title: Variation in prevalence of chromosome 22q11 deletion in subtypes of conotruncal defect in 254 children.
abstract: OBJECTIVE
  To determine the frequency of chromosomal aberrations particularly 22q11 deletion in Indian children ≤2 years with different types of conotruncal malformations and their association with abnormal aortic arch. Additionally, extracardiac features were also studied.
  
  
  METHODS
  Conventional cytogenetic and fluorescence in situ hybridization analyses were performed in 254 patients with conotruncal defects. Multivariable logistic regression analysis was performed to ascertain extracardiac features helpful in identifying high-risk patients with deletion.
  
  
  RESULTS
  Chromosomal abnormalities were identified in 52 (21%) children, of whom 49 (94%) showed 22q11 deletion and 3 (6%) had abnormalities of chromosome 6, 2 and X. None of the 11/254 children with tetralogy of Fallot with absent pulmonary valve showed deletion. The association of 22q11 deletion with right sidedness of the aortic arch varied with the type of conotruncal defect. The eight extracardiac features in combination showed 93.5% agreement with the presence of deletion.
  
  
  CONCLUSIONS
  The extracardiac features along with specific type of conotruncal defect and associated cardiovascular anomaly should alert the clinician for 22q11 deletion testing. However, if deletion analysis is not possible, specific extracardiac features (six dysmorphic facial features, thin long fingers and hypocalcemia) can help to identify an increased risk of 22q11 deletion in patients with conotruncal defect.
authors.affiliation: Department of Human Cytogenetics, Amrita Institute of Medical Sciences and Research Centre, Kochi, India. alkaanilkumar@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Anilkumar
authors.forename: M
authors.initials: M
authors.lastname: Kappanayil
authors.forename: M V
authors.initials: MV
authors.lastname: Thampi
authors.forename: S
authors.initials: S
authors.lastname: Nampoothiri
authors.forename: K R
authors.initials: KR
authors.lastname: Sundaram
authors.forename: D M
authors.initials: DM
authors.lastname: Vasudevan
mesh_terms: D058165:22q11 Deletion Syndrome / Q000453:epidemiology / Q000235:genetics*; D016009:Chi-Square Distribution; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D016001:Confidence Intervals; D003582:Cytogenetics; D003906:Developing Countries; D005260:Female; D017353:Gene Deletion; D014644:Genetic Variation / Q000235:genetics*; D006330:Heart Defects, Congenital / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods