The familiar heel prick that newborns receive is revealing more about a baby's health than ever before. But, as technology opens the possibility of screening newborns for hundreds of diseases, there is controversy over how much parents need to know.
Within days of an infant being born, a few drops of blood are taken from the baby's heel and tested for signs of more than two dozen different conditions, including congenital hypothyroidism and sickle-cell diseases. In many places, babies also are given tests to identify the likelihood of hearing or vision disorders.
Some states have expanded their checks, including testing for amino-acid and metabolism disorders. Many of the new conditions being looked at have no definitive treatment or it isn't clear whether immediate intervention is necessary. That can present an emotional dilemma for parents who may want to know if anything is wrong with their baby but in many cases have no therapy to pursue.
"The question is no longer whether we can test for them," says Alan Fleischman, medical director of the March of Dimes Foundation, "but what we want to know."
Newborn testing identifies at least 3,400 babies with a disorder each year, according to the Centers for Disease Control and Prevention. The programs generally have focused on well-understood medical conditions in which early intervention can make a difference in a baby's life. For example, the genetic disease phenylketonuria, or PKU, if left untreated, causes a protein to build up in the body and leads to brain damage. A special diet, including low-protein foods, can prevent it.
Proponents of broader screening programs say early intervention in a disease can improve a child's life and might speed the development of treatments for rare diseases, where symptoms often don't appear until severe damage has occurred. Often there are few specialists knowledgable about rare disorders, and newborn screening can save families years of anguish searching for a diagnosis. Some parents also say the information is important to know for family-planning purposes.
But critics say the additional tests may raise flags that lead to unnecessary further testing, or treatment, for babies who will not get sick. The tests can add big additional costs to the health-care system, they say. And some people are concerned about privacy, since stored blood-spot samples can be used by researchers. Some states give parents the ability to decide whether they want a child's specimens used for research purposes.
New York state tests newborns for Krabbe disease, even though federal health officials say the available treatment for the rare, often fatal, neurodegenerative condition—a stem-cell transplant—has a high mortality rate. And Illinois plans next year to begin testing for Pompe disease, a muscle-weakening disorder. Federal officials say it's hard to tell which infants need immediate treatment.
"Distinguishing between who will benefit and who will not is a phenomenally difficult issue," says Ellen Wright Clayton, director of the Center for Biomedical Ethics and Society at Vanderbilt University and a critic of the number of conditions for which babies are now screened. Newborn screening was set up to identify babies who can benefit from documented treatments, she says. "Anything else should be done as research," she says.
Most states offer screening for 29 major disorders recommended by the federal Secretary of Health and Human Services. Some states have mandated additional tests; babies in New York are screened for HIV. Many states, including California and Missouri, also tell families of any abnormal findings from tests for as many as 25 other conditions that aren't on the core list but that HHS thinks offer important health information.
The tests cost between about $20 and $120, depending on the state and number of conditions checked for, according to the nonprofit National Newborn Screening and Genetics Resource Center. For state-required conditions, the fees are usually paid by an insurer or Medicaid. Parents can also pay private labs to test for additional diseases.
An advisory board to the Secretary of Health and Human Services can suggest when new tests should be added, based on nominations from patient advocates, researchers or clinicians. Since 2005, HHS has agreed to add to its recommended list severe combined immunodeficiency disease, or "bubble boy disease," and is still considering whether to add a congenital heart condition.
One disorder turned down by the advisory committee was Krabbe disease. The committee said it worried about the difficulty identifying which children have the most aggressive form of the disease that requires immediate treatment. It also voiced concern that the available treatment, a stem-cell transplant, was invasive and has a high mortality rate.
Still, New York made screening for Krabbe-disease mandatory in 2006. A consortium of doctors developed a type of scorecard to determine which babies who test positive for Krabbe disease should receive an immediate stem-cell transplant. Babies are assigned points based on a combination of factors, including testing for an enzyme low in Krabbe patients and neurologic and other exams. If a child gets to four points, transplant is considered. The other babies are closely followed. Members of the consortium meet every six months to discuss each newborn who screens positive and to refine the scoring formula.
Patricia Duffner, a neurology and pediatrics professor at the University of Buffalo School of Medicine who organized the consortium, said more than a million babies have been screened for Krabbe disease in New York state in the past five years. She said health-privacy laws restrict her from providing information about the children.
But a report published last year by researchers from various institutions who reviewed the New York program said 25 newborns tested positive for Krabbe disease. Two of the children were considered at high risk for the disease but had not developed symptoms by 8 and 16 months of age. Two other children were diagnosed with Krabbe disease and were given stem-cell transplants. One died from complications of the transplant, the report said.
Cindy Parseghian, a mother of four children, three of whom died from the fatal cholesterol-metabolism disorder Niemann-Pick Type C, started a foundation together with her family that helps fund research efforts, including a project to develop a newborn screening test. Children with the disease are often treated with Zavesca, which is approved for a different genetic disorder. An experimental drug, cyclodextrin, is slated to go into an NIH trial in the coming year. In mice, both Zavesca and cyclodextrin are more effective at controlling the disease when given before symptoms appear.
Even without a cure for Niemann-Pick Type C, it is critical to find a way to diagnose children at birth if the drugs are going to make a difference, Ms. Parseghian, of Tucson, Ariz., says. Beginning work to develop a test for newborns now, she says, "will hopefully result in drugs and a screen being available at the same time."
First Checkup
Federal public-health officials recommend that all newborns should be screened for at least 30 possible diseases, although states can decide on their own which tests are required. Here are some disorders that babies are commonly checked for:
* Congenital hypothyroidism—a deficiency of thyroid hormones
* Cystic fibrosis—a genetic disease that makes it difficult to breathe
* Galactosemia—an inability to transform galactose into glucose, leading to blindness and other problems, sometimes death
* Congenital adrenal hyperplasia—a condition in which the adrenal glands fail to produce certain hormones, affecting growth and development
* Biotinidase deficiency—a disorder that can cause seizures, movement problems and sometimes death
Some states have added other newborn-screening tests, including ones that are controversial. A sampling:
* Krabbe disease— New York tests for this neurodegenerative condition, despite concerns by federal health officials over the difficulty of identifying which children would benefit from being treated with a stem-cell transplant.
* Pompe disease— Illinois plans next year to start screening for this progressive muscleweakening disorder caused by a buildup of glycogen. Infants with the most severe form can die from heart failure before their first birthday. Federal officials have raised concerns about difficulties distinguishing infants who need immediate treatment.
* Toxoplasmosis—New Hampshire and Massachusetts screen for this parasitic infection, which can lead to motor abnormalities and vision impairment. Some public-health officials have questioned if the disease occurs too infrequently to make it cost-effective to screen.
* Hemoglobin H disease— California screens for this condition, which can result in anemia. Federal officials have failed to recommend the test because of uncertainty over whether early identification improves a baby's health.
source: online.wsj
No comments:
Post a Comment