Association of 22q11 deletion with isolated congenital heart disease in three Chinese ethnic groups

Background Congenital heart disease (CHD) is the most common type of heart disease among children. About 75% of DiGeorge syndrome (DGS) and velo-cardio-facial syndrome (VCFS) includes CHD. A deletion within chromosome 22q11.2 has been identified in the majority of patients with DGS and VCFS. And 22q11.2 deletion has become one of the markers used to study CHD in these syndromes. Whether 22q11.2 deletion is associated with isolated CHD is not known and was the topic of this study. Methods and results We studied the 22q11.2 deletion in three Chinese ethnic groups (Tai, Bai and Han people) with 19 sporadic, isolated CHD by genotype and haplotype analysis with D22S420 etc. 11 consecutive polymorphic microsatellite markers. Among 19 isolated CHD patients, four had Tetralogy of Fallot (TOF), five exhibited Ventricular Septal Defect (VSD), five showed Atrial Septal Defect (ASD) and 5 had Patent Ductus Arteriosus (PDA). In some isolated CHD patients, 3 Mb and 1.5 Mb deletion to chromosome 22q11.2 was found. 2 of 4 TOF (50%) and 1 of 5 VSD (20%) and 1 of 5 PDA (20%) respectively were found to have deletions at D22S944. Conclusions 22q11.2 deletion can be detected in isolated TOF, VSD and PDA of three Chinese ethnic groups, without detectable 22q11.2 deletion in those isolated ASD patients examined thus far. Our finding may be the first to show the 22q11.2 deletion in sporadic, isolated PDA/VSD patients whose family members are without CHD. In addition, D22S420 etc. 11 consecutive polymorphic microsatellite markers are very useful for the determination of 22q11.2 deletion in isolated CHD in China.