97例线粒体肌病/脑肌病患者的线粒体DNA突变分析

目的 探讨我国不同临床类型的线粒体脑肌病的线粒体DNA(mtDNA)突变特点以及基因型和表型之间的相关性.方法 对经临床和病理诊断为线粒体肌病/线粒体脑肌病的97例患者,提取其肌肉和/(或)白细胞mtDNA,用Southern杂交检测mtDNA的大片段缺失、以聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术检测常见类型的点突变(包括A3243G、A8344G、T8993G、　T8993C、T3271C突变)、并对部分患者进行mtDNA伞长测序寻找有无其他的突变位点.结果 97例患者中有81例患者存在mtDNA突变,突变类型包括单一的大片段缺失21例,多发的大片段缺失4例,A3243G突变43例,A8344G突变6例,T8993G、T8993C、T3271C突变各1例.KSS/CPEO与单发的mtDNA大片段缺失相关、MELAS与A3243G点突变、MERRF与A8344G点突变、母系遗传的Leigh　病与8993位点的突变相关.另外在4例线粒体肌病患者中发现细胞色素b编码基因A15316G　(T194A)、G15221A(D159N),ATPase6编码基因G9196A(D224N)和16SrRNA C2835T突变各1例.结论 国人不同类型线粒体肭肌病的mtDNA突变类型与国外外的报道道基本一致.虽然线粒体脑肌病的临床表刑和基因型之间有一定的相关件,但不同的基因型和临床表型之间也存在一定的交叉,反映了线粒体病的异质性特点.

Mitochondrial DNA mutation analysis in 97 Chinese patients with mitochondrial cephalomyopathy

objetqive To investigate the characteristics of mitochondrial DNA mutations and genotype-phenotype correlations in mitochondrial encephalomyopathies.Methods Biopsy of skeletal muscle and collection of peripheraI blood samples were conducted among 97 patients with mitochondrial encephalomyopathies.Southern blotting,PCR-RFLP and direct sequencing of PCR products were performed to search large scale deletions.and common and uncommon pathological point mutations in the muscle and/ or blood mtDNA.Results Seventy-seven patients were identified to be with mitochondrial DNA mutations. including single large deletion(n=21),multiple large-scale deletions(n=4),A3243G point mutation (n=43),A8344G point mutation(n=6),T8993G mutation(n=1),T8993C mutation(n=1),and 1r3271C mutation(n=1).Total mtDNA sequencing revealed 4 difierent noveI point mutations in four unrelated patients with isolated mitochondrial myopathy.Conclusion The type and frequency of mtDNA mutations in this series of Chinese mitochondrial encephalopathies are consistent with those reported abroad, Ahhough there is some association between the genotype and phenotype,heterogeneity in phenotype and genotype iS also a prominent feature seen in this series of patients.especially those with A3243G mutation.