22Q11.2 DELETIONS IN A SERIES OF PATIENTS WITH NONSELECTIVE CONGENITAL HEART-DEFECTS - INCIDENCE, TYPE OF DEFECTS AND PARENTAL ORIGIN

Previous studies have indicated a wide spectrum of incidences of 22q11 .2 deletions in isolated and syndromic (sporadic or familial) cases of conotruncal heart defects, whereby the detection rate of the deletion varied from 65% in one study to 0 in another. We analysed 110 patient s with non-selective syndromic or isolated non-familial congenital hea rt malformations by fluorescence in situ hybridization (FISH) using th e D22S75 DiGeorge chromosome (DGS) region probe. A 22q11.2 microdeleti on has been detected in 9/51 (17.6%) syndromic patients. Five were of maternal origin and four of paternal origin. None of the 59 patients w ith isolated congenital cardiac defect had a 22q11.2 deletion. We comp ared the cardiac anomalies of our patients with a 22q11.2 deletion wit h those of previously published series and we describe types of congen ital heart defects which appear to be often associated with a 22q11.2 deletion. The ability to detect such types of heart defects and to pro vide an early diagnosis of 22q11.2 deletion is particularly relevant i n very young infants, who often show only very mild expression of the otherwise well-characterized phenotypes of the DiGeorge/velo-cardio-fa cial syndrome (DG/VCFS).