The Downsides of At-Home Genetic Testing

The Downsides of At-Home Genetic Testing

Sometimes what you know can hurt you.

Did you find an at-home genetics test in your stocking this holiday season? If so, you’re not alone. Companies like 23andMe market heavily to consumers with the promise that being aware of your genetic disease risk means you can take a proactive role in your health.

To be clear, these genetic health risk reports are not diagnostic. They just tell you if you carry specific genetic markers and might be at increased risk for certain diseases or health conditions.

Before you spit into a test tube and mail your DNA sample to a lab, consider all the ramifications of taking an at-home genetics test.

Is the science trustworthy?
Perhaps not. “If you take [these at-home tests] they don’t give you consistent results,” explains Art Caplan, Ph.D., Director of Medical Ethics at NYU Langone Health. “Different labs have different interpretations of your DNA. So, the science may not be up to trustworthy levels yet.” According to the American College of Medical Genetics and Genomics, your report should provide details about the testing lab’s accreditation.

The U.S. Centers for Disease Control and Prevention (CDC) has adopted a “cautionary attitude” about at-home genetic tests. It rates them as tier 3 tests, which means there is “no evidence for clinical validity or utility of such applications in healthy individuals.”

Furthermore, the databases that companies such as 23andMe use skew heavily towards people of European decent, Caplan says. If you are in a group not well represented in the database (say, for example, Japanese American), the data may not be generalized to you.

Who’s going to help you understand and interpret the results?
Consumers may be vulnerable to being misled by results from unproven or invalid tests if they don’t have someone trained in genetics to help them interpret the report. “A lot of information regarding your health can be scary or concerning,” Caplan says, “but it doesn’t have to be. If you have a tiny risk of something and then worry about it, you may be ignoring much bigger risks you face due to poor lifestyle choices.”

Who—or what—is really to blame?
Caplan says the results of at-home genetics tests generally wind up putting the blame for problems on the individual. Say, for example, your test says you are at increased risk of asthma. The tests don’t address the fact that the coal plant down the street is putting a lot of pollution into your environment. “Test the air instead of you if you’re worried about asthma,” he says. “Everything is driven towards genetic reductionism. You’re the problem, not the environment or the dirty water or the pollutants in the air.”

Are you prepared to go down a potentially slippery slope?
Genetics is serious, Caplan says. You find out things about your background you might not want to know (for example, maybe you’re not actually related to the rest of your family in the way you thought you were).

You also might find yourself alarmed for no reason or, worse, make treatment decisions based on information that is wrong or misunderstood. According to a study published in Nature, an average person has roughly 54 mutations that are listed in genetic databases as causing disease, but for most people, they don’t. The researchers say that mistaking a prediction of risk of disease can result in medical interventions that can actually cause harm.

Another potential danger is that your data may be used without your permission or you may not be able to get disability or life insurance. Caplan says even though there are laws to protect against discrimination due to genetic conditions, the laws are weakening as the Affordable Care Act comes under attack.

Finally, a test that shows you’re not genetically at risk for any diseases doesn’t give you a free pass to smoke or eat donuts, Caplan says. “People forget it’s not just genes that put you at risk for disease. It’s your behavior.” Instead of spending money on an at-home genetics test, Caplan suggests you put it towards a health club membership. “Lifestyle is far more important to your health than genetics.”

Who should undergo genetic testing?
Genetic testing isn’t bad, according to Caplan. It may make sense if you have patterns of disease in your family, say breast cancer or certain rare genetic conditions, such as sickle cell anemia or Tay Sachs disease. In this case, go to a genetic counselor or a medical genetics department at a hospital where the lab results are more likely to be reliable and a trained genetics professional can help you make sense of the results.

“You can’t treat [genetic testing] as a fun, recreational thing if you’re serious about risk factors and disease,” Caplan says.

Medically reviewed in January 2018.

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