Holme E, Tulinius M H, Larsson N G, Oldfors A
Department of Clinical Chemistry, Gothenburg University, Sahlgren's Hospital, Sweden.
Biochim Biophys Acta. 1995 May 24;1271(1):249-52. doi: 10.1016/0925-4439(95)00035-3.
An important feature of the mitochondrial genom is the occurrence of heteroplasmy and the possibility for transmission to the offspring of various proportions of wild-type and mutated mtDNA. We have investigated the proportion of the tRNALys A8344G mutation, the tRNALeu(UUR) A3243G mutation, and the ATPase 6 T8993G mutation in patients with MERRF, MELAS, and Leigh's syndrome and their maternal relatives. The level of mutated mtDNA in the offspring of carriers of the tRNALys mutation is correlated to the level in lymphocytes in the mother and seems to be transmitted by an essentially random mechanism where only a few mtDNA copies are founders of the mitochondrial genom in the offspring and the probability that the mutation is not transmitted to the offspring is high when the mothers carriers predominantly wild-type mtDNA. However, we found age-related differences in the distribution of mutated mtDNA in carriers of the tRNALys and tRNALeu mutations, which have to be considered before levels of mutated mtDNA are used for prediction of prognosis and transmission of a disorder.
线粒体基因组的一个重要特征是异质性的存在以及野生型和突变型线粒体DNA以不同比例传递给后代的可能性。我们研究了患有肌阵挛性癫痫伴破碎红纤维综合征（MERRF）、线粒体脑肌病伴乳酸血症和卒中样发作（MELAS）以及 Leigh 综合征患者及其母系亲属中赖氨酸转运RNA（tRNALys）A8344G 突变、亮氨酸转运RNA（tRNALeu(UUR)）A3243G 突变和 ATP 酶 6 T8993G 突变的比例。tRNALys 突变携带者后代中突变型线粒体DNA 的水平与母亲淋巴细胞中的水平相关，并且似乎通过一种基本随机的机制传递，即只有少数线粒体DNA 拷贝是后代线粒体基因组的奠基者，当母亲主要携带野生型线粒体DNA 时，突变不传递给后代的概率很高。然而，我们发现 tRNALys 和 tRNALeu 突变携带者中突变型线粒体DNA 的分布存在与年龄相关的差异，在将突变型线粒体DNA 水平用于预测疾病的预后和传递之前，必须考虑这些差异。
