WASHINGTON — Rapid expansion and new technologies are changing the face of newborn screening in the United States, experts and policy makers agreed at the annual meeting of the American Association for the Advancement of Science.
Michael Watson, Ph.D., of the American College of Medical Genetics outlined the rapidity of change. In 2002, around 30% of newborns in the United States were screened for fewer than 5 conditions, and only 5% for 20 or more. By October 2004, closer to 20% of newborns were screened for fewer than 5 conditions, and 27% were being screened for more than 20 conditions.
Only three conditions—phenylketonuria, galactosemia, and congenital hypothyroidism—are screened universally.
Tandem mass spectrometry in particular is driving an increase in the number and kind of diseases tested for, and it is changing the nature of state-run testing facilities, as outlined in a series of presentations at the meeting.
“There are very few things in medicine that are universal. Newborn screening is one of them. Hardly anyone slips through this net. But states vary enormously in what they screen for,” said Duane Alexander, M.D., director of the National Institute of Child Health and Human Development.
Because of this disparity, and the conviction that newborn screening has achieved only a fraction of its potential, the Advisory Committee on Heritable Disorders and Genetic Diseases in Newborns and Children was established in 2003.
The committee was authorized by Section 1111 of the Children's Health Act of 2000 to provide recommendations for a uniform panel of screening, and decision-making tools for the states to use in evaluating the future development of screening. Part of the committee's charge is to provide advice and recommendations on the funding of grants to the states for the improvement and/or expansion of newborn screening, as outlined in Section 1109 of the act.
The final report of the American College of Medical Genetics committee on the 78 conditions analyzed by the panel is available for public comment, and the secretary of Health and Human Services will evaluate it. Overall, the committee is recommending routine screening of 29 of the disorders considered, Dr. Watson said
According to Dr. Watson, the committee has already been having an effect on the evolution of newborn screening by its preliminary meetings, and its recommendation for screening 20 metabolic disorders with tandem mass spectrometry (MS).
Currently, more than half the states have instituted mandatory tandem MS screening, with several more having pilot studies or optional testing available, he said.
Tandem MS provides a complex profile of the metabolic status of an infant's blood sample. It is capable of simultaneously analyzing most compounds in a sample, giving both identification as well as concentration information. This can include information for diseases not mandated for screening by a particular program, as well as information on conditions that have no treatments, or ones that may have privacy implications.
“Having already determined that tandem MS ought to be part of a newborn screening program, we now are left with all of those other conditions that fall out of an MS profile,” Dr. Watson said. The committee has advocated the release of all clinically relevant data to practitioners and patients, regardless of the purpose of the initial screening.
Ultimately, newborn screening is likely to move into the genomics age, said James Hanson, M.D., of the NICHD. He suggested that, in future, DNA chips, proteomics, nanotechnology, and a variety of biophysical approaches will likely become part of this process. Luckily, for the easy evolution of screening, the standard heel-stick blood spots currently obtained are also appropriate for the majority of the new technologies.
Unfortunately, part of the long-term problem with the evolution—and cost—of newborn screening techniques involves competition from other forms of screening, such as for prostate cancer in adult men, and breast cancer in women. At some level, all these new screening methods inevitably compete for resources, Dr. Hanson said.
“Truth of the matter is, there is not enough money in the health care system the way it's applied for children at the present time to allow us to spend all we would like for every patient or child with a rare disorder,” Dr. Hanson said. “It is deplorable from an ethical standpoint but is a practical reality at the present time.”
Such cost considerations are likely to increase as screening proliferates. According to Piero Rinaldo, M.D., a pediatric geneticist at the Mayo Clinic, Rochester, Minn., there are also moves to expand screening beyond the newborn stage to capture disorders such as Wilson's disease—a hereditary disorder that causes copper to build up to toxic levels—and congenital disorders of glycosylation, none of which are detectable until later in an infant's life.