Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation: clinical and genetic characterization and target for therapy
Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation: clinical and genetic characterization and target for therapy
复制标题
DOI：
10.1093/brain/awu026
复制
发表时间：
2014-04-01
期刊：
影响因子：
14.5
通讯作者：
van der Knaap, Marjo S.
中科院分区：
文献类型：
--
作者：
van Berge, Laura;Hamilton, Eline M.;van der Knaap, Marjo S.
白质脑病伴脑干和脊髓受累以及乳酸升高是由编码线粒体乙酰-tRNA合成酶的基因DARS 2的隐性突变引起的疾病。最近的观察表明，该疾病的表型范围比最初想象的要广得多。目前没有治疗方法。我们研究的目的是（i）探索可能的基因型-表型相关性;和（ii）鉴定调节DARS 2内含子2中剪接位点突变的潜在治疗剂，所述剪接位点突变存在于几乎所有患者中。在截至2012年12月的阿姆斯特丹和赫尔辛基数据库中，对78例携带两种DARS 2突变的患者进行了一项横断面观察性研究。通过问卷调查收集临床信息。对这些患者和先前发表的患者中的DARS 2突变进行了清点。开发了一种测定法来评估细胞中线粒体乙酰-tRNA合成酶的活性。使用荧光报告系统，我们筛选调节DARS 2剪接的药物。获得66例患者的临床资料。临床严重程度从婴儿期发病、快速致死性疾病到成人期发病、缓慢和轻度疾病不等。最常见的表型特征为儿童期发病和缓慢的神经功能恶化。完全依赖轮椅是罕见的，通常在成年后开始。总共鉴定了60种不同的DARS 2突变，其中13种以前从未报道过。42例中除4例为复合杂合子外，其余均为复合杂合子。94%的患者在内含子2中存在剪接位点突变。共享相同的两个突变的患者组太小，无法进行基因型-表型相关性的正式评估。然而，一些突变组合始终与轻度表型相关。患者细胞中线粒体乙酰-tRNA合成酶活性强烈降低。在筛选的化合物中，藜芦苷被鉴定为最有效的DARS 2剪接调节剂。总之，脑干和脊髓受累及乳酸升高的白质脑病的表型谱很广，但大多数情况下，这种疾病的病程相对缓慢和温和。现有的证据表明，基因型影响表型，但由于大量的私人突变，需要大量的患者来证实这一点。患者细胞中线粒体乙酰-tRNA合成酶的活性显著降低。复合筛选建立了剪接位点突变可以受到影响的“原理证明”。这一发现对于未来的治疗策略是有希望的。
Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is a disorder caused by recessive mutations in the gene DARS2, which encodes mitochondrial aspartyl-tRNA synthetase. Recent observations indicate that the phenotypic range of the disease is much wider than initially thought. Currently, no treatment is available. The aims of our study were (i) to explore a possible genotype-phenotype correlation; and (ii) to identify potential therapeutic agents that modulate the splice site mutations in intron 2 of DARS2, present in almost all patients. A cross-sectional observational study was performed in 78 patients with two DARS2 mutations in the Amsterdam and Helsinki databases up to December 2012. Clinical information was collected via questionnaires. An inventory was made of the DARS2 mutations in these patients and those previously published. An assay was developed to assess mitochondrial aspartyl-tRNA synthetase enzyme activity in cells. Using a fluorescence reporter system we screened for drugs that modulate DARS2 splicing. Clinical information of 66 patients was obtained. The clinical severity varied from infantile onset, rapidly fatal disease to adult onset, slow and mild disease. The most common phenotype was characterized by childhood onset and slow neurological deterioration. Full wheelchair dependency was rare and usually began in adulthood. In total, 60 different DARS2 mutations were identified, 13 of which have not been reported before. Except for 4 of 42 cases published by others, all patients were compound heterozygous. Ninety-four per cent of the patients had a splice site mutation in intron 2. The groups of patients sharing the same two mutations were too small for formal assessment of genotype-phenotype correlation. However, some combinations of mutations were consistently associated with a mild phenotype. The mitochondrial aspartyl-tRNA synthetase activity was strongly reduced in patient cells. Among the compounds screened, cantharidin was identified as the most potent modulator of DARS2 splicing. In conclusion, the phenotypic spectrum of leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is wide, but most often the disease has a relatively slow and mild course. The available evidence suggests that the genotype influences the phenotype, but because of the high number of private mutations, larger numbers of patients are necessary to confirm this. The activity of mitochondrial aspartyl-tRNA synthetase is significantly reduced in patient cells. A compound screen established a 'proof of principle' that the splice site mutation can be influenced. This finding is promising for future therapeutic strategies.