Identification and Characterization of Genes in Congenital Diaphragmatic Hernia

描述(由申请人提供)：这项提案的目标是识别和表征先天性横隔疝(CDH)的新基因。CDH发生率为1/3000，死亡率为30-60%，主要由肺发育不良和肺动脉高压引起。30%-40%的CDH病例与其他严重的出生缺陷有关，包括心脏异常。虽然遗传因素在横隔膜发育中起着重要的作用，但目前仅有少数CDH基因被鉴定出来，并且对它们引起CDH的机制知之甚少。本研究的具体目的是：1)定位和鉴定与人类CDH相关的基因；2)确定Sox7小鼠模型中导致前部CDH发生的组织病理学机制；3)确定Sox7与Gata4在前部CDH发生中是否存在相互作用。阵列比较基因组杂交(ACGH)已被证明是识别CDH等散发性疾病基因的一种有效的、无偏见的方法。来自150名CDH患者的DNA将使用定制的专注于外显子的aCGH阵列进行CDH相关的小染色体缺失/复制筛查。候选基因将从这些区域中挑选出来，并在我们的CDH队列中筛选额外的突变。然后，将根据个别患者的临床信息进行基因-表型相关性。ACGH研究表明，CDH中最常见的缺失染色体区域之一是8p23.1的一部分，该区域含有S0X7基因。我们将使用新建立的Sox7小鼠CDH模型来探索前部CDH形成的组织病理学机制。研究将寻找可能损害横隔膜结构完整性的变化，以及将横隔膜与肝脏分开的腹膜间皮折叠异常扩张的证据。这些机制很可能与导致人类前部CDH的机制相似。SOX7是Gata4上调所必需的，Gata4是位于8p23.1上CDH关键区的另一个CDH相关基因。体内的小鼠研究将被用来确定Sox7和Gata4在前横隔膜发育过程中是否存在遗传上的相互作用，随后将进行体外研究，以确定这种相互作用的分子基础。这些研究将有助于确定导致一些儿童患上先天性横隔疝(CDH)的基因变化，CDH是一种威胁生命的出生缺陷。所获得的知识将帮助医生为受影响的家庭提供更好的医疗保健和遗传咨询，并可能导致预防或治疗这些疝气的新方法。由于30%-40%的CDH儿童有其他严重的出生缺陷，这些研究也可能帮助医生和科学家了解这些缺陷的原因以及如何治疗它们。

DESCRIPTION (provided by applicant): The goal of this proposal is to identify and characterize novel genes for congenital diaphragmatic hernia (CDH). CDH occurs in ~1/3000 live births and has a mortality rate of 30-60% caused mostly by pulmonary hypoplasia and pulmonary hypertension. 30-40% of CDH cases are associated with other severe birth defects including heart anomalies. Although genetic factors clearly play an important role in diaphragm development only a few CDH genes have been identified and little is known about the mechanisms by which they cause CDH. The Specific Aims for this study are: 1) map and identify genes that contribute to human CDH, 2) determine the histopathologic mechanisms that lead to development of anterior CDH in the Sox7 mouse model, and 3) determine if Sox7 interacts with Gata4 in development of anterior CDH. Array comparative genomic hybridization (aCGH) has been shown to be an effective non-biased method for identifying genes in sporadic disorders like CDH. DNA from a cohort of 150 CDH patients will be screened for small CDH-related chromosomal deletions/duplications using a custom designed exon-focused aCGH array. Candidate genes will be selected from these regions and screened for additional mutations in our CDH cohort. Genotype-phenotype correlations will then be made based on clinical information from individual patients. aCGH studies have revealed that one of the most common chromosomal regions deleted in CDH is a portion of 8p23.1 which contains the S0X7 gene. A newly-created Sox7 mouse model of CDH will be used to explore the histopathologic mechanisms that underlie the formation of anterior CDH. Studies will look for changes that could compromise the structural integrity of the diaphragm and evidence of abnormal expansion of the peritoneal mesothelial folds that separate the diaphragm from the liver. It is likely that these mechanisms will be similar to those which cause anterior CDH in humans. Sox7 is required for upregulation of Gata4, another CDH-related gene located in the CDH critical region on 8p23.1. In vivo mouse studies will be used to determine if Sox7 and Gata4 interact genetically in anterior diaphragm development followed by in vitro studies to determine the molecular basis of this interaction. These studies will help identify genetic changes that cause some children to develop congenital diaphragmatic hernia (CDH), a life threatening birth defect. The knowledge gained will help doctors provide better medical care and genetic counseling to affected families and may lead to new ways to prevent or treat these hernias. Since 30-40% of all children with CDH have other severe birth defects, these studies may also help physicians and scientists understand what causes these defects and how to treat them.