UW experts warn of limitations in home genetic testing kits
Nov 27, 2013, 3:47 PM | Updated: Dec 2, 2013, 6:16 am
Advances in science and medicine have brought the laboratory into our homes to learn if we’re pregnant, HIV positive, or even find out which neighbor dog is pooping on our lawn.
Genetic screening is the latest home testing craze – but it comes with a new government warning.
The Google spin-off company 23andMe is marketing a home genetic testing kit for $99, with a lofty goal of transforming health care.
“I totally believe in this world, it’s going to be possible to be healthy at 100,” said Anne Wojcicki, 23andME cofounder.
Hers is the latest company to offer what some call recreational genetic testing. The 23andMe test offers customers knowledge about their heritage and promises early warning about a genetic risk for disease, including cancer. Recently, on CBS This Morning, Wojcicki revealed that her personal genetic test results showed an increased risk for breast cancer, prompting her to stop drinking, for one.
“It was really empowering for me to actually get information where I felt like I could make lifestyle changes to decrease my risk.”
The Food and Drug Administration is concerned about the testing process. It has ordered 23andMe to stop the marketing and sales of its saliva collection home testing kit.
“They haven’t proven the clinical validity of the testing,” said Dr. Fuki Hisama, who runs the medical genetics clinic at the University of Washington School of Medicine. She’s skeptical of 23andMe and wants consumers to understand that genome testing is a complicated science.
“Our genome has three billion base pairs in it and that’s a lot of information and it takes a lot of specialty training, we think, to be able to order and understand a genetic test,” said Hisama.
She tells of a UW clinic patient recently who brought in the written results of her 23andMe home genetic test. It indicated no mutation of the BRCA gene for breast cancer. But a follow up, hospital-based genetic test revealed the opposite.
“So she actually has a mutation and she actually chose to do what Angelina Jolie did and do preventive surgery to prevent breast cancer, but she would not have learned that from the 23andMe test.”
Even worse, a patient could make a critical health care choice based on a potential false positive.
23andMe issued a statement:
“We recognize that we have not met the FDA’s expectations regarding timeline and communication regarding our submission. Our relationship with the FDA is extremely important to us, and we are committed to fully engaging with them to address their concerns.”
It’s one thing, said Hisama, to do the testing to learn about your ancestry. “But when it gets into the realm of medical information, diagnosing or predicting risk of diseases, that is difficult for a person to do at home and that is not advisable,” said Dr. Hisama.
A few years ago, clinics marketed full body scans, costing hundreds or thousands of dollars, as a way to screen for disease. At the time, the FDA emphasized a lack of data that the scans were particularly effective in early diagnosis of disease.
Dr. Jonathan Tait, director of the genetic testing lab at the UW Medical Center, agrees that the home genetic tests similarly prey on people’s fears that something bad is going to happen to them.
“The problem with these really broad brush tests, it’s the same thing as the body scans, is you’re going to turn up a fair amount of stuff that really doesn’t mean there’s any actual disease or actual risk, but will never-the-less get you worried once you find it out,” said Tait.
It’s true the home genetic tests are now affordable.
“But, in the end, if you end up with bad information and bad decisions, then the cost to you is going to be a lot more than what you paid for the test in the first place,” Tait reasoned. “Caveat emptor,” said Hisama. “Let the buyer beware.”
