What you should know about the potential unintended consequences of genetic testing

I recently talked with KevinMD on his podcast about the potential unintended consequences of genetic testing. You can learn more about the subject in this post.

Clinical and direct-to-consumer genetic testing are much less expensive and more common than they used to be. You can buy a genetic test kit at Walmart or your local pharmacy for under $200 and learn about your ethnicity and family tree, as well as your risk for certain diseases. More than 26 million people used at home DNA tests last year alone and that number is projected to grow. There are also clinical tests that can tell your doctor how you’ll respond to common medications such as blood thinners and antidepressants, determine whether you carry mutations related to certain types of cancer and other diseases, and assess the risk of passing a genetic disorder on to your children.

But before you take the plunge into your gene pool, there are a number of issues you should consider. Genetic testing can have unintended personal and medical consequences. That’s why it’s important to weigh the value of any information you may get from the test against the potential issues that the testing may raise.

How accurate are direct-to-consumer tests?

The accuracy and reliability of the testing is another concern, especially 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 as small as .01%.

False positive results for mutations linked to disease risk are another concern with direct-to-consumer tests. A study published in Nature 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, they can also lead to unneeded diagnostic tests, increasing health care costs.

What are the potential unintended consequences?

There are several potential unintended consequences you may face if you undergo any type of genetic testing:

• You have a mutation. What should you do? Even many clinical genetic tests cannot provide 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. Many tests are predictive, providing an estimate of the chances of developing a certain disease or condition. Tests also 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 manage your risk, for example, knowing you’re at a higher risk for a disease for which there currently is no effective treatment may only increase anxiety and stress.
• Your results may affect other people in your life. Learning your genes put you at an increased risk for a serious health problem can have an impact on other people in your family, including your siblings and children. You’ll need to think about whether you want to share your results with them since they may also be at risk. Some people may not want to know, especially when there is no current treatment for the disease, which can cause friction within your family.
• You may be at risk for genetic discrimination. Although there are federal and state laws designed to protect people with genetic mutations against discrimination by employers and health insurers, that protection isn’t guaranteed in all situations. For example, the federal Genetic Information Nondiscrimination Act doesn’t apply to employers with less than 15 employees or members of the U.S. military. The act also doesn’t apply to long-term care or life insurance providers, so you may be turned down for coverage or pay higher premiums.

Talk to your doctor first

If you decide to undergo genetic testing, your first step should be to 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 for you. 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 provide you with an expert interpretation of your results as well as recommendations for what you should include in your risk mitigation plan.