title: Neonatal Levels of T-cell Receptor Excision Circles (TREC) in Patients with 22q11.2 Deletion Syndrome and Later Disease Features.
abstract: OBJECTIVE
  Newborns with severe T-cell lymphopenia, including those with 22q11.2 deletion syndrome (DS), have low numbers of T-cell receptor excision circles (TRECs). The aim of this study was to determine a possible correlation between neonatal TRECs in 22q11.2DS and the development of different phenotypes to elucidate the prognostic value of TREC in this disease.
  
  
  METHODS
  In this national survey including 46 patients with 22q11.2DS born after 2005, TREC levels were determined using stored newborn screening blood spots on filter cards. Patients were grouped into quartiles according to their TREC values, except the two infants with thymus aplasia.
  
  
  RESULTS
  The two patients with thymic aplasia had no detectable TREC. The rest had no severe clinical immunodeficiency. There was a significant correlation between low TRECs and the proportion of patients with CD3(+)CD4(+)T-cells below the 5th percentile of healthy infants (p = 0.027) as well as the proportion with an abnormal thymus feature either no thymus or remnant thymus as observed during heart surgery (p = 0.022). Significantly lower TRECs (p = 0.019) were found in patients with cardiac defects compared to no such defects. Patients within the lowest quartile of TREC values (<71 TRECs/μL, n = 11) had more frequent severe cardiac defects than the other quartiles (p = 0.010). Eight of these patients in the lowest quartile needed an operation/intervention within two weeks after birth or died because of a cardiac defect.
  
  
  CONCLUSIONS
  The low TREC values not only correlate with decreased T-cell immunity, but also with the occurrence of heart defects in the patients.
authors: Department of Pediatric Research, Women and Children's Division, Oslo University Hospital Rikshospitalet, Oslo, Norway, Kiran.aftab.gul@rr-research.no.
authors: Kiran A
authors: KA
authors: Gul
authors: Torstein
authors: T
authors: Øverland
authors: Liv
authors: L
authors: Osnes
authors: Lars O
authors: LO
authors: Baumbusch
authors: Rolf D
authors: RD
authors: Pettersen
authors: Kari
authors: K
authors: Lima
authors: Tore G
authors: TG
authors: Abrahamsen
mesh_terms: D002872:Chromosome Deletion; D004270:DNA, Circular / Q000097:blood / Q000235:genetics*; D004062:DiGeorge Syndrome / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D006330:Heart Defects, Congenital; D006801:Humans; D016130:Immunophenotyping; D007231:Infant, Newborn; D007239:Infections / Q000209:etiology; D008297:Male; D009929:Organ Size; D011948:Receptors, Antigen, T-Cell / Q000097:blood / Q000235:genetics*; D016176:T-Lymphocyte Subsets / Q000378:metabolism*; D013950:Thymus Gland / Q000473:pathology
chemical_list: D004270:DNA, Circular; D011948:Receptors, Antigen, T-Cell