Too Much Information
Tuesday, June 13, 2006
Imagine being able to order a genetic test over the Internet -- to see if you have inherited a predisposition to cancer or whether there might be a genetic component to your infertility -- without having to get approval from your doctor, consult a genetic counselor or risk the fallout that might result from filing an insurance claim.
Now imagine sitting alone at your home computer and receiving devastating news: test results that will forever change your life -- and your family's -- in ways you never anticipated.
Those are the promises and perils of the nascent, growing and largely unregulated phenomenon of direct-to-consumer (DTC) genetic tests. For the price of a mail order test kit containing swabs to scrape cells inside the cheek, nearly a dozen companies now offer curious consumers the chance, without ever seeing a doctor, to learn whether they carry genes for cancer, blood disorders or other diseases. Some companies are marketing personalized diet or skin care recommendations based on DNA analysis using tests that are not widely accepted in the scientific community.
Spawned by a burgeoning interest in self-care fueled by the Web and the completion in 2003 of the federal Human Genome Project, home testing enables users to "be proactive in managing their care" from the privacy of their homes, according to San Francisco-based DNA Direct, a leading purveyor of DTC genetic tests. An article last month in Good Housekeeping pronounced the process "as simple as ordering takeout."
That kind of characterization alarms experts in genetics, a technical and highly complex specialty. Testing, they say, should remain the province of specialists who can advise, educate and counsel patients -- not of companies that may resort to hype and fear-mongering as marketing tactics or whose employees may not understand the nuances of risk and probability that are central to genetics.
Two examples of what troubles experts: A woman tested for hereditary breast cancer may mistakenly think a negative result on a home test means she can forgo regular mammograms. In fact, breast cancer genes account for only a fraction of cases. Similarly, someone who receives a positive finding on a DNA-based colon cancer screening test may have cancerous polyps that can be removed, colon cancer that has spread or neither because the test is a false positive.
In 2004 the Bethesda-based American College of Medical Genetics advised the public to avoid home tests, which it called "potentially harmful," citing the possibility of "inappropriate test utilization, misinterpretation and other adverse consequences." Genetic testing, medical geneticists say, should be ordered and interpreted only by an "appropriately qualified health care professional" who counsels families before and after testing about their risks for the presence of or susceptibility to inherited diseases, such as cystic fibrosis or various cancers, and advises them about follow-up care.
Counselors say they are worried about the impact of results conveyed online that can cause unnecessary anxiety -- or inappropriate reassurance. A positive finding can trigger extreme distress, even in patients who have undergone pretest counseling. And many patients erroneously think an elevated risk of genetic disease means they are sure to develop it.
"This can be really, really shocking, especially if you really don't know what you're getting into," said Scott M. Weissman, co-chair of the Familial Cancer Risk Counseling Group for the 2,000-member National Society of Genetic Counselors (NSGC). "Testing may do more harm than good."
Kelly E. Ormond, director of the genetics counseling program at Northwestern University and past president of NSGC, agrees. "It's not like being pregnant. There are a lot of gray areas, and correctly interpreting what those mean is really important." So, she said, is informing patients about the limitations and uncertainties of a test, such as its rate of false positives and false negatives -- advice that can be overlooked in online encounters.
Another concern is that genetic testing exists in a regulatory vacuum, notes lawyer Gail H. Javitt, policy director of the Genetics and Public Policy Center at the Berman Bioethics Institute of Johns Hopkins University.
The Food and Drug Administration regulates test kits that are sold to labs to detect about a dozen genetic diseases. But the vast majority of DNA tests are "home brews," in industry parlance: tests assembled, sold and analyzed in-house by various labs.