Technologies for Mapping Interspersed AGG Sequences in the FMR1 Gene

描述（由申请人提供）：本项目的总体目标是验证、商业化并进一步建立一套全面的基因分型检测的临床实用性，以改善脆性X综合征（FXS）相关疾病的筛查和诊断。CGG重复序列中散布的AGG序列测试的相关性已经从脆性X智力低下（FMR 1）基因扩增的人群研究中提出。已经提出重复CGG元件内AGG重复的数量和序列背景赋予世代扩展稳定性。尽管AGG散布与三联体重复扩增的风险相关，但这些散布以前无法在大多数女性样本中确定。我们建议完善中间和前突变等位基因的风险估计，将AGG散置信息到档案DNA样本的FMR 1等位基因传输的分析，使用确定的AGG映射分析，我们已经开发。我们的检测方法利用高通量PCR，并承诺改进诊断和风险评估，以实现准确的AGG基因分型，并明确确定每个样本等位基因的连续CGG重复序列的数量。我们达到或超过了第一阶段赠款的所有拟议目标。这一成功导致了具有全面AGG基因分型能力的FMR 1的互补分子遗传测定。我们的学术合作者参与了大型临床试验，这些试验将检查对FMR 1重复扩增重要的遗传因素，我们的技术将成为评估一系列FMR 1疾病的散布AGG映射的临床实用性的核心。第二阶段的目标是：目标1：将I期开发的检测技术应用于回顾性临床样本，以更精确地定义CGG重复扩增中AGG基因分型的临床效用。目标二：开发一套用于检测AGG重复序列的质控品和标准品，并将试剂、质控品和QC指标整合到一个全面的工作流程中，支持基于PCR的AGG基因型检测。目标3：开发和测试便于用户使用的软件组件，用于绘制AGG位置。目标4：整合和评估目标2和3中开发的综合测试功能。 公共卫生相关性：我们正在开发一种快速，具有成本效益的分子测试，以检测与脆性X综合征相关的基因突变。脆性X染色体是最常见的遗传性精神发育迟滞形式之一，也可能导致其他疾病和病症，如多动症和自闭症。预计诊断测试将识别出那些有很高风险将这种疾病传给孩子的人。

DESCRIPTION (provided by applicant): The overall objective for this project is to validate, commercialize, and further establish the clinical utility of a comprehensive set of genotyping assays to improve screening and diagnosis of conditions associated with fragile X syndrome (FXS). The relevance of testing for interspersed AGG sequences in CGG repeats has been proposed from population studies of fragile X mental retardation (FMR1) gene expansion. Both the number and sequence context of AGG repeats within the repeat CGG element have been proposed to confer stability to generational expansion. Although AGG interspersions are associated with the risk of triplet repeat expansion, these interspersions previously could not be determined in most female samples. We propose to refine the risk estimates for intermediate and premutation alleles by incorporating AGG interspersion information into the analysis of FMR1 allele transmissions from archived DNA samples using the definitive AGG mapping assays that we have developed. Our assay approach, leverages high throughput PCR and promises improved diagnostic and risk assessments for enabling accurate AGG genotyping, and definitive determination of the number of consecutive CGG repeats for each sample allele. We met or exceeded all proposed aims in the phase I grant. This success has resulted in complementary molecular genetic assays for FMR1 with comprehensive AGG genotyping capabilities. Our academic collaborators are involved in large clinical trials that will examine the genetic factors important for FMR1 repeat expansions, and our technology will be the centerpiece to evaluate the clinical utility of the interspersed AGG mapping for a range of FMR1 disorders. The aims for phase II are: Aim 1: Apply the assay technologies developed in Phase I to retrospective clinical samples to more precisely define the clinical utility of AGG genotyping in CGG repeat expansions. Aim 2: Develop a set of controls and standards for detection of AGG repeats and integrate reagents, controls and QC metrics into a comprehensive workflow that supports the PCR-based detection of AGG genotypes. Aim 3: Develop and test user-friendly software components for mapping AGG positions. Aim 4: Integrate and evaluate comprehensive test features developed in Aims 2 and 3. PUBLIC HEALTH RELEVANCE: We are developing a rapid, and cost-effective molecular test to detect genetic mutation associated with Fragile X Syndrome. Fragile X is one of the most commonly inherited forms of mental retardation and can also cause other disorders and conditions such as ADHD and autism. The diagnostic test is expected to identify people who have a high risk of passing the disorder onto their children.