Deschauer Marcus, Swalwell Helen, Strauss Maria, Zierz Stephan, Taylor Robert W
Department of Neurology, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany.
Arch Neurol. 2006 Jun;63(6):902-5. doi: 10.1001/archneur.63.6.902.
An extensive range of molecular defects have been identified in the human mitochondrial genome (mitochondrial DNA); many are associated with well-characterized, progressive neurological syndromes, but a minority of patients have uncharacteristic phenotypes in which symptoms may be relatively mild.
To describe a novel transfer RNA(Phe) mutation of mitochondrial DNA in a late-onset case with a mild phenotype of mitochondrial disease.
Case report.
A 66-year-old woman presented with a 4-year history of walking difficulties due to exercise intolerance and paresthesia in the feet. Clinical examination results were normal. Her deceased mother had similar walking difficulties, but her sister and 2 children were unaffected.
The demonstration of a marked histochemical defect in cytochrome c oxidase activity on muscle biopsy prompted molecular investigation of mitochondrial DNA, revealing a novel maternally inherited mutation in the variable loop of the mitochondrial transfer RNA(Phe) gene. This 622G>A transition was heteroplasmic and segregated with cytochrome c oxidase deficiency in single fibers.
This case serves to illustrate that primary defects of the mitochondrial genome should be considered even in older patients with late-onset, mild neuromuscular symptoms.
人类线粒体基因组（线粒体DNA）中已发现广泛的分子缺陷；许多与特征明确的进行性神经综合征相关，但少数患者具有非典型表型，其症状可能相对较轻。
描述1例线粒体疾病轻度表型的迟发性病例中的一种新的线粒体DNA苯丙氨酸转运RNA突变。
病例报告。
一名66岁女性，因运动不耐受和足部感觉异常出现行走困难4年。临床检查结果正常。她已故的母亲有类似的行走困难，但她的姐姐和2个孩子未受影响。
肌肉活检显示细胞色素c氧化酶活性存在明显的组织化学缺陷，促使对线粒体DNA进行分子研究，结果显示线粒体苯丙氨酸转运RNA基因可变环中有一个新的母系遗传突变。这种622G>A转换是异质性的，并与单纤维中的细胞色素c氧化酶缺乏相关。
该病例表明，即使是患有迟发性、轻度神经肌肉症状的老年患者，也应考虑线粒体基因组的原发性缺陷。
