Translational activator of cytochrome c oxidase I (TACO1) is a mitochondrial translation factor involved in mitochondria-encoded cytochrome c oxidase subunit I (MT-CO1) synthesis.^1,2 Loss-of-function mutations in the TACO1 gene cause respiratory chain complex IV deficiency. Clinically heterogeneous human diseases are due to cytochrome c oxidase (COX) deficiency, ranging from Leigh syndrome to myopathy, deafness, or ataxia. Recently, 2 different TACO1 mutations have been identified in 3 families with late-onset Leigh syndrome and a leukoencephalopathy involving predominantly basal ganglia and cystic changes.^3,4 Here, we report a subject carrying a novel homozygous truncating mutation in the TACO1 gene and presenting an adult-onset slowly progressive spastic paraparesis with cognitive impairment and a subcortical U-fiber leukoencephalopathy.

细胞色素C氧化酶I（TACO1）的翻译激活剂是一种线粒体翻译因子，参与线粒体编码的细胞色素C氧化酶I（MT-CO1）的合成。^1,2 TACO1基因的功能丧失突变导致呼吸链复合物IV缺乏。临床上异类的人类疾病是由于细胞色素C氧化酶（COX）缺乏所致，范围从Leigh综合征到肌病，耳聋或共济失调。最近，在3个晚期Leigh综合征和主要涉及基底神经节和囊性变化的白脑病的家庭中，已经鉴定出2个不同的TACO1突变。^3,4在这里，我们报告一个受试者在TACO1中携带了一个新的纯合截短突变 基因和呈现成人发作缓慢进行性痉挛性轻瘫，伴有认知障碍和皮层下U纤维白质脑病。