Are Over-the-Counter Genetic Tests Risk-Free?
What everyone needs to know before trying 23andMe
Posted December 27, 2017
Over-the-counter genetic testing should come with a warning: “Use of this product can result in false assurances about your health risks. False negatives can lead to premature death.” For years I’ve wanted to beg the FDA to require this black box warning, but it was a courageous patient, Emily, whose experience with 23andMe last Christmas illustrated the urgency.
Over-the-counter genetic tests can be useful as a first step toward more comprehensive, professionally managed genetic analysis and testing that can help you understand your chances of developing one of any number of life-threatening diseases. But most OTC genetic testing companies, such as 23andMe, only test for specific markers along the genome. They do not sequence the whole gene, genome, or exome, which means they don’t uncover your full genetic profile. For example, these tests only sequence a few markers on the BRCA1/2 genes, so, even if you retrieve the raw data and analyze it with a geneticist, you’ll find the test misses the majority of mutations along the BRCA1/2 genes. The genetic risk factors for disease are complex, so by narrowing the focus to a few markers, OTC genetic testing companies are not assessing all of the anomalies that may increase your risk for disease. As a result, your test may indicate that you’re not at risk even when you are. Those who receive negative results will naturally be relieved, but if they want to take full control of their genetic destiny, they need to take another step forward.
Most people, however, don’t take this step, preferring to believe they’re in the clear. This is understandable. Finding out you’re at risk for developing a certain type of cancer or other degenerative disease can be devastating. But it’s also empowering. Knowing your real risk will allow you to take steps that could greatly reduce the chances you will get sick, and sharing your knowledge with your relatives will also empower them to protect themselves.
Emily, a newly married 28-year-old woman, took a 23andMe test last year and ultimately learned that she is at risk for hereditary breast and ovarian cancer. Her story serves as a disclaimer to anyone who is thinking of trying an OTC genetic test or who has already had one that showed they aren’t at risk. But her story also shows how a little perseverance and courage can help you find answers that could potentially save your life.
How and when did you discover you were at an increased risk of developing cancer?
Last Christmas my step-dad gifted my whole family 23andMe kits so we could compare with each other and learn more about our heritage. When I finally got the results, I found out that, although I’m mainly Ashkenazi Jewish (no surprise since my dad is Jewish and my mom is half-Jewish), I’m partially Yakut, Finnish, and Middle Eastern as well. Once we all had our results, I compared my results with those of my parents and my husband, and we had enormous fun competing over who had the most interesting heritage. I briefly looked over my health information, which showed nothing of concern, so I didn’t think twice about it. Plus, there were no diseases running in my family so I didn’t expect to find anything.
Six months later I learned about a third-party app called Promethease, which provides a more in-depth look at genetic data available from 23andMe. The additional information, although not FDA approved, ranges from gene mutations that have been proven to increase your risk of certain diseases as well as gene mutations that haven’t been well researched. I promptly paid my $5 fee and uploaded my data expecting to find small curiosities buried inside. I assumed if I had a disease-causing mutation it would have shown up in the 23andMe report so I was shocked to see, at the top of the page, a bright red box stating “BRCA1 variant considered pathogenic for breast cancer.” Below, it said I had up to an 87% life-time risk of developing breast cancer and a 40% chance of developing ovarian cancer.
What was your reaction?
Complete and all-consuming panic. It was like an out-of-body experience. I jumped out of my chair and paced around the kitchen sobbing. I could not cope with this sudden discovery. I couldn’t eat or sleep and cried on and off for the next two weeks. I spent so much time Googling I overheated my computer. I was convinced I could find research that meant the risks didn’t apply to me because of my lack of family history. I never did.
What did you do next?
Both my biological parents are geneticists, so I contacted them first. While I was still sitting in the table shaking with tears running down my face, I sent them a blank email with the subject line “I’m a BRCA1 carrier.” They both called me in under a minute. We quickly figured out the gene came from my dad’s side of the family since they both had taken the test, too. They were in complete shock and disbelief as well but reassured me that we would get through this. When my husband got home, I couldn’t get the words out to tell him and just showed him my computer.
My mom flew out to be with me that weekend and we tried to comfort each other, which really backfired when I wound up crying into some crab legs in the middle of a nice restaurant. When my mom left, she took a small DNA sample of mine with her to test in my dad’s lab. A little while later, my step-dad Mike sent me an email with the subject line “Forza,” which means strength in Italian. The body of the email read simply, “you will overcome this.” I repeat that to myself sometimes on difficult days.
Over the next month my family got in touch with any scientist friends whom we thought could help. I was overwhelmed with support and kindness from everyone I met. Relative strangers were willing to spend hours talking to me about my lack of family history, my personal risk, and my options. I was able to quickly get in to see a genetic counselor and provided yet another DNA sample for clinical testing.
How did the counselors and doctors help you?
In talking to so many people, I learned a lot about BRCA mutations and cancer risks. I discovered that there is a vast amount of variation in risk between families and between mutations. Some women who have these mutations have a risk close to 90% of developing breast cancer, while others have a risk of 30% that is much closer to that of the general population, which is 12%. The trouble is pinpointing any individual person’s exact risk. Everyone has a BRCA1 and a BRCA2 gene, located on chromosomes 17 and 13 respectively, which are anti-tumor crusaders. When our cells divide and replicate, these genes are busy at work repairing damaged DNA and errors that occur. When certain parts of this gene are mutated, that DNA is not repaired and can grow to become cancer. These mutations are rare. Only 1 in 300 people in the general population carries one of these mutations. However, some populations, like the Ashkenazi, have these mutations at a much higher frequency. Among the Ashkenazi, for instance, the rate is 1 in 40. Around half of those mutation carriers have no family history that would cause them to be tested, so they might not know they are at an elevated risk.
Many of the doctors I met had been diagnosed themselves (like you) with a BRCA mutation and were able to offer insight and advice no one else could. In talking with so many people, I realized I’d been hoping to find that one expert who could identify some part of my history that exempted me from the BRCA mutation risks. I never found that person. What I did find, however, was an enormous and supportive community of people: women, doctors, and researchers either going through the same thing, or who had family who were. Seeing so many people who have gone through the same thing and come out the other side living normal, fulfilling lives was the most helpful thing of all.
What did the clinical tests show?
Both my father’s test and the one done by my genetic counselor were positive for the mutation. Surprisingly, I didn’t panic or cry at the news. Although it’s counterintuitive, the uncertainty, with a mix of hope and fear, was far worse than simply having the knowledge. Knowing for sure that I had the gene was in some ways very empowering. I knew I had the faulty gene, and I knew that meant my risk of cancer was much higher than I’d assumed it was. But at least now I was armed with vast quantities of knowledge that I could use to tackle the problem.
What did you do with this information?
I learned that each mutation comes with its own risk. My specific mutation gives me a risk of breast cancer somewhere between 65% and 87%, although there is no way to know where in that range I am. That is not a risk I want to live with. I was offered two choices: have an MRI and a mammogram every six months for the rest of my life to screen for any signs of cancer, or have a preventative mastectomy and have my breasts reconstructed. I am picking the latter. I don’t want to spend the prime of my life having continuous screenings and living in a constant state of anxiety that today might be the day I find out I have cancer.
There is no good screening method to detect ovarian cancer, and it is often diagnosed late, which makes it difficult to treat. So as soon as I am old enough to go through surgical menopause without serious health risks, I will be removing my ovaries and fallopian tubes, too.
How has life changed since you found out your true risk?
Since taking the test I’ve felt constant anxiety over my body; it feels like a ticking time bomb. Some days I look in the mirror and feel a sense of gut-wrenching grief that my days with my body as I know it are limited. When I put on a shirt it’s hard to imagine that after this surgery I likely won’t feel the fabric touching my chest. At the same time, I know I’m making the right choice. Removing my breasts and ovaries seems extreme, but so is an astronomical chance of cancer. In having these surgeries I’m taking control of my body, my life, and my fears.
Would you recommend that everyone try an OTC gene-sequencing test?
The recent explosion of at-home gene testing is giving everyday people the power to gain extensive medical knowledge, but this knowledge also leads to profound uncertainty and anxiety. What happens when someone is blindsided by a cancer-causing mutation that requires surgical intervention (like I was) but has no support network or guidance? What happens when someone gets information that is much murkier and they can’t interpret the result? The internet is full of forums filled with confused and anxious people who discovered gene mutations but science and medicine simply don’t know yet if they are harmful or not. One friend discovered she has half a copy of a gene that causes Alzheimer’s disease and isn’t sure what to do with the information. If she had both copies, she would certainly get the disease at some point, but with only one copy, the chances are closer to 1 in 5. What is someone in that situation supposed to do other than worry?
At first I wished I had never done this test. The month after finding out was one of the darkest of my life. Finding out unexpectedly with no preparation or information was devastating and painful but could have saved my life. Being blindsided by cancer would have been so much worse.
Now that I’ve had more time to live with it, I realize this information is empowering. I’ve been given the closest thing to a premonition to see that a cancer diagnosis is very possible in my future, and I’ve been given tools to prevent it. Forza!
This piece was co-written with Emily Krauter.