AbstractSevere combined immunodeficiency (SCID) is a life-threatening disease characterized by a disturbed development of T and B cells. SCID can be screened by measuring T-cell receptor excision circles (TRECs), a marker of normal T lymphopoiesis. Newborn screening (NBS) for SCID has already been initiated in several countries to save 1 in 60,000 newborns carrying this disease.
In the initial year a total of 22,865 infants were enrolled in this study. They account for 65.6% of all births in participating hospitals and suggesting the acceptability of this test by parents. The median TREC copy number was 136 (range: 0–2,330) copies/μL. Fifty (0.22%) infants showed a low TREC copy number, which was below the cut-off value.
These infants were referred for flow cytometric analysis and comprehensive genetic analysis for primary immunodeficiencies. Non-SCID T cell lymphopenia are found in 9 infants. Among these, One is DiGeorge syndrome with severe lymphopenia. He received prophylaxis for infection. Others are Down syndrome, gastrointestinal anomalies, and chylothorax.
This is the first large-scale NBS for SCID in Japan through which we would be able to confirm the feasibility of NBS for SCID in our country.