The Study On The Relationship Among NKX2-5 Mutations And ASD,VSD

Background Ventricular Septal Defect（VSD） is a commom congenital heart disease covering about 20% of the total CHDs while Atrial Septal Defect（ASD） is just behind VSD with a rate of 6-10%. It will cause pulmonary hypertension, enlarged atrium or ventricle, failure of the heart, Eisenmenger’s Syndrome, arrhythmia or even sudden death if persistent blood flows across the septal defect. It is a serious economical load for both families and the society. NKX2-5 is one of the earliest transcription factors expressed in the early stage of heart development whose mutations may lead to CHD and atrioventricular block. In this study, we screened the mutations and SNPs of the gene in CHD children to provide theoretical basis for the relationship among NKX2-5 mutations and ASD, VSD.Methods A computional predicted isoform was found except three identified isoforms according to NKX2-5 sequence in Genbank. Identifying whether it was expressed in heart, we extracted RNA and RT-PCR of two discarded diseased heart tissues from two patients suffering from CHD. Meanwhile, use DNA-PCR and direct sequencing technology to detect sequences of NKX2-5 in 50 cases of VSD, 51 cases of ASD and 50 control children. Observe the mutations by contrast to the controls.Results1. Predicted isoform was detected in neither patient.2. A rare SNP（c.104G>T, rs376790353） was found in a simple ASD patient and was found nobody else.3. Three common SNPs（c.63 G > C,rs2277923; c.606 A > G, rs3729753 and c.195G>C,rs3131915） were found in all and there was no difference of gene distribution and allele frequency among the three groups with a P>0.05.4. A synonymous mutation（c.460C>G, p.Ser264 Ser） in exon 2（NM₀04387.3） was found in another ASD patient.Conclusion1. Predicted isoform may not exist in patients’ myocardium in this study.2. SNP rs376790353 might be associated with ASD whereas rs2277923, rs3729753 and rs3131915 were not.