Are Genetic Tests a Good Idea? It Depends

It sounds like something from a sci-fi novel, but this is fact, not fiction:

Americans can now order at-home genetic test kits to learn whether they have the genes for male pattern baldness or Alzheimer’s disease or bipolar mental illness.

More than two dozen companies—with names like deCODEme, Navigenics and Smart Genetics—are doing a brisk business on the Internet, selling genetic tests directly to consumers for several hundred to several thousand dollars. By spitting into a small plastic cup or swabbing the inside of the cheek—and mailing the sample back in a special pack—a person can be tested for the Huntington’s disease gene or for the “wine” gene that may help moderate drinkers lower their cholesterol levels.

The entrepreneurs argue that their tests empower consumers. But critics worry that that no one is policing the accuracy of these tests or their clinical usefulness.

“Some of these companies are responsible organizations and some are not, and it’s difficult for consumers to know which is which,” says Francis Collins, director of the Human Genome Project that has generated the flood of genetic information that’s now being hyped and sold online.

Some tests have obvious benefits. Take a family with a history of colon cancer. “You can be tested, and if you have the genetic predisposition for this cancer, we begin colonoscopy tests to monitor you in your 30s,” Collins says. “Doctors can then catch the disease early if it develops and save your life.”

The problem, though, is that “there is some real junk out there that has the potential of turning everybody off to what is a really important advancement,” the geneticist says.

Some companies are touting DNA tests to determine the best weight loss diets or the best supplements, marketing schemes that researchers say trivialize the science of genetics and the lifesaving tests it has produced.

There is also a lack of uniformity on how different companies deal with the information. Some companies market genetic tests to consumers but send the results only to their doctors, while others give the results directly to the consumer. Smart Genetics, for example, a Philadelphia-based online company, markets a $399 Alzheimer’s test and has genetic counselors telephone the test results to the consumer.

But just what does it mean to have the Alzheimer’s gene or the diabetes gene?

Collins says that simply linking a gene to a disease isn’t the whole story. “Often there is not one gene involved but many, each with a modest effect.” Moreover, even having a gene or genes associated with a disease doesn’t mean a person is predestined to have it.

“There are very few genetic tests that determine [if] the person will get a disease, and they are all for rare, single-gene disorders like Huntington’s disease,” Collins explains. “What most tests today show is your risk for a disease. If you have the Alzheimer’s APOE 4 gene, your risk goes up by a factor of three. That does not mean you will get Alzheimer’s. And if you don’t have the APOE 4 gene, that doesn’t mean you won’t. The result isn’t a definite yes or no.

“Once you identify genes linked to a disease,” he adds, “you can almost immediately predict who is at greater risk for a disease. But that is not so interesting if there is nothing you can do about it.”

But Julian Awad, CEO and cofounder of Smart Genetics, says that while there is no treatment or cure for Alzheimer’s, the results of genetic tests are “tremendously useful. People can think about legal and financial plans, long-term care. They can get more education and get involved with research and clinical trials.”

Currently, there are tests for about 1,500 diseases and conditions, according to the Genetics and Public Policy Center at Johns Hopkins University in Baltimore. A center study published by the journal Science in April found no mechanisms that are in place to ensure that genetic tests are supported by adequate evidence before they are marketed, or that marketing claims are truthful.

Collins says that an NIH advisory committee on genetic testing has recommended beefing up government oversight and establishing a public website for consumers who want to find out whether a test is valid or whether knowing its results would be useful.

“I firmly believe,” Collin says, “that with more research to guide us, genetic testing offers us a great opportunity to practice preventive medicine in a way that focuses more specifically on what each of us ought to do for our health. It is a great new model, but right now we don’t quite know how to implement it.”