22q11.2 deletion syndrome and complex congenital heart defects *

ObjectiveTo investigate the frequency of 22q11 deletion syndrome (22q11DS) in patients with complex congenital heart disease.MethodsA prospective and consecutive cohort of patients with complex heart defects was evaluated in their first hospitalization at a cardiac intensive care unit of a pediatric hospital. For each patient, an assessment form was completed with demographic information and clinical evaluation. High resolution karyotyping and fluorescence in situ hybridization (FISH) to detect the presence of 22q11 microdeletion, were performed. Heart defects were classified by a cardiologist.ResultsThe sample cohort consisted of 66 patients. Karyotypic anomalies were observed in 5 patients (7.6%); however, none of them had 22q11 deletion. Evaluation by FISH was successfully done in 65 patients, identifying 22q11 microdeletion in two patients (3.1%). Out of the 66 patients with complex defects, 52 were carriers of conotruncal malformations and in 51 patients, analysis for 22q11 microdeletion by FISH was performed. The two patients with 22q11 microdeletion belonged to this group, representing a frequency of 3.9%. They had tetralogy of Fallot.Conclusion22q11DS is a frequent abnormality among patients with complex and conotruncal heart defects. Variations of the 22q11DS frequency among studies seem to be mainly associated with criteria used for patient selection and specific characteristics of the population analyzed.