Molecular Characterization of Pontocerebellar Hypoplasia

项目摘要/摘要 桥小脑发育不全(PCH)是一组以隐性遗传为主的异质性儿童脑病 表现出神经发育受损和神经退行性变的特征的疾病。 PCH的特征是严重的年龄相关性神经损害，并有显著的放射学特征。 脑桥和小脑体积减少，并伴有脑干和小脑神经元丢失。目前 已知PCH中有32个基因发生突变，但还有更多的基因有待发现，分子水平 人们对这一机制知之甚少。其中一些基因涉及蛋白质合成的关键步骤和 包括tRNA和mRNA剪接在内的基因组完整性，表明细胞内环境平衡受到破坏 功能，但仍有许多问题：1]还有多少遗传亚型有待发现？2] 为什么广泛表达的基因的丢失倾向于神经元？3]有收敛吗？ PCH的分子途径？在过去的5年中，我们已经：1]发展了我们独特的PCH队列 患者，包括248个家庭，其中132个仍然没有分子原因。2]应用了一系列 基因组学和转录组学方法发现几个新基因的突变，包括 TOE1、TBC1D23、PRP17和PPIL1导致特定的PCH亚型。3]发现了RNA中的缺陷 剪接和基因组完整性是潜在原因。4]发现了第一个剪接体蛋白 突变。5]揭示了新的基因型表型相关性。在我们的初步数据中，我们有：1] 获得了推进全基因组测序的资源，以评估我们剩余的未破案件。 2]确定了另外10个新基因是PCH的原因。值得注意的是，我发现了六本小说 导致编码剪接体蛋白。4)发现R-环堆积是DNA损伤的原因 突变会导致基因毒性应激。此应用程序的目标是：1]确定剩余的 多氯联苯的“可发现”基因。2]从功能上验证致病框架内的突变。3] 检验PCH基因缺失通过R环堆积导致神经细胞死亡的假设， DNA损伤和基因毒性应激。这项工作将有助于深入了解AND的原因和机制 婴幼儿脑病的重要病因及选择性神经元机制的揭示 发育性脑病的脆弱性和儿童神经退行性变。

PROJECT SUMMARY/ABSTRACT Pontocerebellar hypoplasia (PCH) is a heterogeneous group of mostly recessive pediatric brain disorders that show features of both impaired neurodevelopment and presence of neurodegeneration. PCH is characterized by severe age-dependent neurological impairment, and notable radiographic volume loss of the pons and cerebellum with loss of brainstem and cerebellar neurons. Currently there are 32 genes known mutated in PCH, but still more genes await to be discovered, and molecular mechanisms are poorly understood. Some of the genes implicate key steps in protein synthesis and genomic integrity including tRNA and mRNA splicing, suggesting disruption to homeostatic cellular functions, but many questions remain: 1] How many genetic subtypes remain to be discovered? 2] Why do loss of broadly expressed genes predispose specifically to neurons? 3] Are there convergent molecular pathways for PCH? Over the past 5 years, we have: 1] Grown our unique cohort of PCH patients, containing 248 families including 132 still without a molecular cause. 2] Applied a range of genomics and transcriptomics methods to uncovered mutations in several novel genes including TOE1, TBC1D23, PRP17 and PPIL1 leading to specific PCH subtypes. 3] Revealed defects in RNA splicing and genome integrity as underlying causes. 4] Uncovered the first spliceosome protein mutations. 5] Revealed new genotype phenotype correlations. In our preliminary data we have: 1] Secured resources to advance whole genome sequencing to evaluate our remaining unsolved cases. 2] Identified a further ten new genes as causes for PCH. 3] Remarkably, found that six of the novel causes encode spliceosome proteins. 4] Uncovered R-loop accumulation as a cause of DNA damage by which mutations lead to genotoxic stress. The goal of this application is to: 1] Identify the remaining ‘discoverable’ genes for PCH. 2] Functionally validate mutations within a pathogenic framework. 3] Test the hypothesis that PCH gene loss leads to neurons cell death through R-loop accumulation, DNA damage and genotoxic stress. This work will lead to insight into causes and mechanisms of an important cause of infantile encephalopathy, and uncover mechanisms of selective neuronal vulnerability and pediatric neurodegeneration underlying developmental brain disease.