title: DiGeorge anomaly in the absence of chromosome 22q11.2 deletion.
abstract: 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.
authors: Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA. alan.rope@hsc.utah.edu
authors: Alan F
authors: AF
authors: Rope
authors: Deborah L
authors: DL
authors: Cragun
authors: Howard M
authors: HM
authors: Saal
authors: Robert J
authors: RJ
authors: Hopkin
mesh_terms: 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