中国人先天性巨结肠RET基因突变家系研究

Mutations of RET proto-oncogene in Chinese familial Hirschsprung's disease

目的 研究中国人先天性巨结肠(HD)与RET基因突变之间的关系。方法 采用聚合酶链反应-单链构象多态性分析(PCR-SSCP)技术及DNA测序,对RET基因第13外显子突变阳性HD患儿的家系作研究,并对另38例散发性HD和30例健康无便秘史儿童进行突变筛查。结果 在家系1中,3例患儿均发现在RET基因碱基18974位插入G,导致框架移位突变。在家系2中,先证者在碱基18888位发生T→G的杂和性替代,导致Leu745Leu同义突变,其父亲为该致病突变的携带者,母亲正常。另38例散发性HD中,2例为突变阳性。结论 中国人HD的发生与RET基因突变有密切关系,该基因突变是家族性HD重要的分子遗传学基础。

Objective To search for the mutations of RET proto-oncogene in Chinese patients with Hirschsprung's disease (HD). Methods Genomic DNA was extracted from the venous blood of probands and their relatives in two genealogies. Exon 13 of RET proto-oncogene was analyzed with polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). The positive amplifying products were se- quenced. Thirty-eight sporadic HD patients and 30 normal children were screened for mutations of exon 13 of RET proto-oncogene simultaneously. Results Three cases with HD in one family were found to have a G heterozgous insertion at nucleotide 18974 of RET cDNA(18974 ins G), which resulted in a frameshift mu- tation. In another family, a heterozygosity for a T to G transition at nucleotide 18888 which resulted in a synonymous mutation of Leu to Leu at codon 745, was detected in the proband and his father. Two causative RET mutations were confirmed in 2 cases of 38 sporadic HD patients: Lys to Glu substitution at codon 756 and a 18974 ins G. Conclusion The mutation of RET proto-oncogene may play an important role in the pathogenesis of HD in Chinese.