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目的探讨中国人遗传性非息肉病性结直肠癌(HNPCC)患者hMLH1与hMSH2基因的种系突变特点。方法对诊治的6个HNPCC家系的先证者用聚合酶链反应(PCR)的方法扩增其hMLH1及hMSH2的35个外显子,SSCP方法检测其变异,对可疑突变者进行自动测序以确定突变类型。结果6例先证者SSCP检测在3例患者中发现4处异常条带,自动测序证实hMSH211外显子有1处插入突变和1处错义突变、13外显子有1处错义突变,1例在hMLH118外显子及hMSH215外显子均有插入突变。结论中国人HNPCC的错配修复基因突变以hMSH2为主,插入造成的移码突变和错义突变仍为主要病理突变类型。
Objective To investigate the germline mutation characteristics of hMLH1 and hMSH2 genes in Chinese patients with hereditary nonpolyposis colorectal cancer (HNPCC). Methods The probands of six HNPCC pedigrees diagnosed and treated by polymerase chain reaction (PCR) were used to amplify 35 exons of hMLH1 and hMSH2. The SSCP method was used to detect the variation and the suspicious mutants were sequenced automatically to determine Mutation type. Results Six cases of proband SSCP detected four abnormal bands in three patients. Sequencing of hMSH211 exon revealed one insertion mutation and one missense mutation in exon 1, a missense mutation in exon 13, One case had hMLH118 exon and hMSH215 exon insertion mutation. Conclusion The mutation of mismatch repair gene in Chinese HNPCC is mainly hMSH2, and the frameshift mutation and missense mutation caused by insertion are still the main pathological mutation types.