A Genomic Approach to Studying Repeat Instability in Schizophrenia

研究精神分裂症重复不稳定性的基因组方法

• 批准号: 7498406
• 负责人: Diane Elaine Dickel
• 金额: $ 3.12万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-16 至 2010-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7498406
• 关键词: Alleles; Amino Acid Substitution; Bioinformatics; Biological; Capillary Electrophoresis; Code; DNA; Development; Diagnostic tests; Disease; Equilibrium; Event; Family; Genes; Genetic; Genome; Genomics; Genotype; Goals; Homozygote; Individual; Lead; Length; Loss of Heterozygosity; Mental disorders; Morphologic artifacts; Mutation; National Institute of Mental Health; Nucleic Acid Regulatory Sequences; Oligonucleotides; Paternal Age; Pentanucleotide Repeats; Phenotype; Point Mutation; Polymerase Chain Reaction; Population; Purpose; Range; Research; Schizophrenia; Screening procedure; Southern Blotting; Untranslated RNA; base; case control; interest; nervous system disorder; research study

DESCRIPTION (provided by applicant): Schizophrenia is a severe, debilitating psychiatric disorder of unknown cause. I hypothesize that some cases of schizophrenia are caused by individually rare, often de novo, highly penetrant mutations. Sporadic cases of schizophrenia occurring in previously unaffected families may be most likely to harbor such mutations. Potentially unstable oligonucleotide repeats are among genomic features most vulnerable to such mutations. Repeat expansions are potentially intriguing in schizophrenia given the disorder's neurological phenotype, paternal age bias, and possible anticipation. The purpose of this project is to identify pathogenic repeat expansions with large effect on the development of schizophrenia. Using a bioinformatics search, I have identified 327 tri-, tetra-, or pentanucleotide repeats that overlap transcribed features (i.e. coding genes or noncoding RNAs) and are sufficiently long to likely be polymorphic. By screening genomic DNA from individuals with sporadic schizophrenia, I will identify repeats with more apparent homozygotes than expected based on Hardy-Weinberg equilibrium (HWE) criteria. To exclude loss of heterozygosity due to technical artifacts, I will genotype repeats that fail HWE, using multiple primer pairs, in cases and ancestry-matched controls. In preliminary experiments, I have identified a repeat with a two-fold excess of homozygosity among cases but perfect fit to HWE among controls. This excess is observed with multiple non-overlapping primer pairs and after identifying short repeats by capillary electrophoresis and medium length repeats by long-range PCR. Next I will screen cases and controls at this locus by Southern blot to identify any expansions >300 repeats and any deletions of the entire repeat. I will evaluate repeats elsewhere in the genome in the same way. If either large expansions or deletions are observed at any repeat, I will undertake preliminary experimental characterization of the mutations. I will also sequence genes harboring interesting repeats in all cases to identify mutations other than repeat expansions; e.g. frameshifts or point mutations. The goal of NIMH is to reduce the burden of mental illness through research. This study aims to identify genetic contributors to schizophrenia, which will hopefully lead to better diagnostic testing and treatment for individuals with the disorder.

描述（由申请人提供）：精神分裂症是一种原因不明的严重、使人衰弱的精神疾病。我假设一些精神分裂症病例是由个别罕见的，通常是从头开始的，高度渗透的突变引起的。在以前未受影响的家庭中发生的零星精神分裂症病例可能最有可能携带这种突变。潜在不稳定的寡核苷酸重复序列是最易受这种突变影响的基因组特征之一。考虑到精神分裂症的神经表型、父亲的年龄偏见和可能的预期，重复扩张在精神分裂症中可能是有趣的。本项目的目的是鉴定对精神分裂症发展有重大影响的致病性重复扩增。使用生物信息学搜索，我已经确定了327个重叠转录特征（即编码基因或非编码rna）的三、四或五核苷酸重复序列，并且足够长，可能是多态性的。通过筛选散发性精神分裂症患者的基因组DNA，我将根据Hardy-Weinberg平衡（HWE）标准，识别出具有比预期更多明显纯合子的重复序列。为了排除由于技术人为因素导致的杂合性损失，我将使用多个引物对，在病例和祖先匹配的对照中，对HWE失败的重复序列进行基因分型。在初步实验中，我已经确定了一个重复，在病例中纯合性超过两倍，但在对照组中完全符合HWE。这种过剩是通过多个不重叠的引物对观察到的，并且通过毛细管电泳鉴定了短重复序列，通过远程PCR鉴定了中长度重复序列。接下来，我将通过Southern blot对该位点的病例和对照进行筛选，以确定是否有扩增到300个重复序列和整个重复序列的缺失。我将以同样的方式评估基因组中其他地方的重复序列。如果在任何重复中观察到大量扩增或缺失，我将对突变进行初步的实验表征。我还将对所有情况下具有有趣重复序列的基因进行测序，以识别除重复扩增外的突变；例如，帧移或点突变。NIMH的目标是通过研究来减轻精神疾病的负担。这项研究旨在确定精神分裂症的遗传因素，这有望为患有这种疾病的个体提供更好的诊断测试和治疗。