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: 7332528
• 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/7332528
• 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）：精神分裂症是一种严重的，使人衰弱的精神疾病的原因不明。我推测，一些精神分裂症病例是由个体罕见的，往往是从头，高度渗透突变。在以前未受影响的家庭中发生的精神分裂症的零星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此类突变影响的基因组特征之一。考虑到精神分裂症的神经学表型、父亲年龄偏差和可能的预期，重复扩增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的发展有很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327三，四，或五核苷酸重复重叠转录功能（即编码基因或非编码RNA），并足够长，可能是多态性。通过筛选散发性精神分裂症个体的基因组DNA，我将根据Hardy-Weinberg平衡（HWE）标准确定具有比预期更明显纯合子的重复序列。为了排除由于技术因素造成的杂合性丢失，我将在病例和祖先匹配的对照中使用多个引物对HWE失败的重复进行基因分型。在初步的实验中，我已经确定了一个重复与两倍过量的纯合性的情况下，但完美的适合HWE之间的控制。用多个非重叠引物对并且在通过毛细管电泳鉴定短重复序列和通过长距离PCR鉴定中等长度重复序列之后观察到这种过量。接下来，我将通过Southern印迹在该位点筛选病例和对照，以鉴定任何>300个重复的扩增和整个重复的任何缺失。我将以同样的方式评估基因组中其他地方的重复序列。如果在任何重复序列中观察到大的扩增或缺失，我将对突变进行初步的实验表征。我还将测序在所有情况下含有感兴趣的重复序列的基因，以识别除重复扩增以外的突变;例如，移码或点突变。NIMH的目标是通过研究减轻精神疾病的负担。这项研究的目的是确定精神分裂症的遗传因素，这将有望导致更好的诊断测试和治疗患有这种疾病的个人。