Buyer Beware: Over the Counter DNA Tests Can Cause More Harm Than Good

Coming-of-age movies set in the 1950s and '60s sometimes show a teenage boy in a drugstore asking for a Coke, comic book, condom and candy, hoping the stern pharmacist won't notice. And in the 1980s women still needed a doctor for a pregnancy test or anti-yeast preparation like Monistat.

But today, even as direct-to-consumer advertising (DTC) exhorts people to tell their doctor what they need (on the basis of the medical school they attended called TV), other products are starting to bypass the doc altogether.

Claritin, one of the first drugs sold DTC, graduated to over-the-counter sales a few years ago along with its allergy drug cousins Zyrtec and Benadryl which also once required a prescription. Home tests for blood sugar, cholesterol, urinary tract infections, HIV and illicit drugs like cocaine and marijuana are now commonplace.  And then there's the at-home DNA tests Walgreen's almost marketed last week. 

San Diego-based Pathway Genomics Corporation planned to place the Insight Saliva Collection Kits in 6,000 Walgreen stores until the FDA said, "You're selling WHAT?" and it put its plans on hold. The $20-$30 genetic testing kits --  essentially containers for saliva that customers mail in for analysis at Pathway's labs -- would predict someone's risk of diseases, chance of transmitting health problems to offspring and reaction to prescription drugs. The company, which was incorporated in 2008, also markets ancestral DNA tests.

Are you at risk for heart attack, venous thromboembolism, peripheral arterial disease, high blood pressure, abdominal aortic aneurism, leukemia, colon, lung, prostate and breast cancer? Diabetes, obesity, polycystic kidney disease, multiple sclerosis, macular degeneration and exfoliation glaucoma?  Do you risk psoriasis, restless leg syndrome, rheumatoid arthritis, asthma, atrial fibrillation, cystic fibrosis and celiac, Crohn's, Huntington's, Parkinson's and Alzheimer's disease? For additional fees, Pathway will tell you if your genes predispose you to these conditions. (And you thought you were healthy.)

Of course DNA self-tests were already available online from companies like 23andMe and Navigenics before the Walgreen announcement. And DNA paternity tests have been sold at major drugstores by Sorenson Genomics and Identigene for over two years. But Insight, if sold, widens the window of DNA products sold with no pretense of a need for clinical geneticists, genetic counselors, scientists or other health professionals to interpret results for consumers.

In response to the do-it-yourself breakthrough, the National Cancer Institute, Federal Trade Commission and new director of the National Institutes of Health, Dr. Francis Collins, have all questioned the predictive value of the tests. Collins, who presided over the Human Genome Project from 1993 until its completion in 2003, sent his own DNA to three major testing companies with a disappointing outcome, the San Diego Union-Tribune reported.

"They were not consistent in how they interpreted the results," Collins said. "I think all the companies probably overrepresented the degree to which we already can predict people's future risk of illness and underrepresented how much of heritability has yet to be discovered."

Others like Robert Superko, a metabolic and genetic specialist at Atlanta-based St. Joseph's Hospital don't doubt the predictive value of knowing if you have a "heart attack gene" but caution against do-it-yourself testing without the expertise of doctors or genetic counselors to interpret test results.

Many fear that unlike a home urinary tract infection test, genetic home tests open the public up to biotech/industrial adventurism. "This kind of direct-to-consumer advertising is troubling because it begins a concerted campaign to desensitize the public to the very real dangers of genetic engineering," says Robert Davidson, who practices internal medicine in Gladewater, Texas. "The recent contaminants found in rotavirus vaccines highlight the risk of horizontal transfer of genetic material between species and there are literally hundreds of such 'innovative' new inoculations in the pipeline."

And there are other questions. Will a lab sell your DNA for testing or research? Will employers and insurance companies learn your results and discriminate? And what is the role of pharma?

One of the actions of Pathway's at-home gene test is confirming on the basis of DNA how well users will respond to prescriptions like the anti-clotting drug Plavix, breast cancer drug Tamoxifen, blood thinner Coumadin and statins. How soon before "statin responders" get scare emails and marketing campaigns targeting them for AstraZeneca's Crestor or Pfizer's Lipitor given that pharma/DNA testing firm partnerships are the next big thing?

In fact, when you think of the profit potential your DNA represents to bio-enterprising companies, the real danger of at-home DNA kits is probably not the lack of a genetic counselor, but the lack of a legal one.

Martha Rosenberg frequently writes about the impact of the pharmaceutical, food and gun industries on public health. Her work has appeared in the Boston Globe, San Francisco Chronicle, Chicago Tribune and other outlets.