Friday, Jul 25, 2008
Why you should think twice before betting your life on genetic testing.
Mar 30, 1998 | It's time for every member of Congress, plus President Clinton and Al Gore, to go in for genetic testing. There's got to be a mutation or two that predisposes one to being a politician: an extra strand or two of particularly peppy nucleotides on the 21st century boosterism gene? A crippling gap in the sequence that codes for scientific understanding?
Two months ago, Vice President Gore put out a new proposal to keep employee genetic-test information from employers. It follows on the heels of last summer's wave of bills to keep the same information from health insurers.
"The fear of genetic discrimination is prompting Americans to avoid those genetic tests that are now available that could literally save their lives," Gore said in an address to the Genome Action Coalition, which promotes public support of genetic research.
Now, opposition to genetic discrimination is an easy political flag to wave, and frustrating the work of health-insurance bureaucrats is always a crowd-pleaser. But Gore's enthusiasm for genetic testing betrays the other motive in Washington for "genetic discrimination" laws: a blind belief in the manifold benefits genetic testing can confer. From this perspective, anything that prevents Americans from lining up to get genetically tested, to consume the as-yet-unproven biomedical products of our rush to decipher the human genome, is unconscionable -- deadly, even.
Which is nonsense. In fact, in these early days of genetic testing, a blood report that says you're at unknown risk of getting an incurable disease at an unknown time is as likely to take the hope and joy out of your life as to "save" it.
Admittedly, people have already lost health insurance or jobs because tests have shown they have "bad" genes. Legislation to keep the information private might not be a bad idea. But there's an even better reason to protect people from discrimination based on genetic test results: The "information" itself is often so vague as to be worthless.
If a genetic test shows you have a dangerous genetic mutation, you'll only know that you may get the disease, or maybe not -- and you won't know when. Until a test has been put through years of studies, the risk estimate it offers will typically be based on studies of small populations that took the test right after its release. And these particular groups are often more likely than most to have the disease, regardless of their genes -- that's why they're in the study in the first place.
A perfect illustration is "the" breast cancer gene, BRCA-1. The first year after it was identified in 1994, women with a certain mutation to that gene were told they had an 85 percent chance of getting cancer. But within a year, new studies lowered that to 50 percent. Last May, a study came out in the New England Journal of Medicine with a 16 percent figure. Finally, last week, two more studies came out in the Journal of the American Medical Association saying that the BRCA-1 mutation is so rare that it's "premature" for most women to take the test at all.
Many women with family histories of breast cancer leapt at BRCA-1 testing, thinking it a miraculous gaze into a crystal ball. For those confronting the terrible decision whether to remove their breasts, the test seemed to offer an extra bit of helpful evidence. But as time went on, the BRCA-1 test turned out to be less like a crystal ball and more like a weather report.
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