Can 23andme detect BRCA gene mutations? What to know before and after testing
Not only do home genetic test kits, like 23andMe, provide information about your ancestry, but they can also give you some insights into your inherited health risks, particularly mutations on the BRCA genes that can increase your chances of getting breast cancer down the line.
While most cases of breast and ovarian cancer aren’t hereditary, having certain BRCA mutations can significantly increase your risk for these cancers, the Centers for Disease Control and Prevention explain. In the general population, about seven in 100 women will develop breast cancer by the time they turn 70 compared to 50 out of 100 women who have BRCA1 or BRCA2 mutations, the CDC says.
One in every 500 women has a mutation on one of their BRCA genes. If either of a person’s parents have a BRCA mutation, then the person has a 50% chance of having the same one, per the CDC.
In 2018, 23andMe became the first company to get authorization from the Food and Drug Administration to provide BRCA genetic testing at home without a doctor’s referral ahead of time.
The test, which costs $199 and just requires a sample of your saliva, is an easy way to get a window into your potential health risks. But experts told TODAY that not everyone needs to follow their curiosity down this path — and it’s probably worth having a conversation with your doctor about your genetic health questions first.
If you’re thinking about using 23andMe to detect BRCA mutations, here’s what you should know.
What are BRCA gene mutations?
BRCA1 and BRCA2 are genes that typically help your body suppress cancerous tumors, the CDC explains. If you have certain changes — called variants or mutations — in your BRCA genes, that may affect your health risks. But not all genetic variants are inherently harmful.
“We all have little changes in our genes,” Dr. Alicia Latham, medical geneticist and family medicine physician at Memorial Sloan Kettering Cancer Center, told TODAY.
On one end of the spectrum, there are totally benign variants that are neither good nor bad and “may just create or contribute to our uniqueness,” Latham said. At the other end of the spectrum, there are true, pathogenic mutations that increase the risk for certain health conditions, like breast cancer.
In between, there are many variants of uncertain significance, which indicates that experts don’t know exactly what effect that mutation might have on your health risks, Dr. Banu Arun, professor of breast medical oncology and co-director of the Clinical Cancer Genetics Program at MD Anderson Cancer Center, told TODAY.
In fact, there are more than 1,000 possible mutations in just BRCA1 and BRCA2 that could affect cancer risk, Arun explained. Three of those mutations — known as founder mutations — significantly increase the risk for breast cancer, ovarian cancer and prostate cancer, according to the National Cancer Institute. And people with Ashkenazi Jewish heritage are particularly likely to carry these mutations, the CDC says.
These are the three mutations that 23andMe tests for, Ruth Tennen, Ph.D., senior product scientist at 23andMe, told TODAY. The company chose to focus on these because they are some of the most well-studied variants, she said.
But because there are many more possible BRCA variants out there that 23andMe does not detect, “we’re really just testing for a very small subset of those variants that are of particular importance for people of Ashkenazi Jewish descent,” Tennen explained.
Can 23andMe detect breast cancer?
Genetic tests like 23andMe can’t tell you whether or not you actively have cancer. Instead, 23andMe tests for specific BRCA1 and BRCA2 mutations that put you at a higher risk for developing certain types of cancer, including breast cancer.
Specifically, 23andMe looks for these three BRCA variants:
- BRCA1 185delAG
- BRCA1 5382insC
- BRCA2 6174delT
Remember that there are other BRCA variants that 23andMe does not test for that might also impact your breast cancer risk. “And, importantly, there are other genes out there that can increase the risk of hereditary breast cancer,” Arun said, such as mutations in PALB2, ATM, CHEK2, CDH1 and p53 genes.
Who should consider BRCA genetic testing?
If you’re interested in learning more about your BRCA status or your genetic risks for any health conditions, start by talking to your doctor or a genetic counselor, the National Cancer Institute says, which should include a discussion of your family’s health history.
In doing so, you may learn that you actually meet the eligibility requirements for comprehensive genetic testing ordered via a counselor or your doctor. For instance, Ashkenazi Jewish women who have a first-degree relative who was diagnosed with breast or ovarian cancer are likely to be eligible, the CDC says.
Another reason to meet with a counselor first is that at-home genetic testing may tell you about many more genetic results than just those related to BRCA, Latham said. “You may think, ‘Well, I want to know my BRCA status and that’s what I’m doing this for,’ but you may find a surprise that makes absolutely no sense based off of your family history and has very serious implications for you.”
If you test a lot of people for a lot of different genetic variants that they don’t necessarily need to be tested for, “we are increasing the risk of receiving results that we do not know what to do with,” Arun explained. “That increases anxiety amongst the patient and the healthcare provider.”
With a genetic counselor, you will only be tested for the genetic risks that make sense for you to investigate, Arun said. And you’ll have someone to help you sort through the results.
Related: At-home genetic testing for cancer and other disease risk is booming: Should you try it?
What should you do with your results?
Whether your BRCA results are positive or negative, you should go over them with your doctor. If your results are negative, that doesn’t mean you don’t have any of the many other BRCA mutations that can affect your cancer risk. And if your results are positive, you will likely need confirmatory testing to be sure.
Latham recommended consulting the National Society of Genetic Counselors database to find someone who specializes in the issues you’re particularly interested in.
Because 23andMe is only looking for a few BRCA variants, “if you get a negative result in these three specific mutations, you are not ruling anything out,” Arun said. “So you’re not done yet.”
Latham agreed, adding that, even if you get a positive result, a genetic counselor would likely recommend another round of testing to confirm.
“We really think about ourselves as a kind of screening test,” Tennen said, noting that 23andMe may reach people who don’t qualify for or can’t otherwise access clinical genetic testing.
The company provides comprehensive education about BRCA variants on its website, she noted. And consumers need to opt in multiple times throughout the process after being made aware of the limitations of 23andMe testing.
Once a consumer has their results, “we really try to emphasize that a negative result doesn’t mean you’re in the clear, and then if you have a positive result, you need to get confirmatory testing because we are not a diagnostic test,” Tennen said. Additionally, 23andMe recently acquired telehealth company Lemonaid Health, so the company can also provide genetic report consultations.
Still, Arun and Latham said they would encourage those who are interested in learning more about genetic testing to start with their doctor — not an at-home test.
“People are curious, that’s in our nature,” Latham said. But before going through genetic testing on their own, it’s important “to understand what the implications may be,” she continued. “And it’s not just implications for yourself — it’s implications for your family, too.”
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