FREQUENCY OF 22Q11 DELETIONS IN PATIENTS WITH CONOTRUNCAL DEFECTS

Objectives. This study was designed to determine the frequency of 22q1 1 deletions in a large, prospectively ascertained sample of patients w ith conotruncal defects and to evaluate the deletion frequency when ad ditional cardiac findings are also considered. Background. Chromosome 22q11 deletions are present in the majority of patients with DiGeorge, velocardiofacial and conotruncal anomaly face syndromes in which cono truncal defects are a cardinal feature. Previous studies suggest that a substantial number of patients with congenital heart disease have a 22q11 deletion. Methods. Two hundred fifty-one patients with conotrunc al defects were prospectively enrolled into the study and screened for the presence of a 22q11 deletion. Results. Deletions were found in 50 .0% with interrupted aortic arch (IAA), 34.5% of patients with truncus arteriosus (TA), and 15.9% with tetralogy of Fallot (TOF). Two of 6 p atients with a posterior malalignment type ventricular septal defect ( PMVSD) and only 1 of 20 patients with double outlet right ventricle we re found to have a 22q11 deletion. None of the 45 patients with transp osition of the great arteries had a deletion. The frequency of 22q11 d eletions was higher in patients with anomalies of the pulmonary arteri es, aortic arch or its major branches as compared to patients with a n ormal left aortic arch regardless of intracardiac anatomy. Conclusions . A substantial proportion of patients with IAA, TA, TOF and PMVSD hav e a deletion of chromosome 22q11. Deletions are more common in patient s with aortic arch or vessel anomalies. These results begin to define guidelines for deletion screening of patients with conotruncal defects .