EDNRB基因编码区点突变及多态性在浙江地区散发性先天性巨结肠症中的检测与分析

本实验应用聚合酶链反应-单链构象多态性(single strand confbrmation polymorphism analysis of polymerase chain reaction products,PCR-SSCP)和DNA直接测序技术,对75例浙江地区散发性先天性巨结肠病例EDNRB基因编码区的全部7个外显子,进行了点突变与单核苷酸多态性的检测与分析,探讨浙江地区先天性巨结肠患者EDNRB基因的突变特征,阐明EDNRB基因与散发性先天性巨结肠症发病之间可能存在的关系。结果有6例患者在第4外显子上检测到密码子277位点 CTG→CTA的置换,导致亮氨酸的同义突变(L277L),属于单核苷酸多态性,发生率为8％(6/75)。有 2例患者在第2外显子上检测到密码子185位点GTG→ATG的置换,导致缬氨酸到蛋氨酸的错义突变(V185M),此突变型未在国内外文献中报道过,认为是新的基因突变型,突变率2．7％(2/75)。研究结果表明,浙江地区先天性巨结肠群体可发生EDNRB基因的杂合性突变,提示EDNRB基因与先天性巨结肠症的发病存在一定程度的关联。

CODING-SEQUENCE MUTATION AND POLYMORPHISM ANALYSIS OF EDNRB GENE IN PATIENTS WITH HIRSCHSPRUNG'S DISEASE FROM ZHEJIANG REGION

To determine the characters of EDNRB gene in patients with sporadic Hirschsprung's disease (HD) and discuss the relationship between mutation of EDNRB gene and HD, seventy five sporadic HD cases and forty normal cases as control were collected and DNA was extracted from peripheral white blood cells by standard method. All seven exons of EDNRB gene were analyzed by single strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP) and direct sequencing. In result, A G --> A transition in codon 277 was observed in exon 4 in six patients. This variation leads to a nonsense mutation (L277L) and is a previously described polymorphism, the rate of variation is 8% (6/75). A G --> A transition in codon185 was detected in exon 2 in two patients, this is a novel heterozygous mutation, leading to a missense mutation (V185M), and the rate of mutation is 2.7% (2/75). So we can conclude that mutation of EDNRB gene can be detected in Chinese patients with sporadic HD and EDNRB gene might play an important role in the pathogenesis of HD.