Their First Test
Newborn screenings—frightening for some parents—can help save a child’s life
In those first whirlwind hours in the hospital with a newborn, few parents pay careful attention to their child’s newborn screening. If they do, they might view the screening’s requisite heel prick and squeezing for blood with annoyance—just one more thing to make their baby cry.
That’s how Texas parents Mark and Janna Thomas felt until the birth of their third child, Hayley. Hayley had a “normal, easy birth,” Janna says, and appeared perfectly healthy. But the newborn screening showed Hayley had a rare, inherited enzyme deficiency, called homocystinuria, which prevents the body from breaking down a certain type of protein. If left untreated, the disorder could kill her, or cause brain damage. The screening likely saved Hayley’s life, say her parents.
“We feel very lucky,” Janna says. Immediately after the diagnosis, Hayley began taking a special low protein diet. She will have to follow it for the rest of her life. “We hate the diagnosis, but are so glad it was found.”
Race against time
If Hayley were born just six years earlier, she would not be so lucky. In February 2007, Texas expanded the number of diseases on its screening. Homocystinuria was one of the new diseases included on the panel. The Texas Department of State Health Services (DSHS) Newborn Screening Program now covers 29 incurable, and often life-threatening disorders (see below for listing).
Once a disorder is detected, early treatment is critical. Like Hayley, most children born with disorders covered by the screening appear normal at birth. However, these conditions can progress quickly, “some of them within days,” says Hope Northrup, MD, professor and director of Medical Genetics in the Department of Pediatrics at The University of Texas Health Science Center at Houston (UTHealth) Medical School. She says babies may look normal one moment, but slip into coma hours later. “So for some of them (patients), death can be the outcome, or severe neurological devastation.”
UTHealth Medical School’s Division of Medical Genetics is one of six recognized metabolic referral centers for the DSHS. Since the expansion of disorders covered by newborn screening, Northrup says she and her team have diagnosed and treated many patients who would have otherwise died.
“We have prevented not only their deaths, but also likely damage by diagnosing them early, getting them on the proper dietary intervention, giving them proper supplements and following them to prevent crises that would have severely damaged their brains and killed them,” she adds.
Testing varies from state to state
Newborn screening laws differ across the United States. Some states screen once, some twice, and each state screens for different disorders—although all states now screen for the 26 disorders recommended by the American College of Medical Genetics. To put the expansion of newborn screening in perspective, in 2003, all but four states screened for only six of these disorders.
By law, all babies born in Texas are screened twice, unless parents refuse for religious reasons.
In Texas, the first screen happens in the hospital 24 to 48 hours after birth. A healthcare professional, often a nurse, takes a small amount of blood from the baby’s heel, puts it on an absorbent paper, and sends it to the DSHS laboratory for testing. The second blood sample is taken one or two weeks later, usually at the baby’s first checkup.
Two screenings are necessary because the first screen may be a false positive, or the disorder may be detected only on the second screen.
“The false positive rate is extremely high, and the reason it is very high is because we don’t want to miss any true positive,” Northrup says.
If the screening comes back positive, the DSHS contacts staff at the hospital or the patient’s pediatrician, who in turn will contact the parents. The next step is additional testing in the pediatrician’s office or at a metabolic referral center to confirm or rule out the results of the screen. Once the diagnosis is confirmed, a team of specialists from the metabolic referral center develop a treatment plan.
Diet key to treatment
Many of the diseases identified by the screening are metabolic disorders, caused by an enzyme deficiency. The lack of an enzyme causes metabolites that are toxic to cells to build up in the body, or prevents the body from producing a substance that it needs. Patients with these diseases are often treated with a special diet.
Phenylketonuria, or PKU, is one of the better known of these disorders, and was the first to be screened for in Texas beginning in 1965. Patients with PKU lack the enzyme that breaks down phenylalanine, an amino acid that is part of protein found in the majority of food. Too much phenylalanine damages the central nervous system and causes brain damage. Patients with PKU need to be on restrictive diets for their entire lives.
“It is a balancing act between keeping them safe and helping them grow,” says Heather Saavedra, MS, RD, LD, a nutritionist with the Division of Medical Genetics in UTHealth Medical School’s Department of Pediatrics. She works closely with families to develop a diet plan that fits into their everyday lives and helps monitor their child’s amino acid levels.
Like PKU patients, Hayley also lacks an enzyme to breakdown protein, but a different protein called methionine, which causes homocysteine to build up and damage the nervous and vascular system.
To keep her homocysteine levels under control, Hayley drinks a specially modified formula (which costs $500 a month and is not covered by her insurance*). Her parents also carefully measure the foods she eats. She is allowed only a certain amount and type of protein each day. Meat, dairy, eggs, beans and nuts are off limits, as well as energy bars and anything high in protein. Keeping Hayley on her strict diet takes constant effort, says Janna, and will be more difficult as she gets older.
“It is not going to be easy,” she says. “My son gave her a Nutrigrain bar one day. She took a bite of it. She can’t have some of the stuff that he eats. But she is going to be as normal as she can be.”
“It makes such a difference”
Patients like Hayley are living examples of the promise of newborn screening, Northrup says. Without newborn screening their disease would go undiscovered, causing severe damage to the brain and body, even death. Newborn screening gives patients with genetic diseases a chance at a normal life. Still, some critics say the newborn screening unnecessarily frightens parents.
“It (newborn screening) is difficult for new parents,” empathizes Joanne Nguyen, MD, a proponent of newborn screening and assistant professor of pediatrics at UTHealth Medical School. Nguyen is Northrup’s medical partner. “You have a new parent, and a new baby, and sometimes they don’t even know that they have had this test done. And you are telling them that they have had an abnormal test result, so it is challenging.”
Northrup agrees that the uncertainty involved with newborn screening can be hard on parents, but asks for their patience. “It is definitely worth it to find the ones that do (have genetic disorders),” Northrup says. “Because it makes such a difference.”
Newborn screening is an enormous endeavor for a state like Texas, which has an estimated 400,000 births a year. Because of the double screen, the DSHS processes an estimated 800,000 blood specimens a year. Of that number, 15,000 samples come back abnormal. Approximately 600 cases are confirmed as disorders each year.
“It is a huge undertaking to check all the babies, but it is cost effective and worth it.” Northrup says. She adds that early diagnosis prevents costly complications. Because of its impact, the Centers for Disease Control and Prevention named newborn screening programs one of the top 10 public health achievements of the first 10 years of the 21st century.
Northrup says the prognosis of children with PKU is a good example how newborn screening benefits public health. In the past, PKU was a leading cause of intellectual and developmental disabilities, and children with PKU were institutionalized because of their severe retardation.
“Now we diagnose patients with PKU with newborn screening and they are just like everyone else,” she says. “They grow up, they get married, they go to college and they have kids. They get to have a normal life.”
* A state mandate requires that companies offering insurance in Texas cover medical foods (specially modified formulas), but if a company has a self-insured plan, they are exempt from this requirement.
The Thomas family encourages readers who would like more information about taking care of a child with homocystinuria to contact them at Mark.Thomas@us.endress.com.comments powered by Disqus
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