April 18, 2011 -- Tests that reveal children’s genetic risks for common diseases may soon become a popular choice among parents, even though the usefulness of the tests remains in question, according to a new study in the journal Pediatrics.
The increasingly popular tests are often marketed as a means to motivate people to make lifestyle changes to prevent the onset of diseases for which the tests show they are at risk. But there’s no evidence to back such claims. The tests are available over the counter and on the Internet.
“This is a new frontier for health care providers and for families,” says study author Kenneth P. Tercyak, PhD, associate professor of oncology and pediatrics at Georgetown Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center in Washington, D.C. “It’s an open question on how they will be incorporated into a primary care setting.”
But as the popularity and proliferation of the tests continue to grow, the study authors predict more pediatricians will be called upon to interpret the results of such tests, informing parents of their child’s risks for diseases such as diabetes, high blood pressure, and different types of cancer. That new role could be problematic.
“This is not something that most pediatricians are trained for, and, frankly, it could be a huge problem,” says Marshall L. Summar, MD, chief of genetics and metabolism at Children’s National Medical Center in Washington, D.C. “We’re trying to figure out how to gear up.”
Genetic Testing: How Useful?
Tercyak and his team of researchers surveyed 219 parents who were participants in a project funded by the NIH’s National Human Genome Initiative. In addition to being offered the opportunity to be tested for their own genetic risk for common diseases, parents were asked whether they would be interested in having their child tested. They were also asked how well they understood the risks and benefits of such testing.
The researchers found that parents who opted to take the tests themselves were more likely to be willing to have their children tested, especially if they anticipated a positive outcome.
“Parents certainly appreciated the upside and downside, but they weighed the upside more heavily,” Tercyak says.
Tercyak points out that other factors besides genetics must be weighed when considering a person’s risk for certain diseases.
“The environment can be more important than genes,” he says. “Disentangling the two over the life course is still a puzzle.”
And, according to the National Human Genome Research Institute, not enough is known about the role of genes -- and their interaction with lifestyle and environment -- to make reliable use of predictive genetic tests.
“This means that today's tests may falsely reassure people with undiscovered risk factors, or needlessly alarm people with undiscovered protective factors,” the Institute’s web site states.
Summar, who was not involved in the study, predicts that over the next five to 10 years, the number of available tests will increase dramatically. He also says that over that same period their validity will likely become much better established. Until then, at least, he is not advising parents to make use of them.
“Parents want the best things for their children,” Summar says, “but these tests are not yet at a level where they can address the health of their children.”