Newborn screening New technology revives old controversy

In 1961, Robert Guthrie developed a method to test newborns for phenylketonuria, or PKU - a genetic disorder that prevents the body from processing a protein found in almost all food, causing severe mental retardation.

Now using just one drop of blood, about 4 million newborns in the United States undergo testing each year for PKU, as well as a number of other genetic diseases including sickle cell disease and cystic fibrosis through state newborn screening programs. And promising new DNA-based technology is on the horizon that will greatly expand the medical community's ability to detect even more genetic abnormalities in newborns.

While new technology has increased the ability to detect genetic diseases in newborns, it also has rekindled much of the debate that has plagued newborn screening for more than 40 years - lack of federal mandates for testing, the costs of long-term treatment for children who test positive for a genetic disorder, and testing for diseases that may have a potential treatment but no cure, among others.

In a paper published in the August issue of the Archives of Pediatric & Adolescent Medicine, lead author Beth A. Tarini, M.D., clinical lecturer and member of the Child Health Evaluation Research Unit at the University of Michigan C.S. Mott Children's Hospital, outlines the controversies surrounding newborn screening, and provides insight into the issues that must be addressed for the continued success of this public health screening program.

"Given the rapid pace of technological advancements, we must make clear and informed decisions about how we implement new technology in state newborn screening programs," notes Tarini. "Many questions remain about screening uniformity and how best to coordinate follow-up evaluation for positive newborn screening tests."

Although newborn screening is mandated by all 50 states, genetic conditions screened and testing methods used often vary from state to state. Some states test for the 29 conditions recommended by the American College of Medical Genetics.  Other states, including Michigan, test for more than 40 conditions, Tarini says.

"Uniformity with newborn screening is key in terms of assuring equal access and establishing a standard of care," says Tarini. "But then the issue becomes how high do you set the bar? Do you only test for 29 genetic disorders, or should newborns be tested for 40?"

New technology is pushing these issues to the forefront. With only one drop of blood, tandem mass spectrometry - a technology that medical experts first applied to newborn screening in the 1990s - can detect at least four times more disorders than previous testing techniques.

Another recently developed technological advance - DNA microarray - offers the potential to continue to broaden newborn screening by making it possible to test for hundreds of potentially disease-causing genetic mutations.

But the process of newborn screening involves more than just the initial blood test. A successful public health screening program is not complete without proper follow-up care, and should include a systematic collection of long-term data to advance medical research and treatment of genetic disorders, says Tarini.

"In our society, technology drives us - and medicine is no different.  However, healthcare providers and public health officials are in a position to make decisions about how we implement technology in a way that maximizes health benefits for the child, and minimizes any harm, even if it is unintentional," she says.

To ensure the continued success of newborn screening, Tarini says there needs to be improved communication between health care providers and parents prior to and following screening, as well as coordination of care between primary care physicians and genetic experts for infants with positive screening results.

Another issue being debated in the medical community is whether or not to test for diseases for which a cure or consistently effective treatment may not be available. A recent report from the C.S. Mott Children's Hospital National Poll on Children's Health that looked at this issue found that 54 percent of adults endorse genetic testing to determine if their child is at increased risk for developing a disease, even when no effective treatment exists.

"Some experts believe that we should not test children for conditions for which no effective treatment exists. On the other hand, some parents feel that knowing that their child has a condition helps families to prepare for their child's illness, even if a cure or effective treatment is not available," says Tarini.

Reference: Archives of Pediatric and Adolescent Medicine, Aug. 2007, Vol. 161, No. 8.

Written by Krista Hopson

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