Home Genetic Testing is Convenient but it isn’t Complete & There are Some Issues
Home delivery for everything from fresh produce to custom-selected clothing has become a way of life for many Americans. While most home-delivery conveniences are generally changing our lives for the better — giving us more time and choices — at-home genetics kits that reveal information about the risk of developing certain cancers represent a risky step in our on-demand culture.
The FDA recently gave 23andMe the green light to sell the first direct-to-consumer tests for mutations in the BRCA1 and BRCA2 genes, which are linked to serious risks of developing cancer. All a buyer has to do is ship a saliva sample to the company. Six to eight weeks later, the results are delivered through an online portal.
Mutations in the BRCA1 and BRCA2 genes were initially linked to breast cancer, hence the names (“BReast” and “CAncer”). We now know that they also increase the risk of ovarian, prostate, and pancreatic cancer. Women with mutations are at least five times more likely than women without them to develop breast cancer, and up to 20 times more likely to develop ovarian cancer. Men with BRCA2 mutations are at much higher risk of developing an aggressive form of prostate cancer.
Learning you have a BRCA mutation can be life-altering for patients and for their family members, who may also carry the mutation. In my work as a medical oncologist specializing in the management of inherited cancer, I help individuals understand their cancer risks along with strategies for cancer prevention and early detection. For most people, this is a complex and stressful conversation.
The test for the BRCA1 and BRCA2 genes, from 23andMe assesses only three of the more than 1,000 known BRCA1/2 mutations, raising concerns that women who are told they do not have any of those variants will be lulled into believing that, as a result, they do not have an elevated risk for breast and ovarian cancer.
Genetic testing companies also sell your information to third parties. When you sign up for Ancestry or 23andMe, you probably didn’t read the fine print to find out what, exactly, those companies plan to do with your data. The company may claim ownership of the DNA sample you send them, and the analysis they run on it, including the resulting information on the makeup of your genome, the company can use that DNA basically however it wants:
When a BRCA1 or BRCA2 mutation is discovered early, the information can be lifesaving. Women ask me: Should I have my breasts removed and, if so, when? I know I need to have my ovaries removed, but I am worried about menopause, so how long can I wait? When do I tell the man I am dating that I have a BRCA mutation? Men ask me about their risk of prostate cancer. Almost everyone worries about passing the mutation along to their children.
In our clinic, we generally set aside an hour for the initial discussion, with additional discussions over time. The same is true in similar clinics across the country. This kind of discussion and explanation isn’t something you’ll get with your 23andMe results.
Over the past decade, researchers have made fundamental advances in our knowledge of inherited susceptibility to cancer. But there’s more to breast and ovarian cancer risk than BRCA1 and BRCA2. Genetic tests that I and other physicians order can evaluate up to 30 such genes. For most individuals with a strong personal or family history of cancer, insurance will cover the cost of tests a health care provider orders.
In contrast, the test available through 23andMe generates an incomplete picture (and you pay the full cost out of pocket).
A patient who came to my clinic in 2012 is an example. That was a year before the FDA warned 23andMe that it was marketing a diagnostic tool without approval, and highlighted the danger of the potential health consequences of false positive or false negative results. This patient — let’s call her Jane — told us about a very significant family history of cancer. Her sister died of ovarian cancer at 48, her mother at 62. Her maternal aunt was diagnosed with breast cancer at 49, and her maternal grandmother with colon cancer at 46. Jane had done testing through 23andMe and was under the impression that she was negative for BRCA1 and BRCA2 mutations.
Here are the problems:
Jane was not of Jewish descent. There are thousands of known mutations in the BRCA1 and BRCA2 genes. 23andMe tests for just three of them, and these three are commonly found among individuals of Ashkenazi Jewish descent. But the test is unlikely to be useful to those who are not of Ashkenazi descent; further analysis is needed. That means Jane may have a BRCA mutation even though 23andMe did not report one.
BRCA1 and BRCA2 are not the only cancer genes. Mutations in many other genes also increase the risk of breast and other cancers. These other genes are also important in understanding your risk. Families with Lynch syndrome, for example, have an increased risk of ovarian, colon, and uterine cancer due to non-BRCA genes. Based on Jane’s family history, she needed to be tested for this syndrome. Without including other genes, her testing would have been incomplete and not useful.
Family history matters. Even if Jane does not have a BRCA mutation, she still has a significant family history of cancer, which calls for enhanced screening and prevention strategies.
The best information is actionable. The best way to use genetic information to improve your health is to work with your health care team to interpret test results in the context of personal and family history.
Jane’s misunderstanding of her 23andMe results led her to underestimate her cancer risk. We tested her for 25 different cancer-related genes. She did not have a specific mutation in any of these genes. Even so, we recommended increased screening and prevention options on the basis of her strong family history. We also recommended that other members in her family be tested to see if we could identify the family’s specific genetic risk.
Genetic testing can be lifesaving, but it must come with all the facts — which are mounting by the day — and appropriate professional support to help individuals live and plan for the best chance of a healthy life, no matter what the results reveal. That’s something a mail-order kit just can’t do.
You may think it’s pretty remarkable that we can now test for genetic risk of developing certain diseases.
Genetic testing looks for mutations, or abnormalities, in our genes that help us understand if we’ve inherited a risk for particular health issues—and if we can pass along this risk to our children.
It now appears the impressive science of genetic testing is moving into our homes. In February 2015, the U.S. Food and Drug Administration (FDA) approved for the first time that a genetic test could be marketing directly to consumers.
For healthcare consumers, the FDA clearance means that you no longer need to see a doctor to learn about your risk for the rare Bloom syndrome, a rare syndrome characterized by short stature (usually under five feet), sun sensitivity, and an increased risk for cancer.
Supporters of the authorization from the FDA say that providing consumers this opportunity will provide benefit, allowing you to know more about your inherited risk for this condition—a potentially important concern for prospective or new parents.
The test cleared for direct-to-consumer marketing comes from the company 23andMe. It’s designed to identify healthy individuals who carry a gene that could cause Bloom syndrome in their children. The 23andMe test can determine if you’re a carrier for Bloom syndrome, meaning that you don’t have any symptoms of the disorder but might carry one copy of the abnormality and risk passing it on to your children. In Bloom syndrome, both parents need to carry the mutation and each pass it to their child for the child to develop the disorder.
Safe and correct use of this test is still very important. To make sure consumers get the information they need, the FDA requires 23andMe to provide adequate information in the label so that users will understand what the test means and how they can reach the right professionals (such as a board-certified geneticist) for counseling before and after testing.
To help ensure the quality of direct-to-consumer genetic tests, the FDA will require carrier-screening tests to adhere to general and special controls. Special controls can include performance standards, post-market surveillance, patient registries, and special labeling requirements and guidelines.
The makers of the Bloom syndrome test (23andMe) remind consumers that, even with thorough controls, genetic testing isn’t always 100 percent accurate. People who use the test should also work closely with their doctors and a board-certified geneticist.