OBJECTIVETo investigate the clinical utility of multiplex ligation-dependent probe amplification (MLPA) for detecting 22q11 deletion and duplication in congenital heart disease (CHD) cases and to study the incidence of 22q11 deletion and duplicaton in different kinds of CHD.

METHODSForty eight probes of which 25 located in 22q11 low copy number region (LCR 22s A-H), 7 in 22q11 surrounding region (CES, 22q13) and 16 in chromosomes 4, 8, 10 and 17 were selected to detect 22q11 deletion and duplication in 181 preoperative children with CHD and 14 fetuses with serious CHD or CHD with multiple malformations. In these cases, karyotype analysis was also performed.

RESULTSMLPA demonstrated that 7 cases had 22q11 deletion [6 cases from CLTCL1 to LZTR1(LCR A-D) and 1 case from CLTCL1 to PCQAP (LCR A-C)] and that 1 case had 22q11 duplication,spanning from ZNF74 to LZTR1(LCR B-D). The phenotypes of heart defect included ventricular septal defect, atrioventricular septal defect, pulmonary stenosis and tetralogy of Fallot. Karyotype analysis showed that 1 case had 21q deletion [46, XY, 21q], 1 case had mosaic trisomy 8 [47,XY, +8/46, XY(1:2)] and 4 cases had trisomy 21. One of the 4 cases with trisomy 21 had concurrent 22q11 duplication.

CONCLUSIONSMLPA is a rapid, sensitive, site specific and relatively inexpensive method for diagnosis of 22q11 deletion and duplication in CHD. 22q11 deletion and duplication may cause various kinds of CHD, suggesting that genetic detection should be performed routinely in CHD patients.