title: Frequency of 22q11.2 microdeletion in sporadic non-syndromic tetralogy of Fallot cases.
abstract: BACKGROUND
  Tetralogy of Fallot (TOF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velocardiofacial (VCFS) syndromes. The deletion of chromosome 22q11 has also been demonstrated in sporadic or familial cases of TOF. The aim of the present study was to investigate the frequency of del22q11 in patients with non-syndromic TOF seen at a tertiary Pediatric Cardiology care center.
  
  
  METHODS
  One hundred and twenty three non-syndromic TOF patients were selected and evaluated by history, physical examination and review of medical records. Venous blood was drawn for genomic DNA extraction after informed consent 22q11 microdeletion diagnosis was conducted through a standardized SNP genotyping assay and consecutive homozygosity mapping. Phenotype-genotype correlations regarding cardiac anatomy were conducted.
  
  
  RESULTS
  We evaluated 123 non-syndromic TOF patients for a 22q11 deletion. 105 (85.4%) patients presented pulmonary stenosis and 18 (14.6%) had pulmonary atresia. Eight patients (6.5%) were found to have a deletion. Of the deleted patients, three (37.5%) presented pulmonary atresia. We have verified a tendency towards a higher prevalence of pulmonary atresia when comparing TOF patients with and without 22q11 microdeletion.
  
  
  CONCLUSIONS
  22q11.2 deletion in non-syndromic TOF patients is present in approximately 6% of patients. We suggest a tendency towards a higher prevalence of pulmonary atresia in non-syndromic TOF patients with 22q11 microdeletion. Molecular genetic screening of non-syndromic TOF patient may be important for the correct care of these patients and a more specific genetic diagnostic and counseling.
authors.affiliation: Laboratory of Genetics and Molecular Cardiology and Pediatric Cardiology Division, Heart Institute (InCor), Sao Paulo University Medical School, Sao Paulo, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Gioli-Pereira
authors.forename: A C
authors.initials: AC
authors.lastname: Pereira
authors.forename: D
authors.initials: D
authors.lastname: Bergara
authors.forename: S
authors.initials: S
authors.lastname: Mesquita
authors.forename: A A
authors.initials: AA
authors.lastname: Lopes
authors.forename: J E
authors.initials: JE
authors.lastname: Krieger
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005838:Genotype; D006801:Humans; D015994:Incidence; D008297:Male; D011336:Probability; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018570:Risk Assessment; D012720:Severity of Illness Index; D013771:Tetralogy of Fallot / Q000453:epidemiology / Q000235:genetics*