This article is more than 5 years old. Information may no longer be current.
Newborn screening identified higher incidence of SCID
Click Here to Manage Email Alerts
Newborn screening for severe combined immunodeficiency detected the condition in 1 out of every 58,000 births.
This population-based rate was higher than the 1-per-100,000 figure previously calculated by retrospective clinical diagnoses.
Antonia Kwan, PhD, MRCPCH, a postdoctoral scholar at the University of California, San Francisco, and colleagues evaluated data from more than 3 million newborns screened with a T-cell receptor excision circles (TREC) test.
Representatives from screening programs in 10 states and the Navajo Area Indian Health Service contributed the data, which researchers used to identify the population-based incidence of severe combined immunodeficiency (SCID) and other T-cell lymphopenia conditions.
Results showed a combined 52 infants were diagnosed with SCID (n=42), leaky SCID (n=9) or Omenn syndrome (n=1), equating to an overall detection rate of 1 per 58,000 infants (95% CI, 1/46,000 to 1/80,000).
The incidence was comparable between programs in each the 10 states but was higher in the Navajo Nation (1/3,500; 95% CI, 1/630 to 1/4,000). Researchers attributed this higher incidence to the high rate of the
Forty-nine of the infants with SCID received immunity-restoring therapies: 44 underwent hematopoietic cell transplantation, four underwent gene correction and two received enzyme replacement. The SCID survival rate was 87% among all diagnosed infants and 92% among those who underwent treatment.
Newborn screening also identified 411 infants with non-SCID T-cell lymphopenia. One-third (33%) of those infants had a congenital syndrome associated with T-cell impairment. However, researchers noted T-cell cut-off definitions (˂1,500 T cells/microliter to ˂3,505 T cells/microliter) and follow-up (3/100,000 to 47/100,000) varied in this population across the screening programs.
“The TREC assay has proven excellent for detecting disorders with poor T-cell production or inadequate numbers of circulating T cells, but finding additional immune defects prior to onset of recurrent or life-threatening infections will require further methods,” Kwan and colleagues wrote.
Although these data suggest the promise of newborn screening for SCID, researchers must standardize the practice prior to implementation of nationwide screening, Neil A. Holtzman, MD, MPH, professor emeritus in the department of pediatrics at Johns Hopkins Medical Institutions, wrote in an invited commentary.
“Before screening becomes universal in the United States, agreement is needed on what constitutes a positive TREC screening test, on ensuring referrals to physicians competent to make a diagnosis and on providing definitive therapy to every infant detected with SCID in every state,” Holtzman wrote. “The technological advances in newborn screening since phenylketonuria screening was first recommended in the United States 50 years ago have been remarkable. However, organizational advances that ensure safe and effective newborn screening nationwide have not matched them.”
For more information:
Disclosure: The researchers report no relevant financial disclosures.