Newborn screening for SCID: the very first prospective pilot study from Türkiye

Area of Science:

• Immunology
• Genetics
• Public Health

Background:

• Severe combined immunodeficiency (SCID) is a group of rare genetic disorders.
• Newborn screening (NBS) using T-cell receptor excision circle (TREC) measurement in dried blood spot (DBS) samples is crucial for early SCID detection.
• Türkiye has not previously had a national SCID screening program.

Purpose of the Study:

• To report the results of Türkiye's first pilot newborn screening program for SCID.
• To assess the feasibility and utility of SCID screening in Türkiye.

Main Methods:

• TREC levels were measured using RT-PCR in 20,253 randomly selected DBS samples from newborns.
• Samples with low TREC levels underwent retesting and further DBS analysis.
• Confirmed SCID cases were identified through genetic analysis and clinical work-up.

Main Results:

• The initial TREC analysis identified 1.4% of newborns with low TREC levels.
• Follow-up testing confirmed SCID in 2 infants (0.049%), with confirmed ADA and RAG1 defects.
• The incidence of SCID in Türkiye was determined to be at least 1/10,000 live births.

Conclusions:

• The pilot study demonstrated the feasibility and usefulness of implementing SCID screening in Türkiye.
• Early detection through NBS allows for timely and curative treatment of SCID.
• This initiative can significantly improve outcomes for infants diagnosed with SCID in Türkiye.