 23andMe test results do not rule out the possibility that a person has a higher risk of cancer associated with other genetic mutations, including BRCA and non-BRCA mutations.
“I think it’s really important to let consumers know that this test is only testing the three most common mutations in Ashkenazi Jewish families,” explained Cristina Nixon, a licensed certified genetic counselor with the Cancer Risk Assessment and Genetics Program at Main Line Health and member of the Breastcancer.org Professional Advisory Board. “So, in many cases, it is an incomplete test. Without involving a genetic counselor, physician, or other healthcare provider, the information may be very distressing or falsely reassuring.”
For more information on testing for genetic mutations linked to breast cancer, types of genetic tests, and how results are reported, visit the Breastcancer.org Genetic Testing pages.
Want expert insights? Hear licensed certified genetic counselor Cristina Nixon explain the benefits and drawbacks of at-home genetic tests, including the 23andMe BRCA test, in a Breastcancer.org podcast.