Role of somatic mosaicism in autism, schizophrenia, and bipolar disorder brain

项目摘要/摘要 这项拟议的研究的广泛、长期的目标是识别发生在 自闭症谱系障碍(ASD)、精神分裂症(SZ)和双相情感障碍患者的脑区 (BD)。最终，体细胞突变的发现和特征可能有助于我们理解 这些疾病的病因，并最终导致改进的治疗策略和诊断标记物。 ASD、SZ和BD都是常见的神经精神疾病，有很大的遗传基础(与 每种疾病的估计遗传率约为75%至80%)。然而，相对较少的DNA变异体 已确定在病因学中具有因果作用。我们假设体细胞嵌合体的发生-- 受孕后选定身体区域的突变--发生在大脑中，并与ASD的病因有关， SZ和BD。具体目标1是确定整个大脑和大脑的体细胞镶嵌突变的性质和程度 明显正常的人的身体样本中的身体区域。我们将评估四个类别的 体细胞变异：(1)单核苷酸变异(SNV)，(2)包括拷贝数的结构变异(SVS) 变异，(3)L1逆转座子事件，和(4)线粒体异质性。这些类型的变化将是 使用全基因组测序(第1年和第2年)、单分子成像和DNA纳米通道进行检测 (第2年)和单核苷酸多态(SNP)阵列。样本包括大脑区域(例如前额叶 大脑皮层和小脑)和器官(如心脏和肾脏)。在鉴定了体细胞变异后，我们将执行 严格的验证。具体目标2是确定基因组DNA中体细胞嵌合体的性质和程度 来自患有ASD、SZ和BD的个体。相同的发现和验证方法将应用于 目标1.具体目标3是对体细胞变异进行功能分类，特别是那些被预测为 干扰以前与这些疾病有牵连的基因的功能。一种方法是单细胞rna-seq。 (为了确定突变对转录的影响，并推断来源的细胞类型 体细胞变异体)。另一种方法是使用来自诱导多能干细胞(Ipscs)的神经元(或胶质细胞)。 以及稳定表达所述体细胞变体的野生型或突变型。这些研究将有助于建立 体细胞突变在神经精神障碍中的作用，包括这种突变的功能后果 变种。

PROJECT SUMMARY/ABSTRACT The broad, long-term objective of the proposed research is to identify somatic genetic mutations that occur in brain regions of individuals with autism spectrum disorder (ASD), schizophrenia (SZ), and bipolar disorder (BD). Ultimately the discovery and characterization of somatic mutations may help us to understand the etiology of these disorders and eventually lead to improved therapeutic strategies and diagnostic markers. ASD, SZ, and BD are all commonly occurring neuropsychiatric disorders that have a large genetic basis (with estimated heritability of ~75% to 80% for each condition). However, relatively few DNA variants have been identified that have causal roles in the etiology. We hypothesize that somatic mosaicism--the occurrence of mutations in selected body regions after conception--occurs in brain and contributes to the etiology of ASD, SZ, and BD. Specific Aim 1 is to identify the nature and extent of somatic mosaic mutations across brain and body regions in postmortem samples from apparently normal individuals. We will assess four categories of somatic variation: (1) single nucleotide variants (SNVs), (2) structural variants (SVs) including copy number variants, (3) L1 retrotransposition events, and (4) mitochondrial heteroplasmy. These types of variation will be detected using whole genome sequencing (Years 1 and 2), single molecule imaging with DNA nanochannels (Year 2), and single nucleotide polymorphism (SNP) arrays. Samples include brain regions (e.g. prefrontal cortex and cerebellum) and organs (e.g. heart and kidney). After identifying somatic variants we will perform rigorous validation. Specific Aim 2 is to identify the nature and extent of somatic mosaicism in genomic DNA from individuals with ASD, SZ, and BD. The same approaches for discovery and validation will be applied as in Aim 1. Specific Aim 3 is to functionally categorize somatic variants, particularly those that are predicted to disrupt the functions of genes previously implicated in those disorders. One approach is single-cell RNA-seq (to determine the consequence of the mutation on transcription, and to infer the cell type of origin of the somatic variant). Another approach uses neurons (or glia) derived from induced pluripotent stem cells (iPSCs) and stably expressing the wildtype or mutant forms of the somatic variants. These studies will help to establish the role of somatic mutation in neuropsychiatric disorders, including the functional consequences of such variation.