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April 15, 2008

Genome Scans: What do You Want to Know About Your DNA?

How much would you pay to know your genetic makeup? And once you had the information, how might it affect your behavior? Or your anxiety levels?

Anna Gosline gets to all that and more in this comprehensive story she wrote for the L.A. Times about the fall-out from her own genetic test. Gosline discovered that she has a higher-than-average lifetime risk for late-onset Alzheimer's disease -- a risk that wasn't entirely a surprise, since her maternal grandmother had Alzheimer's disease. Gosline writes:

But something about the plain and simple statement of my own genetic fact seemed shocking and terrifying.

"Genetic information has a special power," says Dr. Robert Green, professor of neurology, genetics and epidemiology at Boston University School of Medicine. "It has a feel of fate about it, a sense of inevitability, that sense that, 'Oh, you are marked.' "

But what, exactly, does that "mark" mean? And what about the accuracy? The article breaks down how the test works, what kind of information a client can expect to learn and how companies -- which charge from $1,000 to $2,500 for the results -- are trying to stay up to date with new research.

Gosline used the most expensive company, Navigenics (The New York Times covered the opening of Navigenics' temporary New York showroom under the headline, "On the Retail Front, Another Shop in SoHo for the Person Who Has Everything.") Other companies include the Google-backed start-up 23andMe and Iceland's deCODEme.

To the story's credit, Gosline includes the opinions of a number of critics of genetic testing, beginning with Dr. Muin Khoury, director of the National Office of Public Health Genomics at the Centers for Disease Control and Prevention in Atlanta, who offers this advice:

"If someone asks me, shall I take [the test]," Khoury says, "I would say 'No, you don't need it. Tell me about your family history. If you have a family history of skin cancer, stay away from the sun. If you have osteoporosis, take calcium supplements.' We know what to do."

Dr. H. Gilbert Welch, professor of medicine at Dartmouth Medical School, is also wary. A longtime critic of what he sees as an epidemic of over-diagnosis in the U.S. healthcare system, he thinks genome scans will make matters worse, especially because most doctors have little genetics training.

"I think a broad-spread application of personalized genetic testing would create havoc and would likely lead to more harm than good," he says. "It will make people anxious, and it would probably push doctors to more aggressive interventions simply because of lack of information and a feeling they had to do something."

Then there's the issue of privacy. In the U.S., there is still only limited protection from genetic discrimination. The Genetic Information Nondiscrimination Act, which would protect individuals against discrimination based on their genetic information when it comes to health insurance and employment, is stalled in the Senate, though it has passed in the House of Representatives.

OK, that part is really freaky and got me thinking about "Gattaca."

The Washington, D.C.-based Genetics and Public Policy Center is also pushing for the Food and Drug Administration to regulate consumer genetic testing.

The center's director Kathy Hudson says that though these three genome-scanning companies appear scientifically stringent and transparent in their messages, there are no laws to prevent businesses from over-selling results or providing inappropriate tests, as some have done.

In separate sidebar pieces, Gosline explains genotyping chip technology -- "small glass or silicon platforms have made quick and easy work of simultaneously analyzing hundreds of thousands of genetic variations that exist in the human genome" -- and looks at studies that tracked whether learning of a genetic risk for a particular disease led to a change in human behavior.

Readers' comments also add value to the debate. A woman who was adopted in 1953 said she has no family history to guide her, so she paid $1,000 to 23AndMe and now has "clues as to what health issues might be ahead for me in life."

Another commenter predicts that health-insurance companies will someday deny coverage based on one's genetics and concludes, "All the more reason for single-payor [sic], government provided health insurance."

So, readers, do you want to take the test?

Posted by Christine C. at 1:20PM | Permalink | Comments (3)