Identification and Characterization of Genes in Congenital Diaphragmatic Hernia

描述（由申请人提供）：本提案的目的是鉴定和表征先天性膈疝（CDH）的新基因。CDH发生在约1/3000活产婴儿中，死亡率为30-60%，主要由肺发育不全和肺动脉高压引起。30-40%的CDH病例伴有其他严重出生缺陷，包括心脏异常。虽然遗传因素在横膈膜发育中起着重要的作用，但只有少数CDH基因被确定，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)绘制和鉴定导致人类CDH的基因；2)确定Sox7小鼠模型中导致前路CDH发展的组织病理学机制；3)确定Sox7在前路CDH发展中是否与Gata4相互作用。阵列比较基因组杂交（Array comparative genomic hybridization, aCGH）已被证明是一种有效的、无偏倚的方法来鉴定散发性疾病（如CDH）的基因。来自150名CDH患者的DNA将使用定制设计的外显子聚焦aCGH阵列筛选CDH相关的小染色体缺失/重复。候选基因将从这些区域中选择，并在我们的CDH队列中筛选其他突变。基因型-表现型的相关性将基于个体患者的临床信息。aCGH研究表明，CDH中最常见的染色体区域之一是8p23.1中包含S0X7基因的部分。新创建的Sox7小鼠CDH模型将用于探索前路CDH形成的组织病理学机制。研究将寻找可能损害横膈膜结构完整性的变化，以及横膈膜与肝脏分离的腹膜间皮褶皱异常扩张的证据。这些机制很可能与导致人类前侧CDH的机制相似。Sox7是上调另一个CDH相关基因Gata4所必需的，Gata4位于8p23.1上的CDH关键区域。小鼠体内研究将用于确定Sox7和Gata4是否在前膈发育中遗传相互作用，然后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膈疝（CDH）的基因变化，这是一种危及生命的出生缺陷。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患儿有其他严重的出生缺陷，这些研究也可以帮助医生和科学家了解导致这些缺陷的原因以及如何治疗这些缺陷。

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.