Severe combined immunodeficiency (SCID) disorders may be detected, in newborn screening programs, using quantitative PCR assays to measure T-cell receptor excision circles (TRECs), a byproduct of correct T-cell development. However, in addition to SCID patients, other T-cell deficient phenotypes such as 22q11.2 deletion syndrome (DS), 22q11.2 duplication syndrome, CHARGE syndrome and trisomy 21 are being detected
We present our experience with the detection of 22q11.2 DS and duplication syndrome in a series of 103,971 newborns screened within the newborn screening program in Catalonia (Spain) since January 2017.
Nineteen positive cases were detected (low TRECs) and 5 cases turned out to be copy number variations (CNVs) of the 22q11 region when investigated with array CGH technology (four deletions and one duplication). 2 cases were diagnosed prenatally while the remaining 3 newborns were diagnosed postnatally due to persistent low TRECs levels and mild lymphopenia (not fulfilling SCID criteria) despite being asymptomatic.
Newborn screening for SCID allows the detection of other entities, such as 22q syndrome which unexpectedly should be included in a prompt proactive follow-up and an adequate management of information and expectations for the families by a multidisciplinary team