April 18, 2011

Parents Want Predictive Genetic Testing For Their Kids

For some parents, the benefits of testing their children for the genetic risk of certain diseases will outweigh any negative consequences, a U.S. study found.

A study published in the May issue of Pediatrics found that parents who were offered genetic testing to predict their risks of common, adult-onset health conditions would most likely want to also test their children for the same health risks.

219 parents were offered genetic testing for susceptibility to eight common, adult-onset health conditions. These include colon, skin and lung cancer; heart disease; high cholesterol; and type 2 diabetes.

No children were tested in the study. Instead parents were asked a series of questions that compare the benefits such as reassurance, knowledge and prevention with risks that include invasion of privacy and psychological discomfort, reports BBC News.

The study found that the group of parents who were most interested in the test for themselves were the ones most interested in having the tests available for their child.

Parents in the study believed that the information found from the testing could help improve health maintenance, disease prevention, and other personal benefits during childhood and later in the child's life.

Predictive genetic testing in childhood for adult-onset conditions have been opposed by several professional organizations, since the information has not been shown to reduce disease or death through any interventions initiated early on in life.

Helen Wallace from genetic science lobby group Genewatch U.K. told BBC News, "Online gene tests frequently give misleading results because most common conditions such as cancer, obesity or diabetes are not predicable from a person's genes, except in special circumstances."

She goes on to say, "Children should not be tested for risk of adult-onset conditions, full stop. They should be allowed to decide for themselves, with medical advice, when they are grown up."

Presently, controversial personal genetic tests are available directly to consumers at drug stores and over the Internet. Usually these are marketed to adults for their own use; however, it is possible that over time, these testing kits will advertise to parents about testing it for their children, says Kenneth P. Tercyak, PhD, associate professor of oncology and pediatrics at Georgetown Lombardi Comprehensive Cancer Center. Tercyak is the lead author of the study.

"These tests usually don't offer a clean bill of health and can be hard to interpret even in the best scenario," he says.

"They identify incremental risks for many common diseases. Most people carry some risk based on a combination of their family history, genetics, and lifestyle.

A child's unexpected test results could trigger negative reactions among parents and children, and lead to conversations at the pediatrician's office that providers aren't prepared to have," says Tercyak.

Director of BMA Professional Activities Dr. Vivienne Nathanson says, "We would have concerns about genetic testing being widely available over the internet or off the shelf because parents could find out results without a health professional to help interpret them. They may also find out about genetic abnormalities for which there are no cures, or be caused needless worry."

She also says, "It is important that parents who find out that their children have a genetic disposition to a particular illness, have counseling in advance so they understand the consequences of the test for their child, other children and themselves."

"The findings of our study should remind clinicians and policy-makers to consider children when regulating genetic tests," Prof Tercyak says. "Genetic testing for common disease risk could usher in a new era of personalized medicine."

He says, "Someday, this type of information could help jump start conversations about lifestyle risks, and ways pediatricians can help parents and children reduce risk through healthier eating and exercise habits and avoiding tobacco and other substances. We still need to learn more about how to support families regarding choices on genetic tests and in adopting lifestyle changes, and what role high quality genetic information could play in those conversations."


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