Biological correlates of altered brain growth in autism

描述（由申请人提供）：自闭症谱系障碍（ASD）中持续复制的生物表型是生命最初几年的头围（HC）较大。我们假设ASD患者大脑体积的增加是由于神经细胞固有的遗传变化导致细胞增殖和/或分化的动力学改变。在本申请中，我们将从患有ASD的个体和通常患有大头畸形的儿童的皮肤成纤维细胞中获得诱导多能干细胞（iPSC）。全基因组研究检查从iPSC分离的DNA中的结构遗传变异，与相同个体的淋巴细胞相比，将确保重编程细胞的遗传稳定性。在具体目标1中，从23名患有ASD的参与者和11名典型发育的患有大头畸形的个体获得的iPSC系将通过配对末端作图（PEM）和阵列捕获和测序在细胞增殖、细胞存活和基因组范围的结构变异（例如拷贝数变异（CNV））方面进行表征。在特定目标2中，将在从相同的23名ASD参与者和11名典型发育个体以及有限数量的家庭成员中采集的血液淋巴细胞DNA中获得全基因组CNV以及序列变异数据集。这将涉及（1）PEM（2）阵列捕获外显子和启动子区域并测序，以及（3）逆转录元件模式的全基因组定位。这项研究中出现的对ASD潜在重要的遗传区域将通过在两个更大的ASD先证者及其家庭成员的独立队列中进行靶向重测序来验证，每个队列包括约500名个体。我们项目的近期目标是创建一个新的资源和分析工具。比较iPSC和血液样本中DNA序列变异的遗传学研究对于确定iPSC基因组结构与患者中鉴定的基因组结构相对应至关重要。在未来的研究中，在该项目中产生的iPSC系将沿着神经谱系特异性分化沿着，并进一步分析其增殖，分化和存活，使我们能够测试ASD中大脑大小的增加是否归因于细胞增殖和/或分化的动力学改变。这些来自iPSC系的神经细胞将在转录和表观遗传水平上进行表征，本项目中提出的基本表征将提供必要的平台。我们的最终目标是将神经生物学表型和神经分化过程中基因表达的变化与个体的潜在遗传结构联系起来，以阐明疾病的发病机制。因此，拟议的项目将提供一个资源，在未来的研究中，基因组序列，基因表达的调控和强度，细胞（生物）后果和患者行为的相关性。 公共卫生相关性：该项目将使用皮肤活检获得的细胞，从患有自闭症谱系障碍（ASD）的个体和典型发育中的儿童中开发多能细胞（iPSC）。我们将为每个个体生产几个iPSC系，并对其生物学和结构遗传变异进行表征。我们的目标是创建一个资源和分析工具，这将使我们能够检查自闭症谱系障碍的神经元分化。

DESCRIPTION (provided by applicant): A consistently replicated biological phenotype in autism spectrum disorders (ASD) is a larger head circumference (HC) in the first years of life. We hypothesize that increased brain size in ASD is attributable to altered dynamics of cell proliferation and/or differentiation due to genetic changes intrinsic to neural cells. In this application, we will derive induced pluripotent stem cells (iPSC) from skin fibroblasts in individuals with ASD and typically developing children with macrocephaly. Whole genome studies examining structural genetic variation in DNA isolated from iPSC as compared to lymphocytes of the same individuals will ensure genetic stability of the reprogrammed cells. In Specific Aim 1, iPSC lines obtained from 23 participants with ASD and 11 typically developing individuals with macrocephaly will be characterized with respect to cell proliferation, cell survival and genome wide structural variation such as copy number variations (CNVs) by paired end mapping (PEM) and array capture and sequencing. In Specific Aim 2, genome wide CNV as well as sequence variation datasets will be obtained in blood lymphocyte DNA taken from the same 23 participants with ASD and 11 typically developing individuals, plus a limited number of their family members. This will involve (1) PEM (2) array capture for exons and promoter regions with sequencing, and (3) genome-wide mapping of retroelement patterns. Genetic regions potentially important for ASD that will emerge from this study will be validated by targeted resequencing in two larger, independent cohorts of ASD probands and their family members, each comprising about 500 individuals. The immediate goal of our project is to create a new resource and analytical tool. The genetic studies comparing DNA sequence variation in iPSC and blood samples are essential to establish that the iPSC genomic structure corresponds to that identified in the patients. In future studies, iPSC lines generated in this project will be specifically differentiated along the neural lineage and further analyzed with respect their proliferation, differentiation and survival, allowing us to test whether increased brain size in ASD is attributable to altered dynamics of cell proliferation and/or differentiation. These neural cells derived from iPSC lines will be characterized at the transcript and epigenetic levels, for which the basic characterization proposed in this project will provide a necessary platform. Our ultimate goal is to link neurobiological phenotypes and changes in gene expression during the neural differentiation process, with the underlying genetic structure of the individuals to elucidate disease pathogenesis. Therefore, the proposed project will provide a resource for correlating, in future studies, genomic sequence, regulation and intensity of gene expression, cellular (biological) consequences, and patient behavior. PUBLIC HEALTH RELEVANCE: This project will develop lines of pluripotent cells (iPSC) from individuals with autism spectrum disorders (ASD) with macrocephaly and typically developing children, using cells obtained by a skin biopsy. We will produce several iPSC lines per individual and characterize them with respect to their biology and their structural genetic variation. The aim is create a resource and analytical tool, which will allow us to examine neuronal differentiation in autism spectrum disorders.