Table 1:

Non–SCID conditions that may lead to an abnormal T-cell receptor excision circle–based newborn screen for SCID (10), (23), (31) (36)

Non-SCID causes of T-cell lymphopeniaExamples
Syndromic disorders and congenital abnormalitiesTrisomy 18
Trisomy 21
DiGeorge syndrome
CHARGE syndrome
Ataxia–Telangiectasia syndrome
Secondary T-cell lymphopeniaCardiac or gastrointestinal anomalies
Multiple congenital anomalies
Neonatal leukemia
T-cells losses into third space (e.g., hydrops or vascular leakage)
Prenatal exposure to purine antagonists
Preterm birth
Idiopathic T-cell lymphopenia
Combined immunodeficiencies with dysfunctional T cellsDOCK8 deficiency
Wiskott–Aldrich Syndrome
  • Note: SCID = severe combined immunodeficiency.