title: Incidence of severe combined immunodeficiency through newborn screening in a Chinese population.
abstract: OBJECTIVE
  In order to know the true incidence of severe combined immunodeficiency (SCID) in a Chinese population, we conducted and implemented SCID newborn screening in Taiwan.
  
  
  METHODS
  Between May 1, 2010 and December 31, 2011, the National Taiwan University Hospital Newborn Screening Center screened all newborns for T-cell lymphopenia by measuring the copy number of T-cell receptor excision circles (TRECs) and RNase P. Newborns with low TREC values were subjected to complete blood cell counts and flow cytometry.
  
  
  RESULTS
  A total of 106,391 newborns were screened using the TREC assay over a period of 19 months. Five newborns were immediately referred for confirmatory tests, including two SCID patients and two patients with persistent T-cell lymphopenia; a third SCID patient was found 2 months after the study period. All three SCID cases received stem cell transplantation at the age of 2-5 months. We also identified five cases of 22q11.2 microdeletion syndrome. During this period, two SCID patients from among the unscreened newborns were reported, and they died at ages 3 months and 4 months, respectively.
  
  
  CONCLUSIONS
  Newborn screening to measure the number of TREC copies successfully identifies newborns with T-cell lymphopenia, 22q11.2 microdeletion syndrome, and other high-risk conditions. Taken together, the incidence of T-cell lymphopenia in apparently healthy newborns is more than 1 in 11,821, and further attention to their immune functions is warranted.
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yin-Hsiu
authors.initials: YH
authors.lastname: Chien
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Chiang
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Kai-Ling
authors.initials: KL
authors.lastname: Chang
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hsin-Hui
authors.initials: HH
authors.lastname: Yu
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital and Children's Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Wen-I
authors.initials: WI
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Buddhist Tzu Chi General Hospital, Taipei Branch, New Taipei City, Taiwan.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Tsai
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Hsu
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Min-Huei
authors.initials: MH
authors.lastname: Hu
authors.affiliation: Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan; Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: hwuwlntu@ntu.edu.tw.
authors.forename: Wuh-Liang
authors.initials: WL
authors.lastname: Hwu
mesh_terms: D044466:Asian People; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000453:epidemiology*; D008297:Male; D015997:Neonatal Screening; D016511:Severe Combined Immunodeficiency / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology
keywords: T-cell receptor excision circles; TRECs; newborn screening; severe combined immunodeficiency disease