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Genetic testing requires more than a saliva sample kit.

Genetics

Personal genomics sounds like the stuff of science fiction. But unraveling an individual's DNA can provide clues to health indicators with a genetic basis, such as an elevated risk of heart disease or a drug sensitivity. This information may in turn compel someone to be proactive about their health, and make lifestyle changes such as exercising more or avoiding certain prescriptions.

As our understanding of genetics progresses, experts predict that more health care will be tailored to the individual. With the boom in biotechnology and the falling costs of genome analysis, a number of companies offer testing directly to consumers. On the surface, it sounds like a great idea: order a test kit online, mail off a saliva sample and in a few weeks, learn everything about yourself from telltale mutations to ancestry analysis. You have unfettered access to your own DNA.

"Not so fast," says Karen Litwack, director of the Chicago Center for Jewish Genetic Disorders.

A number of scientific, ethical and legal issues complicate matters. First and foremost, many testing kits and promotional materials from direct-to-consumer (DTC) companies omit a vital factor: genetic counseling.

"Without consulting a genetic counselor before and after testing, even the most sophisticated consumer may not understand what they are being tested for, and have no real way of understanding or interpreting results on their own," said Litwack. Genetic counselor Michelle Gilats, who recently tested one service (23andMe), agreed. "I do this for a living and yet some of the results still freaked me out," she said.

The science of analyzing a genome is still very new, which means that genetic testing results are not clear-cut. Not all the relationships between genes and mutations are understood or even identified. One disorder can have hundreds of mutations—cystic fibrosis, for instance, has more than 1,500 known to date—and depending on a person's ethnicity, certain types of tests may not be looking for the right mutations at all. Ethnic background and family history are important contexts for testing and interpreting results. Without genetic counseling, many DTC tests place the burden of understanding this context on the consumer.

"One of the things they can test for is lifetime risk for developing Parkinson's disease, based on one genetic marker," said Gilats. "You may read that you have a greatly increased risk for Parkinson's, but you also need to be aware that this disorder has less than one percent basis in genetics. The problem is, it's the initial risk number that's going to stick in people's minds."

Knowledge without proper context or explanation can cause great anxiety or lead consumers to take actionable steps which may be unnecessary or even harmful.

At present, DTC tests are marketed not as diagnostic but as informational products, which would exempt them from government regulation. Recent uproars, including an announcement (and later retraction) by Walgreens that it would sell testing kits for under $30, have prompted Congress and the FDA to scrutinize the industry. Federal regulators have now told five companies that their testing kits are unapproved medical devices, and must be approved by the FDA. Many independent investigations have demonstrated that tests claiming to analyze the same characteristic, particularly factors such as disease risk, give varying results, further underscoring the need for standardization and establishment of best practices.

While DTC genetic testing is a work in progress, companies are taking some positive steps, including offering genetic counseling services or requiring that customers order tests through a physician's office. Litwack is pleased to see companies heeding calls for change.

"It looks like we know a lot more than we do," she said, "and we need to be careful about how this information is gathered and dispersed." Letting DTC companies drive the movement toward personal genomics may not be the best route for consumers, she added. "Health professionals and community members need to participate in this process, to ensure that these tests are really informing people in an educated, supportive way."

Esther Bergdahl is the program associate at the Chicago Center for Jewish Genetic Disorders. Visit www.jewishgenetics.org for continuing updates on this issue, as well as a forthcoming consumer's guide to DTC genetic testing.

Posted: 7/1/2010 12:34:42 PM
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