DiGeorge anomaly in the absence of chromosome 22q11.2 deletion.
OBJECTIVE
To test the hypothesis that the prevalence of deletion 22q11.2 among individuals who meet criteria for DiGeorge anomaly (DGA) is lower than the 90% commonly cited.


METHODS
Participants were identified through retrospective chart reviews on all patients who underwent testing for deletion 22q11.2 and all patients with a diagnosis of "DiGeorge" or any of the major criteria associated with DGA at a large pediatric hospital over a period of 6 years. DGA was confirmed in 64 individuals, based on the presence of at least 2 of the following features: (1) cellular immune deficiency and/or absence of part or all of the thymus; (2) hypocalcemia and/or parathyroid deficiency; (3) congenital heart disease.


RESULTS
Of the 64 individuals with DGA, 29 (45%) did not have a chromosome 22q11.2 deletion. Among this deletion-negative subset, diabetic embryopathy and other chromosome abnormalities were the most commonly recognized underlying etiologies.


CONCLUSIONS
These findings challenge a widely held belief that nearly 90% of DGA is due to chromosome 22q11.2 deletion. This study also calls attention to the heterogeneity of DGA, highlights similarities and differences between those with and without a chromosome 22q11.2 deletion, and attempts to resolve some confusing features of conditions associated with DGA.
Rope
Alan F
AF
Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA. alan.rope@hsc.utah.edu
Cragun
Deborah L
DL
Saal
Howard M
HM
Hopkin
Robert J
RJ
D002872:Chromosome Deletion; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D015331:Cohort Studies; D004062:DiGeorge Syndrome / Q000175:diagnosis* / Q000209:etiology* / Q000378:metabolism; D005820:Genetic Testing; D006330:Heart Defects, Congenital / Q000150:complications; D006801:Humans; D006996:Hypocalcemia / Q000150:complications; D007111:Immunity, Cellular / Q000502:physiology; D012189:Retrospective Studies