Personalized Functional Genomics for Mitochondrial Encephalopathy Gene Discovery

项目摘要 线粒体疾病是一种常见的遗传性疾病，发病率为1/5000，可影响每 器官系统，因此表现出广泛的临床表型。最常见的是神经性和 神经肌肉功能障碍，表现为神经变性、癫痫发作、共济失调、慢性进行性 外眼肌麻痹(CPEO)和低眼压。儿童期发病的线粒体疾病最常见的结果是 来自核基因组的突变；然而，大多数病例仍然没有分子诊断 而且没有有效的治疗方法，因此迫切需要确定导致这些疾病的基因异常 精神错乱。我们提出了一种个性化的功能基因组学方法，结合全基因组测序， 转录组学、代谢组学和细胞内线粒体功能图谱鉴定有效的新基因 线粒体疾病基因和变异体。我们将利用多元经济战略来确定 致病基因和致病机制的阐明：1.患者的全基因组测序 转录学和代谢组学2.基于细胞的基因和途径的功能研究 病人。通过我们的国际合作者网络，我们收集了临床上有 确诊为没有分子诊断的原发性线粒体脑病。适用于以下患者 已经有WES/WGS，但没有分子诊断，我们将重新解释这些数据并利用我们的 能够理解ABMGG诊断指南以外的内容。此外，我们还进行了一项类似的工作来确定 通过对贝勒遗传学诊断实验室的临床外显子组数据库进行数据挖掘的疾病基因 其中已知对线粒体功能至关重要但尚未被证明为 对患者的致病原因进行突变分析。基因因果关系将通过一系列 包含基因策略的线粒体功能谱基于细胞的疾病模拟实验 击倒、高通量诱变、敲入和cdna互补研究。我们将利用这一点 用于测试在我们的测序工作中确定的不确定重要性的变体的功能的技术 以及通过合作者、诊断实验室和公共领域获得的信息。这项工作将 创造了前所未有的细胞线粒体功能和功能的系统化分析资源- 确认了致病分子缺陷。这些致病基因和变异体的阐明将 立即提高对疑似线粒体疾病儿童的分子诊断潜力。 此外，通过识别原发线粒体脑病的致病基因，我们将赋予 科学界关注的是神经和神经退行性疾病，这些疾病有更复杂的 病因学，通过传递基因和途径，进一步研究这些全球 健康问题。

Project Summary Mitochondrial disease is a commonly occurring inherited condition, incidence 1/5000, which can affect every organ system and thus exhibits a broad range of clinical phenotypes. The most common are neurological and neuromuscular dysfunction that manifest as neurodegeneration, seizures, ataxia, chronic progressive external opthalmoplegia (CPEO), and hypotonia. Childhood-onset mitochondrial disease most often results from mutations in the nuclear genome; however, the majority of cases remain without a molecular diagnosis and no effective treatments thus underscoring the critical need to identify the genetic aberrations driving these disorders. We propose a personalized functional genomics approach combining genome-wide sequencing, transcriptomics, metabolomics and mitochondrial functional profiling in cells to identify validated novel mitochondrial disease genes and variants. We will leverage a multi-omic strategy for identifying the pathogenic genes and elucidating pathomechanisms: 1. Genome-wide sequencing of patients coupled with transcriptomics and metabolomics 2. Cell-based functional studies of genes and pathways identified in patients. Through our international network of collaborators we have collected patients with clinically confirmed primary mitochondrial encephalopathy who do not have a molecular diagnosis. For patients who have already had WES/WGS but no molecular diagnosis we will re-interpret these data and leverage our ability to interpret beyond ABMGG guidelines for diagnosis. Additionally, we have a parallel effort to identify disease genes through datamining the clinical exome database at Baylor Genetics diagnostic laboratory wherein genes that are known to be essential for mitochondrial function but are not yet demonstrated as disease causing are analyzed for mutations in patients. Gene causality will be determined through a series of cell-based disease modeling experiments of mitochondrial functional profiling that include strategies of gene knock down, high-throughput mutagenesis knock-in, and cDNA complementation studies. We will utilize this technology to test the functionality of variants of uncertain significance identified in our sequencing efforts as well as those obtained through collaborators, diagnostic laboratories, and the public domain. This work will generate an unprecedented resource of systematic profiling of cellular mitochondrial function and functionally- confirmed pathogenic molecular defects. The elucidation of these pathogenic genes and variants will immediately improve the molecular diagnostic potential for children with suspected mitochondrial disease. Moreover, by identifying the pathogenic genes for primary mitochondrial encephalopathy we will empower the scientific community focused on neurological and neurodegenerative disorders, which have a more complex etiology, by delivering genes and pathways for further study of the pathogenetic mechanisms of these global health problems.