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Study reveals flaws in gene testing; results often conflict

 
Published May 28, 2015

The first report from a big public-private project to improve genetic testing reveals it is not as rock solid as many people believe, with flaws that result in some people wrongly advised to worry about a disease risk and others wrongly told they can relax.

Researchers say the study shows the need for consumers to be careful about choosing where to have a gene test done and acting on the results, such as having or forgoing a preventive surgery.

"We have very clear documentation that there are differences in what patients are getting" in terms of how tests on the same gene variations are interpreted, said the study leader, Heidi Rehm, genetics lab chief at Brigham and Women's Hospital in Boston.

When deciding to get tested, either through a doctor's office or by sending in a swab to a private company, "patients need to choose labs that are sharing their data" with the broader research community so scientists can compare and learn from the results and make testing more accurate for everyone, she said.

Dozens of companies now offer gene tests to gauge a person's risk of developing various disorders. One of the newest tests on the market costs $250 and checks about 20 genes that can affect breast cancer risk.

But not all gene mutations, or variants, are equal. Some raise risk a lot, others just a little, and some not at all. Most are of unknown significance — a quandary for doctors and patients alike. And most variants are uncommon, making it even tougher to figure out which ones matter and how much.

To solve these mysteries and give patients better information, the U.S. government several years ago helped form and fund ClinVar, a database for researchers around the world to pool gene findings, coded to keep patients' identities confidential. More than 300 labs contribute to it, including universities such as Harvard and Emory and some private companies such as Ambry Genetics and GeneDX.

On Wednesday, the group made its first report at a conference in Washington. The study also was published online by the New England Journal of Medicine.