Genetic Movement Disorders: Etiologies and Pathogeneses

这项应用建议识别遗传性运动障碍的分子病因并阐明其影响 将致病变种作为改善诊断和开发靶向的重要步骤 治疗。本项目研究的疾病类别，包括帕金森氏病(PD)和相关疾病 综合征、共济失调、痉挛截瘫和舞蹈性或肌张力障碍，都是遗传上的。 异质的。我们已经确定了多种运动障碍的潜在基因，其中一些是 将重点放在这一建议中，并开始研究它们的发病机制。还有更多的致病基因有待研究 被发现了。我们建议1)继续确定个人和家庭的遗传特征 不明原因的运动障碍；2)使用最先进的基因图谱和下一代测序 发现运动障碍新基因的技术；以及3)研究运动障碍的致病机制 使用患者组织、患者来源的干细胞模型和果蝇模型的变体。提案建立了 关于已建立的协同合作和多方面的临床、病理、基础科学和 调查人员和合作者的翻译专业知识。它还利用了两个 经过30多年的确定、广泛表征和延续的大量样本收集 (神经遗传学和PD储存库)。 我们的疾病基因识别方法结合了传统的连锁或血统识别(IBD)。 分析以确定所有受影响的家庭成员所共有的基因组区域，以及外显子组或基因组 测序和拷贝数变异(CNV)分析以确定与 受影响的亲属。统计遗传学的进步和更密集的标记面板的使用使其成为可能 在较小的家庭中进行这样的研究，更强大的生物信息学工具提供逐步过滤 对可能的致病变异进行优先排序以供进一步研究的方法。一种带有疾病的变异体的种族隔离 单家系和在其他家系和大型公共可获得的相同基因突变的鉴定 具有相同疾病的零星病例的数据集提供了对该基因负责的验证 疾病。然后，可以通过机制研究来研究疾病的发病机制。这种方法导致了 与我们在解析遗传神经疾病方面一贯高效的记录有关。 对于功能研究，我们集中在RAB39Bα-突触核病症，ATP6AP2tau病，和SAMD9L 共济失调、全血细胞减少和自身免疫综合征，这三种疾病的致病基因我们都发现了，以及 GBA，这是已知的特发性帕金森病最强的遗传风险因素。这四个基因参与了 内溶酶体运输和自噬，经常与帕金森病和其他神经退行性变有关的途径 精神错乱。通过分析人类尸检脑组织样本中的基因表达，我们将识别脆弱的细胞 类型和特征的区域特定的变化，推动病理。神经细胞和神经胶质细胞从 患者的诱导多能干细胞(IPSC)将被用来研究致病变异对患者的影响 这些基因中的每一个，如ATP6AP2/V-ATPase功能缺陷之间的联系，都受到损害 易于聚集的tau蛋白的自噬和周转。自噬将被药物诱导为 探索减轻tau病理，提高神经元存活率。果蝇和iPSC型号将被用来 研究RAB39B和ATP6AP2蛋白是如何与GBA相互作用的，以及RAB39B中的致病变异是如何发生的， ATP6AP2和SAMD9L影响内酶体转运。 除了基因发现对患有特定疾病的患者意味着什么之外，每个新基因 有助于我们理解神经退行性变中复杂的蛋白质-蛋白质相互作用。 此外，从它们的生化途径和蛋白质复合体中，每个新基因都可以发现额外的 这些疾病的候选基因也可以被认为是干预的目标。

This application proposes to identify molecular etiologies of heritable movement disorders and elucidate effects of pathogenic variants as important steps towards improving diagnoses and development of targeted therapies. The categories of disease studied in this project, including Parkinson’s disease (PD) and related syndromes, ataxias, spastic paraplegias, and choreiform or dystonic disorders, are all genetically heterogeneous. We have identified the underlying genes for multiple movement disorders, some of which are a focus in this proposal, and initiated studies on their pathogeneses. Many more contributing genes remain to be discovered. We propose to 1) continue to ascertain and characterize individuals and families with genetically unattributed movement disorders; 2) use state-of-art gene mapping and next-generation sequencing technologies to discover new genes for movement disorders; and 3) investigate pathogenic mechanisms of variants using patient tissues, patient-derived stem cell models, and Drosophila models. The proposal builds on established synergistic collaborations and multifaceted clinical, pathological, basic science, and translational expertise of the Investigators and Collaborators. It also leverages the invaluable resources of two large collections of samples ascertained, extensively characterized, and extended over 30 years (Neurogenetics and PD repositories). Our approach to disease gene identification combines traditional linkage or identity-by-descent (IBD) analysis to identify genomic regions shared by all affected family members, together with exome or genome sequencing and copy number variation (CNV) analysis to identify variants in the linkage/IBD region shared by affected relatives. Advances in statistical genetics and use of denser marker panels make it possible to perform such studies in smaller families and more powerful bioinformatics tools offer a stepwise filtering approach to prioritize likely pathogenic variants for further study. Cosegregation of a variant with disease in single families and identification of mutations in the same gene in other families and large publicly available datasets of sporadic cases with the same disorder provide validation that the gene is responsible for the disease. Disease pathogenesis can then be investigated through mechanistic studies. This approach has led to our documented record of consistent productivity in parsing genetic neurologic disorders. For functional studies, we focus on the RAB39B α-synucleinopathy, the ATP6AP2 tauopathy, and SAMD9L ataxia, pancytopenia and autoimmunity syndrome, three disorders whose causative genes we discovered, and GBA, which is the strongest known genetic risk factor for idiopathic PD. These four genes participate in endolysosomal trafficking and autophagy, pathways frequently implicated in PD and other neurodegenerative disorders. By analysis of gene expression in human autopsy brain samples, we will identify vulnerable cell types and characterize region-specific changes that drive pathology. Neural and glial cells reprogrammed from induced pluripotent stem cells (iPSC) of patients will be used to investigate effects of pathogenic variants in each of these genes, such as a connection between deficiency in ATP6AP2/V-ATPase function, impaired autophagy, and turnover of aggregation-prone tau protein. Autophagy will be pharmacologically induced to explore mitigation of tau pathology and improve neuronal survival. Drosophila and iPSC models will be used to investigate how RAB39B and ATP6AP2 proteins interact with GBA and how pathogenic variants in RAB39B, ATP6AP2, and SAMD9L influence endolysosomal trafficking. Beyond the implication of gene discovery for patients who suffer from a particular disorder, each new gene contributes to our understanding of the complex protein-protein interactions involved in neurodegeneration. Furthermore, from their biochemical pathways and protein complexes each new gene can uncover additional candidate genes for the disorders that can also be considered as targets for intervention.