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Personalized gene tests are bogus? Of course they are

Opinion: Resist the lure of genetic testing advertising and its promise to tell you about your ancestry, guide your love life, or predict your future. As the GAO found, it can't.

Looks like spitomics finally got its comeuppance.

That’s what I call the growing and lucrative field of personalized genetic testing, which asks you to spit into a plastic cup and then send the sample off to a lab.

Promoters promise you can find out whether you’re at risk for cancer or heart disease, likely to have problems with certain drugs or if you’d better change your diet to avoid grisly medical problems.

Well, they all got thoroughly clobbered at a Congressional hearing this week. An undercover investigation by the Government Accountability Office found that four genetic testing companies delivered contradictory predictions based on the same person's DNA.

Investigators also found that the test results often contradicted patients' actual medical histories.

It's about time Congress, FDA took action
None of this should come as a surprise. The only surprise is that it has taken Congress and the federal Food and Drug Administration so long to go after what is nothing more than highly advertised genetic scamming.

Most of what we know about the genetic basis of disease risk rests upon a narrow sample of the population. Genetic studies are small and tend to fail to capture large categories of people, like ethnic minorities, for instance.

So saying you can sell a test which can forecast the average Japanese-American's risk for Alzheimer's disease or the average Cuban-American's risk for heart disease sits on an evidence base that is, to be very kind, completely shaky.

The companies that have entered the field do not operate with any required level of accuracy in their testing.  Nor do they have any national guidelines for how to counsel clients about the “results” of testing. 

And there is no assurance that the spit you send off to a company won't wind up being analyzed by other people working for other firms or government agencies.

Worse still, no one really has the ability to test accurately for disease risks or the likelihood of adverse events from drugs because no one knows how a single person’s lifestyle, upbringing and environment interacts with their particular genes to create risks. 

Genes alone don't tell full story
Someone who works in a coal mine, smokes three packs of cigarettes a day and lived for five decades downwind from a refinery may have the same genes as someone raised on nothing but fish and vegetables amid clean air, but they’ll each have very different risks of developing allergies, cancer or Parkinson’s disease.

Despite all this uncertain science, the companies pushing the tests insist that people have a “right” to know about their genes. 

Such talk makes for stirring language and gets people thinking that they don't want any bureaucrats, ethicists or regulators coming between them and their personalized genetic knowledge. 

Never mind that the current accuracy of the tests can’t tell you anything you would really want to know.

Because of that, the government has a proper role to play in making sure that sleazy operators and aggressive entrepreneurs are not simply separating you from your saliva for a handsome fee.

The genetic revolution has arrived, but it is not ready to take its place as a home DNA test kit next to the pregnancy test in your drug store.  Unless someone has a family history of a disease, they’re not a very good candidate for general genetic testing. 

All this will change in the future, of course. But for now, resist the lure of genetic testing advertising and its promise to tell you about your ancestry, guide your love life, or predict your future.

Your future will be far more secure if you spend your time at the gym instead of spitting into a plastic vial.

Arthur Caplan is director of the Center for Bioethics at the University of Pennsylvania.