DNA by Mail: Personal Genomic Testing

You can order your own personal genomics tests online now — but should you?

DNA illustration

You can order a lot of things online these days: electronics, clothes, music, even groceries. But did you know that you also can order your very own DNA test?

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Personal genomic testing is now being marketed to individual consumers and businesses. The basic idea is that you get a saliva sample kit in the mail, then work through a company or a physician’s office to have it tested and interpreted. It’s an interesting concept — but is it worth doing?

The two most recognizable companies in this field are 23andMe and Navigenics, which work a bit differently. 23andMe allows and encourages individuals to order kits and obtain results themselves, aligning with the company’s primary goal of engaging and empowering consumers in their health. Navigenics offers genomic testing profiles through physician offices, requiring that physicians and patients obtain some degree of formal education through the process. Navigenics claims to include only tests that are clinically actionable — meaning tests that you can act on to improve your health.

In contrast, 23andMe includes tests for traits or conditions that may be more recreational — traits such as the ability to smell asparagus in one’s urine, or who is likely to have straight vs. curly hair. 23andMe also includes genealogy and encourages participation in social networking groups.

The trouble with interpretation

The next step is where things get tricky. Interpreting personal genomic tests requires a fundamental understanding of genetic principles. Once a sample is received in the lab, the sample is tested for a range of SNPs (single nucleotide polymorphisms) — DNA sequence variations — that have been associated with disease. Some SNPs track closely with disease risk, but others are not so clear.  Some associations are stronger depending on your ethnic background, too.

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Interpretation should be undertaken with caution, particularly for the untrained eye. Our general principle is that patients should follow up on any positive risk or association with additional tests or referral to a medical geneticist, someone who truly understands this complicated science. On the flipside, negative risk or association may provide false reassurance. You should not interpret it as lack of risk. Remember that most conditions are based on many factors; genetics is only one of them.

Because of these complexities, most personal genomic testing companies now offer genetic counseling services. In fact, Navigenics requires interaction with their genetic counselors as part of the testing process.

Why it is worthwhile

Despite the need for caution, personal genomic testing provides an opportunity for us — all of us, both providers and patients — to learn about genomics and its role in predicting disease risk and adverse drug responses. It can also provide an opportunity to investigate your heritage and network with others who share similar genealogy and disease risk.

Perhaps most important, personal genomic testing can offer a way for you to engage in medical philanthropy — the donation of DNA towards large-scale research studies. One such study is being done by 23andMe in collaboration with Cleveland Clinic. This study is currently recruiting patients with Parkinson’s disease with the hope of finding novel genetic variants associated with the disease.

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By taking part, you and your DNA may contribute to research discoveries and medical breakthroughs.

Have you tried personal genomics testing? Tell us about your experience in the comments section below.

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Kathryn Teng, MD

Kathryn Teng, MD, is Director of the Center for Personalized Healthcare and leads Cleveland Clinic’s efforts to integrate personalized healthcare into standard practice.
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