Tallinn Children's Hospital, Tallinn, Estonia.
Pediatr Neurol. 2010 Mar;42(3):227-30. doi: 10.1016/j.pediatrneurol.2009.10.004.
Mutations in the SCO2 gene [SCO cytochrome oxidase deficient homolog 2 (yeast)] causing cytochrome c oxidase deficiency have been reported in at least in 26 patients with fatal infantile cardioencephalomyopathy. Mutation 1541G > A affecting protein stability is associated with the majority of cases, and the other 11 described mutations have more serious deleterious structural consequences for the protein product. Reported here is a novel case caused by compound heterozygosity of SCO2. The child presented at the age of 3 weeks with failure-to-thrive, muscular hypotonia, hypertrophic cardiomyopathy, and lactic acidemia. Leigh syndrome was diagnosed based on magnetic resonance imaging findings. Immunohistochemical and enzymatic investigations on muscle indicated totally absent cytochrome c oxidase activity. Both parents had mild mental retardation. Sequence analysis in the patient and in his parents revealed heterozygous mutation c.418G > A in exon 2 inherited from the father and maternally inherited heterozygous insertion of 19bp at position 17 in the coding region of the SCO2 gene. Respiratory chain enzyme activity measurements indicated normal activity in both parents, although the mother's cytochrome c oxidase activity was lower. This gene may be involved in the etiology of the mother's mental retardation.
SCO2 基因[细胞色素 c 氧化酶缺陷同源物 2（酵母）]中的突变导致细胞色素 c 氧化酶缺乏已在至少 26 例致命性婴儿心肌脑肌病患者中报道。影响蛋白稳定性的突变 1541G > A 与大多数病例相关，而其他 11 种描述的突变对蛋白产物具有更严重的有害结构后果。这里报告了一例由 SCO2 复合杂合性引起的新病例。该患儿在 3 周龄时因生长不良、肌肉张力减退、肥厚型心肌病和乳酸性酸中毒就诊。根据磁共振成像结果诊断为 Leigh 综合征。肌肉的免疫组化和酶学研究表明细胞色素 c 氧化酶活性完全缺失。父母双方均有轻度智力障碍。对患儿及其父母的序列分析显示，从父亲遗传的第 2 外显子 c.418G > A 杂合突变和从母亲遗传的编码区 17 位 19bp 的插入杂合子。呼吸链酶活性测量表明父母双方的活性均正常，尽管母亲的细胞色素 c 氧化酶活性较低。该基因可能与母亲智力障碍的病因有关。
