The Genetic Study Of Tetralogy Of Fallot

Section 1 Screening and Identification of Genes Associated with Human Tetralogy of FallotObjective: To investigated the the molecular mechanism of the development of human Tetralogy of Fallot (TOF). Methods: To investigate the developmental mechanism of human TOF, we compared gene expression profiles of the right ventricular outflow tract myocardium tissues of TOF patients and normally developed fetuses by the DNA microarray technique. With the aid of bioinformatics, we classified the differentially expressed genes and picked out genes which may contribute to the occurrence of TOF. Then the TOF related genes were verified by quantitative real-time PCR and immunohistochemistry in more samples to neutralize the impacts brought by the mismatch of ages and surgical manipulations. Results: Totally, 242 genes were commonly differentially expressed in all the microarray cases. These genes were divided into 13 categories based on the biological process in which they were involved. In the category of developmental related genes, we found the expression level of two conotruncal defect candidate genes CSPG2 and NTRK3 were down-regulated in TOF patients. Ensuring verification procedures confirmed that the expression level of NTRK3 was specifically decreased in TOF patients at both mRNA and protein level, while the expression level of CSPG2 decreased with the increase of age. Conclusions: Our results, in combined with several other previous reports about NTRK3 in animal models, suggested that the insufficient expression of NTRK3 may contribute to the formation of the right ventricular outflow tract defect of human TOF. Section 2 Mutation Screening of HEY2 Gene in Chinese patients with Tetralogy of FallotObjective: To screen the mutation of HEY2 gene in Chinese patients with sporadic tetralogy of Fallot (TOF) .Methods :52 patients with tetralogy of Fallot were selected from Fuwai hospital, After extracting the genomic DNA, the HEY 2 gene was amplified by the means of "touch down polymerase chain reaction"(touch down PCR). After being purified, the PCR products of HEY2 were conducted to the sequencing reaction to investigate whether there were mutations or SNPs or not .Results: No pathogenic mutation was identified in all TOF patients. Only 2 single nucleotide changes including C.222T—G in exon 3 and C.621A—T in exon 5 were found, however both of these 2 heterozygous changes do not alternate the amino acid of the HEY2 protein . Conclusions :The mutation of HEY2 gene might not be associated with tetralogy of Fallot in Chinese population.