Human neurobehavioral phenotypes associates with the extended PWS/AS domain

描述（由申请人提供）： 项目概要/摘要。该提案的长期目标是定义染色体15 q11-q13上从断点1（BP 1）延伸到断点5（BP 5）的扩展Prader-Willi/Angelman结构域的基因型/表型相关性，特别强调BP 4-BP 5区域，其中缺失与精神发育迟滞，自闭症，癫痫，精神分裂症和双相情感障碍相关。遗传分析将集中在拷贝数变异（CNVs）删除或复制多个连续基因和单个基因内的点突变，特别是CHRNA 7。该项目以前的工作集中在Prader-Willi综合征（PWS）和Angelman综合征（AS），分别由父亲和母亲缺乏该领域的中心部分引起。现在的重点正在扩大，包括自闭症引起的重复这一地区和研究表型相关的侧翼部分的域，BP 1至BP 2和BP 4至BP 5。染色体15q13.3（BP 4-BP 5）的缺失去除了6个相邻的基因，较小的缺失去除了CHRNA 7和相邻基因的一个外显子。目的1是确定BP 4-BP 5区域的基因型/表型关系，重点是CHRNA 7基因。目的1a是通过病例对照研究确定15q13.3和CHRNA 7重复是病理性的还是良性的。目的1b是确定与15q13.3和CHRNA 7缺失相关的表型异质性的基础，主要关注但不限于各种遗传修饰剂的作用。目的1c是在特别高风险的样本中寻找CHRNA 7的功能丧失点突变，例如患有癫痫和精神分裂症或癫痫和双相情感障碍的NIMH样本。目的2是确定BP 1-BP 2区域和其中的四个基因的基因型/表型关系。目的3是确定BP 1/BP 2至BP 3区域的重复的起源效应的亲本的分子基础，所述重复在母体染色体上时通常导致自闭症，并且在父体染色体上时通常是良性的。这一目标将强调表达分析（越来越多地依赖于RNA-Seq）和比较15 q11-q13区域与对照的重复的人脑组织的表观遗传学研究。目的4是确定snoRNA HBII-85簇的功能，因为现在有相对强有力的证据表明，该snoRNA簇的父本缺陷导致PWS表型的主要组分。这一目标将集中在表达的全基因组分析和选择性剪接和RNA编辑（再次使用RNA-Seq）在人类和小鼠大脑缺乏HBII-85的表达。基于生物信息学分析，已鉴定出一系列靶候选基因，并计划进行进一步的生物信息学分析。这些候选基因的表达将使用RT-PCR在来自小鼠和人类的对照和PWS脑中进行研究，以分析可变剪接和RNA编辑。

DESCRIPTION (provided by applicant): Project Summary/Abstract. The long-term objectives of this proposal are to define genotype/phenotype correlations for the extended Prader-Willi/Angelman domain on chromosome 15q11-q13 that stretches from Breakpoint 1 (BP1) to Breakpoint 5 (BP5), with special emphasis on the BP4-BP5 region where deletions are associated with mental retardation, autism, epilepsy, schizophrenia, and bipolar disorder. Genetic analysis will focus both on copy number variations (CNVs) deleting or duplicating multiple contiguous genes and on point mutations within individual genes, especially CHRNA7. Previous work on this project has focused on Prader- Willi syndrome (PWS) and Angelman syndrome (AS), caused by paternal and maternal deficiency, respectively, for the central portion of the domain. The focus is now being broadened to include autism caused by duplications of this region and to study phenotypes associated with the flanking portions of the domain, BP1 to BP2 and BP4 to BP5. Deletions of chromosome 15q13.3 (BP4-BP5) remove six contiguous genes, and a smaller deletion removes CHRNA7 and one exon of an adjacent gene. Aim 1 is to determine genotype/phenotype relationships for the BP4-BP5 region with emphasis on the CHRNA7 gene. Aim 1a is to determine if the 15q13.3 and CHRNA7 duplications are pathological or benign using case control studies. Aim 1b is to identify the basis for the phenotypic heterogeneity associated with the 15q13.3 and CHRNA7 deletions focusing primarily but not exclusively on various genetic modifier effects. Aim 1c is to search for loss-of- function point mutations in CHRNA7 in particularly high risk samples such NIMH samples with both epilepsy and schizophrenia or both epilepsy and bipolar disorder. Aim 2 is to determine genotype/phenotype relationships for the BP1-BP2 region and the four genes therein. Aim 3 is to determine the molecular basis for the parent of origin effects of duplications of the BP1/BP2 to BP3 region which typically cause autism when on a maternal chromosome and are usually benign when on the paternal chromosome. This aim will emphasize expression analysis (increasingly relying on RNA-Seq) and epigenetic studies of human brain tissue comparing duplications of the 15q11-q13 region with controls. Aim 4 is to determine the function of the snoRNA HBII-85 cluster, because there is now relatively strong evidence that paternal deficiency for this snoRNA cluster causes the major components of the PWS phenotype. This aim will focus on genome-wide analysis of expression and on alternative splicing and RNA editing (again using RNA-Seq) in human and mouse brain lacking expression of HBII-85. A series of target candidate genes have been identified by others based on bioinformatic analysis, and further bioinformatic analysis is planned. The expression of these candidate genes will be studied in control and PWS brain from mouse and human using RT-PCR to analyze alternative splicing and RNA editing.