Both clinical and direct-to-consumer genetic testing have become significantly less costly and more common, providing people with access to a wealth of information about everything from their ethnicity and family lineage to their risk for certain diseases and how they will respond to medications such as blood thinners and antidepressants.
But before you decide to take the plunge into your gene pool, there are a number of issues you should carefully consider. Genetic testing can have unintended consequences, both personal and medical, so it’s wise to weigh the value of any information you may gain against the potential issues that the testing may raise.
In addition to the possible unintended consequences, you should consider the accuracy and reliability of the information the testing will provide. That’s especially important for people who choose direct-to-consumer genetic testing designed to provide an assessment of health risks. Compared to clinical genetic tests ordered by a physician and interpreted and communicated to you by an experienced geneticist, direct-to-consumer tests look at only a small portion of your DNA. In some cases, that portion can be as small as .01%, leaving large gaps in the information the test is able to provide.
False positives for mutations linked to disease risk are another important concern for users of direct-to-consumer tests. A Nature study discovered that 40% of the variants for several different genes in direct-to-consumer raw data were false positives. Not only can false positives cause a great deal of anxiety, but they can also lead the person to undergo diagnostic testing that is not, in fact, needed, increasing health care costs.
What are the potential unintended consequences?
Beyond the stories of people discovering through direct-to-consumer genetic testing that their father isn’t who they thought he was, there are several potential unintended consequences you may face if you undergo any type of genetic testing:
You have a mutation. Now what? Even many clinical genetic tests cannot provide you with a yes or no answer about whether you will eventually be diagnosed with a disease like breast cancer or Alzheimer’s or Parkinson’s disease. That’s because many tests are predictive, providing an estimate of the chances of developing a certain disease or condition. In addition, the tests cannot predict how severe your symptoms may be if you are eventually diagnosed with the disease.
While knowing you are at an increased risk for aggressive breast or ovarian cancer can help you, and your physician build a plan to mitigate your risk, for example, knowing you’re at a higher risk for a disease for which there currently is no effective treatment, such as Alzheimer’s disease or Huntington’s disease, may only increase anxiety.
Your results may impact other people. Learning you’re at an increased risk for a serious health problem due to a genetic mutation can not only affect you, but it can also have an impact on other people in your family, including your siblings and children. You’ll need to decide if you want to share the results of your testing with them since they may also be at an increased risk. Some people may not want this information, especially if it involves a disease for which there is currently no effective treatment. This can create friction within the family.
You may not be completely protected against genetic discrimination. Although there are federal and state laws designed to protect people with genetic mutations that may increase their risk of developing a disease from discrimination by employers and health insurers, that protection is not guaranteed in all situations. Case in point—the federal Genetic Information Nondiscrimination Act doesn’t apply to employers who have fewer than 15 employees or people who are members of the U.S. military. In addition, this act doesn’t apply to long-term care or life insurance providers, so you may be turned down for coverage or face higher premiums.
If you do decide to undergo genetic testing to assess your risk of developing cancer or other conditions, it’s wise to first talk with your doctor about your family’s medical history and get his or her input on what information genetic testing can and cannot provide in your specific situation. Rather than using a direct-to-consumer test, undergoing testing with the guidance of a genetic specialist can help you pinpoint the goal of your testing and will provide you with an expert interpretation of your results as well as recommendations for what you should include in your personal risk mitigation plan.
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