Study On The Relationship Between 22q11 Microdeletion And Simple Congenital Heart Disease

Objective: The purpose of this study was to determine the frequency of 22q11 microdeletions in pediatric patients with simple congenital heart disease, the parental origin of the deleted chromosome, and relation of genotype to phenotypes.Methods: Study was conducted on 22 children with simple congenital heart disease, and their unaffected parents (n=44, as control group),using PCR with 6 polymorphic short tandem repeats(STR)markers: 102STS,D22S257,D22S3,D22S306,D22S420,D22S427 in chromosome 22q11 region. PCR was used to analyze the 6 STR markers. The amplified fragments were subjected to electrophoresis in un-dematured PAGE gel. To define the deletion at the individual patient level, we conducted detailed haplotype analysis on 22 patients and their parents.Results: Chromosome 22q11 microdeletion was detected in 4/22 patients with congenital heart disease, the frenquency of 22q11 deletion in patients VSD,TOF and PS was 16.7% in VSD, 25% in TOF,50% in PS. There was no 22q11 deletion detected in patients with ASD and PDA. Paternal and maternal origins of de122q11 were identified in 1 and 3 patients respectively. Compared with predicted value, the frequencise of heterozygosity for marker D22S303,D22S306 and D22S427 were significantly lower in patients with CHD (p<0.01). Conclusion: 1. The results indicated that microdeletion of 22q11 is an important genetic etiology in patients with some category of congenital heart disease.2. There existed LOH on D22S306 in pediatric patients with congenital heart disease.3. Compared with predicted value, the frequencise of heterozygosity for marker D22S303,D22S306 and D22S427 were significantly lower in patients with simple CHD.4. PCR is a rapid, simply and effective method to analyze the deleted chromosome.