If you’ve been reading the news, you know that last week the U.S. Food and Drug Administration approved the marketing of 23andMe Personal Genome Service Genetic Health Risk tests for 10 genetic diseases or conditions, including Alzheimer's, Parkinson's and celiac diseases. What you may not know is that these tests may provide incomplete, and potentially misleading, information about your risks for many of these diseases.
Genetic information has the potential to impact healthcare in a very significant way. It’s an important component of preventive medicine that can identify people who are at increased risk for a disease. As genetic counselors, we can then provide these individuals with prevention strategies that will help them to live a longer, healthier life. However, there are a multitude of genetic factors that influence the chance of developing a disease. These factors most often don’t act alone; rather, they act in conjunction with lifestyle choices, environmental factors, and even pure chance. In other words, it’s not that simple.
For some of the diseases on the 23andMe testing menu, the genes included in the test are only the tip of the iceberg. Testing for variations in these genes can’t predict whether you will or won’t get a certain disease; it can only provide an estimate of how your genetics influence your risk. In some cases, there may be stronger genetic factors that aren’t included in this particular test.
Because of this, some individuals may wish to seek guidance from an expert, like a genetic counselor, prior to and/or after undergoing this type of genetic testing. How do you know if you are one of these individuals?
Should you seek a genetic counselor for an at-home test?
The first clue is in your family history. Have any of your relatives had one of the diseases included in the list? If so, there may be genes to consider that aren’t among those tested by 23andMe. For example, APOE is the gene that’s included in the 23andMe panel. There is a specific version of the APOE gene called APOE4 that increases the risk of developing Alzheimer’s disease at an older age. But you can have APOE4 and not develop Alzheimer’s, and you can develop Alzheimer’s without having the gene. So, the results of an APOE4 test can be misleadingly reassuring or frightening. For this reason, and others, the American College of Medical Genetics and Genomics recommends against ordering APOE genetic testing as a predictive test for Alzheimer’s disease.
The genetic story behind Parkinson’s disease is equally complex with multiple genes implicated, some of which are more predictive than others. As with Alzheimer’s, the 23andMe panel does not include testing for all of the genes associated with this disease.
As you can see, your risk for the conditions measured by these tests depends on several factors, like family history, and things can get pretty complicated. Other questions you might want to ask yourself before undergoing direct-to-consumer genetic testing are:
- Would I be comfortable knowing that I’m likely to get a disease that I can’t do anything to prevent, and that can’t be cured or treated if I do get it?
- Am I ready to share what I learn with my relatives, since the genetic test results might also provide information about their health risks?
- Do I have concerns about other diseases NOT included in this particular genetic test?
I applaud consumers who want to take an active role in their healthcare and I agree that exploring your genetics is one important way to help you make wise decisions. Direct-to-consumer genetic testing is an exciting option and one that is likely here to stay. But genetic test results are empowering only if they are interpreted correctly. The National Society of Genetic Counselors believes that companies offering direct access to genetic testing have a responsibility to make it easy for consumers to find reliable resources including qualified genetics professionals, such as genetic counselors, to help interpret these results.
If you are considering direct-to-consumer genetic testing, or if you have received results and need further explanation, you can find a genetic counselor in your area or connect with one by phone by using NSGC’s Find a Genetic Counselor tool.
Mary Freivogel, MS, CGC, is a Past-President of the National Society of Genetic Counselors and a Senior Manager of Clinical Service Lines at Invision Sally Jobe Breast Centers.
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