中国人先天性巨结肠RET基因突变特征研究

THE MUTATION CHARACTER OF THE RET PROTO-ONCOGENE IN CHINESE PATIENTS WITH HIRSCHSPRUNG' S DISEASE

为了研究中国人先天性巨结肠(HD)RET基因突变特征,从分子水平探讨先天性巨结肠症(HD)的发病机理,揭示中国人群HD与RET基因突变的关系。我们应用聚合酶链反应-单链构象多态性(PCR-SSCP)-DNA测序方法,对50例HD患儿和30例无便秘正常对照者,进行RET基因第13外显子突变筛查,并对第13外显子突变阳性患儿家系作研究。结果发现在50例HD患儿中,有7例第13外显子扩增片段在SSCP分析时出现泳动变位。经DNA测序证实,有3种点突变类型(错义、同义和移码),第13外显子突变率为14%(7/50)。在7例第13外显子突变的患儿中,发现2例患儿的父亲存在与其子相同的突变。实验表明中国先天性巨结肠人群存在着RET基因突变,且以杂和性点突变为主,HD具有一定的遗传性。

To clarify the pathogenesis of Hirschsprung's disease (HD) on molecular level and to reveal the relationship between the RET proto-oncogene and Chinese patients with HD, the mutations of the RET proto-oncogene were studied in 50 Chinese patients with HD and 30 normal children with an-obstipation as control. Genomic DNA was extracted from venous blood of the HD patients and the normal children. Polymerase chain reaction (PCR) products, which were amplified using specific primers (RET; exon13), were electrophoresised to analyze the single-strand conformational polymorphism (SSCP) patterns. DNA sequences of exon 13 of the RET proto-oncogene were determined in patients showing abnormal SSCP bands. And then the familial tracking research was done for the patients with Exon 13 mutation. In 50 HD patients, seven cases were found with apparently abnormal SSCP bands. And three point mutations were proved by DNA sequencing. In the parents of seven HD patients with Exon 13 mutation, two patients' fathers had the same mutation as their children. The results suggest that the mutation of the RET proto-oncogene may have a high freqency in Chinese patients with HD, especially the heterozygous point mutation. And HD has the heredity tendency.