Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA.
Neuromuscul Disord. 2010 Mar;20(3):204-6. doi: 10.1016/j.nmd.2010.01.006. Epub 2010 Feb 10.
We describe a 62-year-old woman with chronic progressive external ophthalmoplegia (CPEO), multiple lipomas, diabetes mellitus, and a novel mitochondrial DNA (mtDNA) mutation at nucleotide 4302 (4302A>G) of the tRNA(Ile) gene (MTTI). This is the first mutation at position 44 in the variable loop (V loop) of any mitochondrial tRNA. The muscle biopsy revealed 10% ragged-red/ragged-blue fibers and 25% cytochrome c oxidase (COX)-deficient fibers. No deletions or duplications were detected by Southern blot analysis. The 4302A>G transition was present only in the patient's muscle and single-fiber analysis revealed significantly higher levels of the mutation in COX-deficient than in normal fibers. Like tRNA(Leu(UUR)), tRNA(Ile) appears to be a "hot spot" for mtDNA mutations causing CPEO.
我们描述了一位 62 岁的女性，她患有慢性进行性眼外肌麻痹（CPEO）、多发性脂肪瘤、糖尿病以及位于 tRNA（Ile）基因核苷酸 4302（4302A>G）的新型线粒体 DNA（mtDNA）突变（MTTI）。这是线粒体 tRNA 任何位置 44 号的第一个突变。肌肉活检显示 10%的杂乱红/杂乱蓝纤维和 25%的细胞色素 c 氧化酶（COX）缺陷纤维。Southern 印迹分析未检测到缺失或重复。4302A>G 转换仅存在于患者的肌肉中，单纤维分析显示 COX 缺陷纤维中突变的水平明显高于正常纤维。与 tRNA（Leu（UUR））一样，tRNA（Ile）似乎是导致 CPEO 的 mtDNA 突变的“热点”。
