Study Of RET Proto-oncogene Exon 13 DNA Polymorphism In Patients With Hirschsprung's Disease In Tianjin District

Objective:Hirschsprung's disease(HSCR) is a common congenital disease of digestive tract,characterized by the absence of intestinal ganglion cells.It is shown that RET gene is mainly susceptible in many genes which are correlate with HSCR. RET proto-oncogen polymorphisms and haplotypes,containing disease associated mutations,are believed to be genetic modifiers and might be associated with an increased relative risk for the development of disorders derived from neural crest cells. Because polymorphisms are comparatively common in the population,they could bestow a much higher attributable risk on the general population as compared with rare mutations in high-penetrance disease susceptibility genes such as RET proto-oncogen.The aim of this study is analyzed single nucleotide polymorphisms in the RET proto-oncogen exon 13 and their correlations with the etiopathogenisis of HSCR.Materials and Methods:73 blood samples were exacted from the patients who were diagnosed and treated in Tianjin Children's Hospital between May.2003 and Aug.2007.The patients aged from 24 days to 7 years(59 men,14 women,13 L-HSCR,60 S-HSCR),who were all sporadic and nor HSCR hereditary history.All patients were confirmed HSCR by pathological diagnose.10 control blood samples was exacted from the patients who weren't related with HSCR.Genomic DNA was extracted from whole blood samples by salt fractionation.Polymerase Chain Reaction (polymerase chain reaction,PCR) amplified in the 13 exon of the RET proto-oncogene.Single-nucleotide polymorphisms were analyzed by direct DNA sequencing.Then,we detect the difference between the allele in two groups.Results:SNP(single nucleotide polymorphism) in T769G site was found.The frequency of allele G was higher than allele T.The allele frequencies of T769G were G89.0%,T11.0%in HSCR group,and G50.0%,T50.0%in control group.There was significant statistic difference in allele frequency(χ~2=17.449,P＜0.001).Molecular results were compared between two clinical genotypes.There was no significant statistic difference in two allele frequency.Conclusions:The results confirm that the T769G polymorphism in the RET proto-oncogene Exon 13 play a role in the aetiology to the occurrence of HSCR.And there are ethnic differences in this gene locus.The frequency of allele isn't related with HSCR phenotype.