Putting the brakes on home genetic testing: Four questions with geneticist Scott Diehl

December 4, 2013 by Rob Forman, Rutgers University

The Food and Drug Administration recently ordered an end to sales of the home genetic testing kit 23andMe. FDA medical experts said the kit's manufacturers had failed to prove their claim that the $99 test can help customers make informed decisions about their health, despite being asked for that proof for more than five years. 23andMe says that in 2013, more than 200,000 people have purchased its product.

According to the company's website, by analyzing DNA from a sample of a customer's saliva, "23andMe helps you know more about your health so you can take an active role in managing it." But the FDA says that customers may be risking their lives if they rely on test results to make important health-related decisions.

Scott Diehl is director of the Center for Pharmacogenomics and Complex Disease Research at the Rutgers School of Dental Medicine, and a longtime critic of tests such as 23andMe, which derives its name from the fact that human cells contain 23 pairs of chromosomes. Diehl says ordering the test off the market was the right decision.

What is wrong with letting consumers buy a product that tells them more about their DNA than they knew before?

The picture the test gives people is so incomplete as to make it useless. For years, 23AndMe has been telling unsophisticated consumers that their risk of highly complex disorders such as diabetes, rheumatoid arthritis, Celiac disease, heart disease, stroke and schizophrenia is higher or lower based on just one or two inherited genetic variations. Most geneticists are convinced that risk of these diseases is determined by thousands of variants. Relying on these home testing kits is like predicting whether your car will break down during a long journey after you've only checked whether a couple of lug nuts on one of the wheels are sufficiently tight.

But even if the information is limited, is there any harm in it?

These incomplete tests for complex diseases may mislead people into thinking their risk is higher or lower than it really is, and they might fail to take important steps such as weight loss, improvements in diet or increased exercise because of a false report of low risk for a condition such as diabetes or .

What about tests for certain life-threatening illnesses?

Tests that predict a person's risk for deadly conditions like breast cancer or serious side effects of medications really have no place in the direct-to-consumer market. These tests require guidance and interpretation by doctors and trained genetic counselors because decisions can have major health consequences as well as psychological effects on the patient and family members. Few people without medical training have sufficient knowledge to understand what such tests really mean. The tests' limitations could scare some people unnecessarily while lulling others into a false complacency so that they fail to follow up with their doctors and get the far more rigorous and comprehensive testing that can be performed by a medical genetics laboratory.

Could further advances in testing technology, knowledge of genetics or added safeguards make home genetic testing acceptable to you in the future?

Although the cost of DNA assays has been coming down very rapidly, the challenge of interpreting the deluge of data has gotten far greater. Testing for diseases that have serious needs to be very carefully controlled. Today there are dozens of companies aggressively marketing tests for health conditions for which there is little or no clinical validation. It is in the public interest for the FDA to provide oversight of this growing industry so that consumers aren't paying for worthless information and so the have well-documented clinical validity just as the FDA requires for drugs and medical devices.

Explore further: US tells 23andMe to halt sales of genetic test

Related Stories

US tells 23andMe to halt sales of genetic test

November 25, 2013
The U.S. Food and Drug Administration is ordering genetic test maker 23andMe to halt sales of its personalized DNA test kits, saying the company has failed to show that the technology is backed by science.

It is game over for 23andMe, and rightly so

November 27, 2013
The market for personal genome services is facing a reality check. While the most prominent and innovative company 23andMe has flourished so far, in the past few years many of its competitors have gone out of business. Now, ...

23andMe faces class action lawsuit in California

December 3, 2013
Genetic testing company 23andMe is facing a class action lawsuit alleging that the Silicon Valley startup misled customers about its test kit.

Study finds that Americans want doctors' guidance on genetic test results

November 7, 2013
In an era of commercialized medicine, direct-to-consumer (DTC) genetic testing has been on a steady rise. Consumers can purchase a DNA sample kit, also known as a "spit kit," mail it to a testing company, and wait for an ...

Direct-to-consumer genetic testing kits vary in predictions of disease risk

July 17, 2013
(Medical Xpress)—An in-depth analysis and comparison study conducted by investigators at Emory's Rollins School of Public Health demonstrated variations in predicted disease risks by companies that offer direct-to-consumer ...

Comparing family history and genetic tests for predicting complex disease risk

October 15, 2012
In a new theoretical study, 23andMe, the personal genetics company, developed a mathematical model which shows that family history and genetic tests offer different strengths. The study results suggest that both family history ...

Recommended for you

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

Two new breast cancer genes emerge from Lynch syndrome gene study

January 18, 2018
Researchers at Columbia University Irving Medical Center and NewYork-Presbyterian have identified two new breast cancer genes. Having one of the genes—MSH6 and PMS2—approximately doubles a woman's risk of developing breast ...

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

Can mice really mirror humans when it comes to cancer?

January 18, 2018
A new Michigan State University study is helping to answer a pressing question among scientists of just how close mice are to people when it comes to researching cancer.

Epigenetics study helps focus search for autism risk factors

January 16, 2018
Scientists have long tried to pin down the causes of autism spectrum disorder. Recent studies have expanded the search for genetic links from identifying genes toward epigenetics, the study of factors that control gene expression ...

Group recreates DNA of man who died in 1827 despite having no body to work with

January 16, 2018
An international team of researchers led by a group with deCODE Genetics, a biopharmaceutical company in Iceland, has partly recreated the DNA of a man who died in 1827, despite having no body to take tissue samples from. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.