Variables of Testing Baby

“Few new parents give even a passing thought to how thoroughly their resident state screens newborns for congenital disorders.
Typically, screening tests get parents’ attention only in the rare case of an abnormal result — which, because of the false positives common with such tests, may not necessarily mean their baby has a problem. Further testing is needed for a definitive answer.
About 15,000 to 19,000 of the 4 million U.S. babies born each year have a treatable condition for which a screening test is available, says Jennifer Howse, president of the March of Dimes. Howse’s organization today released its annual “report card” tallying screening tests offered by each state.
“These are rare disorders,” Howse acknowledges. “But if it’s your baby, then it’s the world.”
Thanks to a relatively new technology called tandem mass spectrometry, the number of disorders that can be detected in newborns — still with just a few drops of blood taken by a heel stick — has greatly expanded. In many cases, early detection and treatment can mean the difference between life and death, between profound disability and normal mental and physical development.
But as with many technological advances in medicine, tandem mass spectrometry has not only answered questions, but has raised some as well. For example, just because you can screen for a congenital abnormality, should you? And should you bother to pay a private company to augment screening provided by your state?
“Once you have tandem mass spectrometry, Pandora’s box is open,” says Susan Panny, medical director of Maryland’s newborn screening program. Before it became available, she says, “you didn’t screen for things that didn’t make people sick, even though they were not quite normal. Now, I think, there are no guidelines whatsoever. I think people think if you can find it, you ought to do it.”
What should be tested?
A report released in March by the American College of Medical Genetics and endorsed by the March of Dimes and the American Academy of Pediatrics recommends that all U.S. newborns be screened for hearing loss and 28 other “core” conditions using the heel stick. So far, only Mississippi screens for all 29, the March of Dimes says.
Twenty of the conditions are rare metabolic disorders, such as maple syrup urine disease. The others include a variety of inherited conditions, such as cystic fibrosis and sickle cell disease. They were selected because they can be detected in newborns with an accurate screening test and treated, says Howse, who served on the report’s steering committee. Tandem mass spectrometry can screen for about two dozen other disorders for which no treatment is available, according to the March of Dimes.
The list of 29 core conditions is not without controversy. “It’s not a perfect list,” says Richard Parad, a newborn specialist at Boston’s Brigham and Women’s Hospital. “There are many, many disorders on that list that are so rare they’re unlikely to happen.”
And in the case of one, a metabolic disorder known as MCAD, even children who do inherit it may never develop symptoms, Parad says. They go undiagnosed until a newborn screening picks up MCAD. “The diseases are just getting more complicated than they used to be,” Parad says. “It doesn’t mean we shouldn’t do (screenings for) them. It means we have to think about them a lot harder before we add them to the list.”
Diet makes all the difference in PKU, or phenylketonuria, the first condition for which newborn screening was developed more than 40 years ago.
Babies with PKU can’t process a part of protein called phenylalanine. Untreated, PKU causes mental retardation. But babies who are immediately put on a phenylalanine-free formula, followed by a special low- phenylalanine diet — no high-protein foods — through adolescence will have normal intelligence.
PKU remains the only metabolic disorder for which every state mandates newborn screening. Congenital hypothyroidism, sickle cell disease, beta thalassemia and glactosemia are the only other conditions for which every U.S. newborn is screened, according to the March of Dimes.
Whether your newborn will be screened for the other core conditions depends on where you deliver. For example, while Mississippi mandates screening for all 29, neighboring Louisiana requires screening for only 13, the March of Dimes says.
Using commercial screeners
People should find out what their state screens for, Howse says. If desired, they can pay for supplemental screening by a private provider. At least three for-profit labs are trying to fill in the gaps. In some states, the company Pediatrix has contracts with hospitals to provide expanded newborn screening.
Pediatrix also has begun advertising in parenting magazines and on Google, spokesman Bob Kneeley says. Expectant parents can order the “StepOne Newborn Screening Packet” from Pediatrix for $89, plus $6.35 for overnight return shipping to the company’s lab.
If a problem is detected, a Pediatrix genetics counselor calls the baby’s pediatrician to explain what the disorder is and what steps need to be taken, Pediatrix vice president Gail Lim says.
But the recent American College of Medical Genetics report suggests that newborn screening shouldn’t be left up to private laboratories: “Newborn screening is more than testing. It is a coordinated and comprehensive system consisting of education, screening, follow-up, diagnosis, treatment and management.”