湖北汉族人群先天性巨结肠症内皮素受体B基因多态性与突变的研究

目的：研究中国湖北汉族人群内皮素受体-B(EDNRB)基因的多态性与散发性先天性巨结肠症发病的关系。 方法：收集104例散发性先天性巨结肠症患儿(病例组)及其中42例(子代组)的双亲(双亲组)血样， 120例正常儿童作对照(对照组)。 PCR-SSCP与DNA测序确定并比较EDNRB基因外显子4的突变与多态性位点(SNPs)等位基因与基因型分布差异，分析sHD表型与SNPs的关联，传递不平衡检验(TDT)分析3样本家系SNPs的传递不平衡。结果：EDNRB基因外显子4，检测到c831 G→A(L277L)多态性位点，未发现突变;病例组c831 G→A位点的等位基因A频率(68%∶53%)和纯合子AA基因型频率(49%∶30%)均明显高于对照组(P<0.01);病例组等位基因A频率明显高于双亲组(68%∶54%,P<0.01);短段型(SSA)患者等位基因A频率明显高于长段型(LSA)患者(76%∶63%,P<0.05);TDT检验未发现亲子代间在c831 G→A(L277L)位点存在传递不平衡。结论： 中国湖北汉族人群EDNRB多态性与散发性先天性巨结肠症发病关系密切，尤其与短段型表型 关系密切。

Polymorphisms and mutations of EDNRB gene in Hubei provincial patients of Han ethnicity with Hirschsprung disease

Abstract:Objective：To analyze the relationship between polymorphisms of EDNRB gene and Hubei provincial patients of Han ethnicity with sporadic Hirschsprung disease(sHD). Methods：Peripheral blood samples from 104 patients with sHD and 84 parents of 42 patients, and 120 normal children(as controls) were collected. PCR-SSCP and direct DNA sequencing were used to detect mutations and polymorphisms of exon-4 in EDNRB gene. The differences of allele frequencies and genotype distribution in polymorphic sites were further analyzed between the three groups. Allele frequencies of SNPs in forty-two sHD trios were analyzed by transmission disequilibrium test(TDT), and the association between phenotype of HD and SNPs was analyzed. Results：No mutant site was detected and one polymorphic site of c831 G→A(L277L) was observed in Hubei provincial patients of Han ethnicity with sHD. The allele frequency of A(68% vs 53%) and genotype frequency of AA(49% vs 30%) were significantly higher in sHD group than that in control group(P<0.01); the allele frequency of A in sHD group was significantly higher than that in parental group(68% vs 54%,P<0.01); The allele frequency of A in SSA group was significantly higher than that in LSA group(76% vs 63%,P<0.05). No transmission disequilibrium was detected in polymorphic site of c831 G→A(L277L) between parental generation and filial generation. Conclusions：The polymorphisms of EDNRB gene may play an important role in the pathogenesis of sporadic Hirschsprung disease, especially for patient with short-segment aganglionosis.