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Gene guilt by association

More marketing than science

A version of this commentary appeared in Straight Goods

Peoples’ curiosity about themselves seems to know no limits and this is proving to be profitable for companies hoping to cash in on that curiosity.  We see it again and again — ads for home DNA test kits appealing to consumers’ interest in their ancestral past and lured by the promise of getting a personalized genetic roadmap to help them predict their likelihood of future health conditions.

These genetic screening services are getting very simple. Go online, plunk down $100 for a test kit. When it arrives, send in a sample of your saliva, and sit back and wait until the report arrives, telling you your chances of getting Alzheimer’s or glaucoma when you get old.

For example, last summer the personal genetics company 23andMe, which offers their services in Canada, announced that its DNA database contained the genetic information of over 100,000 people — likely the world’s largest collection of individual genetic information. This information will be used to research the connections between a person’s DNA and his or her risks of developing certain diseases.

With the exponential growth in the sophistication of DNA analyses and the promise of unlocking genetic secrets, many people are using services like 23andMe as a kind of genetic horoscope, trying to get some insights into future health risks.  However, a decade’s worth of analyses of genetic screening services have shown that they almost always promise more than they can deliver and have serious limitations.

Gene guilt by association

For one thing, the genetic variations (also known as SNPs or single nucleotide polymorphisms) found in your DNA sample may be “associated” with diseases, but that doesn’t necessary imply “causation.”

In other words, just because a genetic test says your genes carry a “higher than normal” chance of developing Alzheimer’s or Type 2 diabetes, that doesn’t necessarily mean you will acquire it.

Both nature and nurture are involved in determining whether or not any of us will develop a disease in the future, and society’s understanding of the interplay between those two factors is still in its infancy.

With the exception of a few tests with scientific backing — like genetic screening for BRCA, the “breast cancer gene” — for most genetic screening tests, the science is still miles behind the marketing.

Marketing your worst fears

Getting definitive answers from a personal genetic decoding service is rare — what isn’t rare is the misleading advertising often associated with these tests.

Recently, the U.S. Government Accountability Office conducted a review of online businesses offering genetic testing and lifestyle counseling services.  They sent the same samples to a number of companies and found predictions all over the map, examples of egregious and deceptive marketing and claims that a consumer’s DNA could be used to create personalized supplements to whatever diseases they were facing.

Their conclusion?  “These tests do not provide meaningful information to consumers.”

Studying the facts before taking the test

Despite the promise of a genetic crystal ball, the truth is, we don’t fully understand the relationship between our genes and disease.  Science doesn’t really know yet what it means for you when something shows up in your DNA.

Some would argue that completing a personalized genetic test allows you glimpses into the depths of your own genetic makeup and an opportunity to contribute your DNA to a worthy cause.

Perhaps, one day, DNA databases might be hundreds of times more powerful, and there may be genetic breakthroughs that may help many of us live better lives.  That’s the hope.  But, we’re far from there today.

Alan Cassels is an expert advisor with EvidenceNetwork.ca. He is also a drug policy researcher at the University of Victoria and the author of Selling Sickness. His next book, Seeking Sickness, is on the medical screening industry.

January 2012

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