Moraes C T, Ricci E, Petruzzella V, Shanske S, DiMauro S, Schon E A, Bonilla E
H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Disorders, New York, New York.
Nat Genet. 1992 Aug;1(5):359-67. doi: 10.1038/ng0892-359.
Large-scale deletions of mitochondrial DNA (mtDNA) are associated with a subgroup of mitochondrial encephalomyopathies. We studied seven patients with Kearns-Sayre syndrome or isolated ocular myopathy who harboured a sub-population of partially-deleted mitochondrial genomes in skeletal muscle. Variable cytochrome c oxidase (COX) deficiencies and reduction of mitochondrially-encoded polypeptides were found in affected muscle fibres, but while many COX-deficient fibres had increased levels of mutant mtDNA, they almost invariably had reduced levels of normal mtDNA. Our results suggest that a specific ratio between mutant and wild-type mitochondrial genomes is the most important determinant of a focal respiratory chain deficiency, even though absolute copy numbers may vary widely.
线粒体DNA（mtDNA）的大规模缺失与线粒体脑肌病的一个亚组相关。我们研究了7例患有卡恩斯-塞尔综合征或孤立性眼肌病的患者，这些患者的骨骼肌中存在部分缺失的线粒体基因组亚群。在受影响的肌纤维中发现了可变的细胞色素c氧化酶（COX）缺乏以及线粒体编码多肽的减少，但是虽然许多COX缺乏的纤维中突变型mtDNA水平升高，但它们几乎无一例外正常mtDNA水平降低。我们的结果表明，即使绝对拷贝数可能有很大差异，突变型和野生型线粒体基因组之间的特定比例是局灶性呼吸链缺陷的最重要决定因素。
