先天性巨结肠症SIP1基因外显子3和外显子4的突变分析

目的 探讨SIP1基因外显子3和外显子4与散发性先天性巨结肠(Hirschsprung disease,HD)的关联性.方法 检测150例HD患儿SIP1基因突变.采用PCR-变性梯度凝胶电泳(PCR-degenerating gel gradient electrophoresis,PCR-DGGE)与DNA测序法检测患儿SIP1基因exon3 and exon4的突变.另选取150例正常人(排除家族性顽同便秘及其他先天性消化道畸形史健康儿童)外周血DNA作为对照组.结果 在HD组exon3 PCR-DGGE发现83例异常电泳条带,测序证实67/83例SIP1发生在突变集中区域,为错义突变(ACC→ATC,苏氨酸→异亮氨酸).在HD组exon4发现101例异常电泳条带,测序证实68/101例SIP1发生在突变集中区域,有4种突变(CAC→TAC,组氨酸→酪氨酸;GAG→GAT,谷氨酸→天门冬氨酸;GCC→GTC,丙氨酸→缬氨酸;TGT→TTT,胱氨酸→苯丙氨酸).DGGE检测正常对照组中未发现异常电泳条带,测序未发现突变.结论 SIP1基因为HD的致病基因,突变类型多样,已发现热点突变;提示SIP1基因与HD发病存在一定程度的关联.

Mutations in exon3 and exon4 of SIP1 gene in children with isolated Hirschsprung's disease

Objective To screen the mutations of SIP1 gene in children with isolated Hirschsprung disease (HD).Methods Polymerase chain reaction (PCR)and degenerating gel gradient electrophoresis (DGGE)was employed to amplify and separate the target gene.The mutations in exon3 and exon4 of SIP1 gene of 150 HD patients were explored by direct nucleotide sequencing analysis.The peripheral blood of 150 health individuals who had no congenital gastrointestinal malformations and family history of constipation were taken as normal controls.Results Eighty three abnormal electrophoresis bands of exon3 PCR products were found in HD patients.DNA sequencing showed that mutations were found in 67 of the 83 abnormal bands,which was (ACC→ATC).One hundred and one abnormal electrophoresis bands of exon4 PCR products were found in HD patients.Mutations in exon4 of SIP1gene,which were (CAC→TAC;GAG→GAT;GCC→GTC;TGT→TTT),were found in 68 abnormal bands.No abnormal electrophoresis bands of normal controls' PCR products were found.Conclusions Mutations of the SIP1 gene are associated with the pathogenesis of HD.