DNA Tests Return Varying Results On Disease Risks

Kira Peikoff, 28, had her DNA tested by three direct-to-consumer companies; the results didn’t agree.

Graduate student Kira Peikoff sent her DNA specimen to three laboratories. She received different results:

I Had My DNA Picture Taken, With Varying Results, New York Times, 30 December 2013

“23andMe said my most elevated risks — about double the average — were for psoriasis and rheumatoid arthritis, with my lifetime odds of getting the diseases at 20.2 percent and 8.2 percent. But according to Genetic Testing Laboratories, my lowest risks were for — you guessed it — psoriasis (2 percent) and rheumatoid arthritis (2.6 percent).”

These tests don’t inform with actionable risks.  They don’t take into account lifestyle, environment, or any other variable that affects disease risk. Only genes, and then, only parts of genes. As Peikoff describes, they only examine a few segments of DNA, they don’t analyze your whole genome.

Here’s Dr. Robert Klitzman, a bioethicist and professor of clinical psychiatry at Columbia.

“Imagine if you took a book and you only looked at the first letter of every other page, … You’re missing 99.9 percent of the letters that make the genome. The information is going to be limited.”

Also, labs look at different DNA segments, compare those segments to different databases, and interpret them differently … even when they’re investigating a risk for the same disease.

If these companies return inaccurate risks, it can lead to harm. In…

Understanding Population and Individual Risk Assessment: The Case of Polychlorinated Biphenyls, Cancer Epidemiology, Biomarkers and Prevention

… Shields used the case of PCB exposure as an example of how to relate population data with individual risk, cancer risk in this case. He said that misinterpretations…

“… can lead to false conclusions about what caused a cancer in a specific patient, undue anxiety about future cancer risk, inappropriate cancer screening, and attendant increased morbidity due to increased uses of the medical system and complication rates from medical procedures. The communication of research findings by scientists must be presented with caution, resisting the temptation to extrapolate, inappropriately, research data to the general population.”

These tests are not standardized, they’re not validated, and they’re not actionable.  The FDA sent a warning letter to one of the companies, 23andMe, telling them to stop marketing the test for health-related conditions until they provide evidence of the test’s validity.

I don’t know how these tests are being sold as providing accurate and useful health information.  Maybe they aren’t.  Maybe they are just an expensive party game.  Dr. Caplan, director of medical ethics at New York University said:

The tests “may be interesting as a kind of entertainment, but do not take them seriously yet in driving your health care or your lifestyle. … He added: “If you want to spend money wisely to protect your health and you have a few hundred dollars, buy a scale, stand on it, and act accordingly.”

2 thoughts on “DNA Tests Return Varying Results On Disease Risks

  1. Pingback: The Risks Of Direct-To-Consumer Gene Tests | Fanatic Cook

  2. Ebon Talifarro

    Hey, I’m Ebon Talifarro, my class (8th grade) wants to interview you, would you have time to answer a few questions?


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