Critics also say privacy laws related to genetics aren't strong enough, putting those who take the tests at risk for discrimination. And they say there isn't enough regulation governing what companies can and cannot purport to know, leaving consumers vulnerable to being scammed. The Food and Drug Administration does not currently have authority over the claims companies can make about the tests, though a bill is pending in Congress to give the agency that power in direct-to-consumer advertisements.
The critics emphasize that there's no clear research that shows the tests are any better at predicting future health problems than a simple survey of family history combined with ordinary lab workups.
Genelex Corp. Chairman Howard Coleman says genetic testing could "radically transform health care," but some scientists are critical of personal DNA health reports.
(Ariana Eunjung Cha -- The Washington Post)
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"That these type of genetic tests have a high predictive value is a myth," said Sujatha Byravan, executive director for the Council for Responsible Genetics, a think tank in Cambridge, Mass. Barbara Brenner, executive director of San Francisco-based advocacy group Breast Cancer Action, said the marketing of some of the genetic assessments is unethical: "The fear of disease and amount of misinformation about what we can do about it is leading a lot of people to needlessly take the tests."
When Genelex first rolled out its $395 nutritional genetic test in 2002, it was mostly the wealthy who signed up. Now, says Coleman, the demographics are across the board: including those with chronic disease, athletes, and ordinary people hoping to optimize their health.
For those who sign up, it's about playing the odds -- like wearing a seat belt, putting on sun block or forgoing a swim during a lightning storm. "We are not giving people certainty. We are just giving them a little more information to fine-tune the choices they make. It's a risk analysis," said Carolyn Katzin, a nutritionist for the University of California at Los Angeles executive physical program who also consults for Genelex. She said about 10 percent, or 50, of her private practice patients have taken the Genelex DNA test.
Eveline Ginzburg, 62, a relationship counselor from Los Angeles, took Genelex's nutritional test in the fall of last year after she found out she had high cholesterol levels in her blood. "It was surprising to me because I'm very active and not overweight and I thought I had a pretty healthy diet. My doctor said it must be familial," she said.
From the test, she learned that one parent had passed on a gene to her that Genelex said appeared to make her vulnerable to heart disease. Learning that her problem might be genetic pushed her to accept the need for medication, something she previously had resisted. Thanks to the pills and a slightly modified diet, her cholesterol is now down to normal levels.
"I wanted to be proactive instead of reactive," she said.
The human body's blueprint is made up of between 20,000 and 25,000 genes. Every person has two copies of each gene, one inherited from each parent. Genelex's nutrition test looks at 19 of these pairs, most of which are involved in how the body handles substances such as vitamins.
Genelex and other firms that market nutritional tests say they are based on previous scientific research that has been peer-reviewed. Patrick Hanaway, chief medical officer of the Great Smokies Diagnostic Laboratory in Asheville, N.C., which offers tests similar to those of Genelex, said its assessment of the genes that deal with the removal of toxins, for example, is based on a number of studies, including one published in Cancer Research in 1998. It found that smokers overall had a risk three times greater than nonsmokers of developing bladder cancer. But if you broke the smoking group down further based on a gene that was related to how the body handles smoke, those with two normal copies had a risk that was only two times greater. Those with one good gene and one bad one had a risk four times greater. And those with two bad genes had a risk seven times greater.
"Just as we all have different hair color and eye color, we all have different genes that determine how our bodies work. They may have only small little differences, but that means what's good for me and what's good for you may not be the same," Hanaway said.
This might explain, some researchers say, why some smokers suffer from cancer and other complications at a young age and die while others, like comedian George Burns, who was famous for his daily cigars, live to the age of 100.
Jose Ordovas, director of the Nutrition and Genomics Laboratory at Tufts University, said companies are exaggerating the scientific basis of such claims. "In terms of really solid proven evidence, there is very little for any nutritional genetic test that is being commercialized to date," he said.
Among the most passionately debated aspects about genetic tests is whether they should be sold to consumers without the buyers having to go through their doctor or a genetic counselor. Great Smokies requires that customers go through a professional, saying that the results can be confusing or scary if not properly understood. But Genelex and plenty of others allow consumers to request the tests on their own, because they say it empowers patients and ensures their privacy.
But Columbia University medical professor Nancy Wexler, who discovered the Huntington's disease gene, says direct-to-consumer sales are "a catastrophe." As a result of tests that predict a negative outcome, people might "cut off their best friends, jump off the Golden Gate Bridge." They might also decide not to have children because they are worried they will pass on similar health problems.
Wexler said the psychological impact of genetic testing can be as dramatic as the physical.
"Even if the test can save your life, it's often not good news," she said. "It knocks people for a loop."
