Studies show benefits of newborn screening for 'bubble boy disease'

December 19, 2005

Two new UCLA studies show that newborn screening for Severe Combined Immunodeficiency (SCID) -- a rare, treatable disorder of the immune system commonly known as "bubble boy disease" -- is both cost-effective and could be done accurately using a two tiered testing method.

"We wanted to determine whether testing for SCID should be added to the universal screening panel for genetic disorders," said Dr. Sean McGhee, clinical instructor of pediatric immunology at Mattel Children's Hospital at UCLA. "Treatment is now advanced enough that 95 percent of children can be cured, but newborns must be detected in the first month, before the onset of severe infections."

In the first study -- detailed in the November edition of the Journal of Pediatrics -- UCLA researchers concluded that SCID screening could result in a large benefit to infants, making screening relatively cost-effective in spite of the low incidence of the disease. However, an adequate test would be critical to cost-effectiveness.

The analysis is the first of its kind to examine formally cost and benefits of SCID newborn screening.

To conduct the study, researchers used information about the costs of diagnosing and treating SCID and the benefits of early diagnosis, and performed a cost-benefit analysis comparing universal screening with screening only those with a family history of SCID.

Researchers determined that a SCID screening test that cost less than five dollars with a false-negative rate of 0.9 percent and a false-positive rate of 0.4 percent would be considered cost-effective by most currently accepted standards.

A nationwide screening program would cost an additional $23.9 million per year for screening costs, but would result in 760 years of life saved per year of screening.

In a related pilot study -- described in the December edition of Molecular Genetics and Metabolism -- McGhee and his colleagues looked at using a "two-tiered" strategy to improve the accuracy of SCID screenings.

"Existing tests for SCID are pretty good by themselves, but they do not provide sufficient accuracy in diagnosing the disorder to make them cost-effective," McGhee said. "We wanted to see if combining the two tests would limit the false positive results."

The current basis for the screening test is measurement of the number of lymphocytes at the time of birth that are normally very high, but very low in SCID infants. The screening is done by using dried blood samples obtained for other newborn screenings.

In the retrospective analysis, investigators measured serum or plasma levels of interleukin-7 (IL-7), a T-cell growth cytokine elevated in SCID, in combination with the previously developed T-cell receptor recombination excision circles assay.

They found that combining the tests in a two-tiered strategy decreased the false positive rate to nearly zero, which would be sufficient to allow cost-effective screening.

McGhee added that this strategy should be addressed in a multi-center, prospective trial to determine accurately the incidence, specificity, sensitivity and cost of SCID newborn screening.

The incidence of SCID is unknown but may be more common than published estimates because infants frequently die of infection before diagnosis. If an infant is diagnosed -- preferably within the first month of life -- and before their first infection, most can be treated with a bone-marrow transplant. About half of the patients can be cured; the other half may require intravenous immune globulin therapy treatments, but can live normal lives.
Other UCLA authors on both studies included Dr. E. Richard Stiehm and Dr. Edward McCabe. In addition, Dr. Morton Cowan, University of California, San Francisco, and Dr. Paul Krogstad, UCLA, co-authored the study on the two-tiered universal newborn screening strategy.

Support for all research was provided by the human and molecular development training grant at the David Geffen School of Medicine at UCLA, NIH/NICHD and the Culpepper Biomedical Pilot Initiative of the John D. Rockefeller Foundation.

McCabe is an adviser to GeneFluidics, a nanotechnology company involved in genetic testing.

University of California - Los Angeles

Related Newborn Screening Articles from Brightsurf:

Expanded newborn screening could save premature infants' lives
Expanding routine newborn screening to include a metabolic vulnerability profile could lead to earlier detection of life-threatening complications in babies born preterm, according to a study by UC San Francisco researchers.

Genomic sequencing as a standalone newborn screening tool falls short
With the rise of genomic sequencing, health technology companies are promising parents they can detect rare metabolic disorders in newborns who, despite a healthy appearance, may need immediate treatment.

Mailed colorectal cancer screening kits may save costs while increasing screening rates
New research indicates that mailing colorectal cancer screening kits to Medicaid enrollees is a cost-effective way to boost screening rates.

Stakeholders update newborn screening guidelines for critical congenital heart disease
A distinguished panel of medical experts, state and federal health officials, and congenital heart disease parent advocates published recommended updates to the current American Academy of Pediatrics' protocol for detecting critical congenital heart disease (CCHD) in newborn babies using pulse oximetry.

Spinal muscular atrophy (SMA): Newborn screening promises a benefit
The earliest possible diagnosis and treatment of infantile SMA through newborn screening leads to better motor development and less need for permanent ventilation as well as fewer deaths.

How newborn stars prepare for the birth of planets
An international team of astronomers used two of the most powerful radio telescopes in the world to create more than three hundred images of planet-forming disks around very young stars in the Orion Clouds.

Newborn baby hiccups could be key to brain development
Each time a newborn baby hiccups, it triggers a large wave of brain signals which could help the baby learn how to regulate their breathing, finds a new UCL-led study published in Clinical Neurophysiology.

Reducing seizures by removing newborn neurons
Removing new neurons born after a brain injury reduces seizures in mice, according to new research in JNeurosci.

Delaying newborn baths increases rates of breastfeeding
While it has been standard practice for decades to whisk newborns off to a bath within the first few hours of their birth, a new Cleveland Clinic study found that waiting to bathe a healthy newborn 12 or more hours after birth increased the rate of breastfeeding exclusivity during the newborn hospital stay.

'Multiomics' and the newborn mouse heart
The heart of a neonatal mouse is capable of self-repair after tissue damage.

Read More: Newborn Screening News and Newborn Screening Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to