Say you were concerned about the structural integrity of your house, about the possibility that it may not be standing in 20 years. You’d want to see your home’s blueprints, you’d want a structural engineer to interpret those blueprints, and you’d want that information quickly and conveniently.
Scientists have known that DNA is the blueprint for our bodies for more than a half-century. But only recently have they begun to really untangle what key elements of those blueprints can mean for health. Genetic tests today might reveal whether your DNA places you at risk for, well, all sorts of things.
If you believe the press releases and promises on websites, you may not even need your doctor or a genetic specialist to help you decode the results. Just a kit and a mailing address will do. On the cheery, pastel-colored website for 23andMe, it couldn’t be simpler: “1) Get Your Kit, 2) Provide your Saliva, 3) Learn About Yourself, 4) Get Monthly DNA discoveries.” For $99, you can spit into a tube, mail it off, and within eight weeks discover hints about your past — and future. 23andMe promises information about your genetic ancestry, your likelihood of going bald, and your risk factors for 97 different diseases, from Alzheimer’s to bipolar disorder to male infertility.
The DNA strands from the cheek cells in your spit, the website explains, are diced, and placed on a modified glass slide that detects specific variations of DNA snippets. From there, 23andMe correlates information from your DNA sample with research on what those snippets of DNA mean, and then draws all sorts of conclusions.
The $99 kit requires a year-long, $9-a-month subscription that includes updates with new research discoveries or technological upgrades. A bit like a Newsweek subscription, in other words, though one that purports to tell you your resistance to AIDS.
In October of 2008, Time magazine named 23andMe’s service its Invention of the Year. Time’s profile of the test and two founders recognized there were controversies surrounding the technology, but mostly the report glows. To the left, an infographic of an attractive young woman is labeled with nearly a hundred things that, purportedly, 23andMe could tell about her from her DNA: She has increased odds of getting multiple sclerosis, average odds of heroin addiction, a slim chance of being a track star, a 6 percent chance of getting lung cancer.
23andMe doesn’t officially make the claim it will save your life. Instead, it has Kirk C. — a customer — who offers his testimony: “Because I had given my doctor information from 23andme, he got to a diagnosis much faster. 23andMe saved my life.”
But not everyone’s sold. Last year, Walgreen’s announced they would sell similar kits, from the San Francisco-based Pathway Genomics, across over 6,000 stores. But after the FDA sent a letter to Walgreen’s cautioning them, the drugstore chain reversed its decision. According to the FDA, “None of the genetic tests now offered directly to consumers has undergone premarket review by FDA to ensure that the test results being provided to patients are accurate, reliable and clinically meaningful.”
Robin Bennett is a genetic counselor at the University of Washington School of Medicine. “[Genetic tests] are based on assumptions on how common a disease is. Most have been [based] on Caucasians or northern Europeans,” Bennett says. Genetic testing companies don’t have the same swath of information — about weight, lifestyle, race and family history — that your doctor has.
“I don’t think the companies are trying to do a bad job,” Bennett says. “There’s a lot that goes into the interpretation of the tests. It’s just that they may not have all of the facts.”
These sorts of tests can make two types of errors, Bennett says, both with possible consequences: When they overstate your chance of getting a disease, it can cause unneeded stress, and may lead to unneeded tests and dangerous, expensive and unnecessary surgeries. And if it understates your actual chance of getting a disease, you could ignore other signals that should worry you.
“You could ignore the signals of rectal bleeding,” Bennett says. A consumer might think, “‘I had that test, and I don’t have a risk of colon cancer’” and ignore actual physical symptoms.
Read closely on your printout from 23andMe and you’ll see that some data points have four stars for confidence (like psoriasis or multiple sclerosis). That means there have been large-scale, thorough, peer-reviewed studies on the markers for those diseases. But for the majority of conditions, the data isn’t that strong. Tourette syndrome, or male infertility, for example, only have one star, meaning they were based on fewer than 100 people studied.
Until technology improves, there are better indications, Bennett says, for your risk of a disease, such as whether it runs in your family.
“I don’t think I would call [direct-to-consumer genetic tests] inaccurate. I feel these tests are … not quite ready for the utility that may be touted,” Bennett says. “Their money might be used for something better. Like a massage to relax instead of a blood test.”
