Newborn Screening for SCID: The very first prospective pilot study from Turkey

Abstract Purpose: The measurement of T-cell receptor excision circle (TREC) is being used in newborn screening (NBS) for severe combined immunodeficiency (SCID). Here, we report the results of newborn screening pilot program for SCID conducted in Turkey.Methods: The study was carried out together with Ankara University School of Medicine and The Ministry of Health (Public Health General Directorate and Pediatric and Adolescent Health Department). TREC measurements were performed in randomly selected Guthrie card samples obtained from 20.253 babies born between October 2018 and October 2020. The TREC analyses were performed together with beta Actin (β-Actin) via RT-PCR (Real Time Polymerase Chain Reaction) Results: TREC copy numbers found normal in 98.6% of the newborns (n: 19.975) at the initial analyses. Two among 10 babies who had undetectable TREC copies diagnosed as SCID; ADA and RAG1 defects confirmed respectively in the first (NB1/P1) and the second (NB2/P2) baby. They both received curative treatments (gene therapy and HSCT) free from live vaccines and life-threatening infections occurred. The remaining 6 of 8 newborns who had low (< 46 copies/DBS and <15 copies/µl) TREC copy numbers found normal following clinical and laboratory work-up while medical records related to other two reveled early postnatal death due to extreme prematurity. Conclusion: In the light of this study the incidence of SCID was detected at least 1/10.000 live births in Turkey. Finally, it is quite clear that SCID should be included as early as possible into the national NBS program in Turkey.