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Complete DiGeorge anomaly in the absence of neonatal hypocalcemia and velofacial and cardiac defects
Salem Al-Tamemi1, Bruce Mazer, David Mitchell
1Division of Allergy and Immunology, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.
Insights
DiGeorge anomaly can mimic severe combined immunodeficiency (SCID) presenting with infections but normal lymphocyte counts. Early suspicion is crucial for timely diagnosis and management of this 22q11.2 deletion syndrome variant.
Area of Science:
- Immunology
- Genetics
- Pediatrics
Background:
- DiGeorge (DG) anomaly, a form of 22q11.2 deletion syndrome, typically presents with cardiac, immune, and endocrine issues.
- Severe combined immunodeficiency (SCID) is characterized by profound defects in T, B, and NK cell function, leading to severe infections.
Observation:
- An atypical case of complete DG anomaly initially presented solely as SCID.
- The patient exhibited severe infections but had normal lymphocyte counts and immunoglobulin levels, delaying diagnosis.
- Key features of DG anomaly like hypocalcemia and velofacial/cardiac defects were absent at diagnosis.
Findings:
- This case highlights diagnostic challenges in SCID due to atypical presentations of DG anomaly.
- The 22q11.2 deletion syndrome demonstrates significant phenotypic variability.
- DG anomaly should be considered in the differential diagnosis of T- B+ NK+ SCID.
Implications:
- A high index of suspicion for primary immunodeficiency is needed in children with severe infections.
- Timely diagnosis of DG anomaly is critical as management strategies differ from other SCID forms.
- Recognizing varied presentations improves patient outcomes for 22q11.2 deletion syndrome.
Abstract:
We report an atypical case of complete DiGeorge (DG) anomaly that presented initially exclusively as severe combined immunodeficiency (SCID). The child had severe infections at diagnosis, in keeping with the SCID phenotype; however, normal lymphocyte counts and immunoglobulin levels were noted at admission, which delayed diagnosis. Importantly, the child presented without neonatal hypocalcemia or velofacial or cardiac abnormalities at the time of diagnosis, which masked underlying DG. This case outlines the difficulties in making the diagnosis of SCID in a timely manner and illustrates the variation in presentation of the 22q11.2 deletion syndrome. There should be a high index of suspicion for primary immunodeficiency among children with severe infections and, because management may vary, DG anomaly should be considered in the differential diagnosis of T- B+ natural killer+ SCID.
