The genetic basis of Dandy-Walker and other mid-hindbrain malformations

 描述(申请人提供)：我们这个项目的长期目标是促进我们对脑干和小脑的发育障碍的理解，这是源于胚胎中脑和后脑的大脑结构，我们统称为中后脑畸形(MHM)。这些疾病至少影响每6-7000名活产儿中的1人，而且可能更多，因为这些数字没有考虑到与早产或自闭症相关的小脑异常。此外，众所周知，小脑畸形与几种更常见的发育障碍并存，包括自闭症、智力低下和某些类型的早期癫痫。随着这一更新，我们建议继续使用我们的大量且不断增长的患有MHM的人类受试者来定义这些发育障碍的基因、途径和生物学机制。我们将使用最新的基因组技术-靶向基因面板大规模并行(NextGen)测序、全外显子组测序(WXS)或全基因组测序(WGS)-与较旧的方法相结合，找出罕见和常见MHM的原因。在目标1中，我们将继续寻找导致MHM的罕见单基因原因的基因，这些基因将展示最重要的分子途径，包括导致更常见疾病(如自闭症)的途径。例如，我们已经在一名患有MHM的儿童中发现了第一个AUTS2基因的错义突变(以前与自闭症有关)。在目标2中，我们将转向更具挑战性但也更重要的Dandy-Walker畸形问题，这是人类最常见的MHM。这种特殊的畸形表现出很大的因果异质性，事实证明，用旧技术很难解决这一问题，这使得整个外显子组和基因组测序方法至关重要。目标1-2需要通过正在进行的受试者招募来支持，因为对智力低下和自闭症等类似障碍的研究已经受益于大量的受试者。在目标3中，我们建议使用新的CRISPR/Cas技术来测试AIMS 1-2中确定的基因和网络的生物学功能，以有效地生成新的已证实的和强候选MHM相关基因的小鼠模型。例如，我们现在正在生成AUTS2的第一个鼠标模型。我们预计，这些研究将迅速为更准确的诊断和咨询做出贡献，随着时间的推移，将导致针对这些疾病的子集开发特定的治疗方法。我们预测，对中后脑发育的研究将对人类发育障碍具有广泛的意义，为小脑发育与其他类型的发育障碍之间的联系提供了令人信服的证据。

 DESCRIPTION (provided by applicant): Our long-term goal for this project is to advance our understanding of developmental disorders of the brainstem and cerebellum, brain structures derived from the embryonic midbrain and hindbrain, which we refer to collectively as mid-hindbrain malformations (MHM). These disorders affect a minimum of 1 per 6-7000 live births, and likely far more as these numbers do not account for cerebellar abnormalities associated with preterm birth or with autism. Further, cerebellar malformations are known to co-occur with several more common developmental disorders including autism, mental retardation and some types of early life epilepsy. With this renewal, we propose to continue using our large and growing cohort of human subjects with MHM to define the genes, pathways and biological mechanisms underlying these developmental disorders. We will use the most recent genomic technology - massively parallel (NextGen) sequencing of targeted gene panels, whole exome sequencing (WXS) or whole genome sequencing (WGS) - combined with older methods to find the causes of both rare and common MHM. In Aim 1, we will continue to search for genes underlying rare single gene causes of MHM that will demonstrate the most important molecular pathways, including pathways that contribute to more common disorders such as autism. As an example, we have identified the first missense mutation of the AUTS2 gene (previously linked to autism) in a child with MHM. In Aim 2, we will turn to the more challenging but also more important problem of Dandy-Walker malformation, the most common MHM in humans. This specific malformation demonstrates substantial causal heterogeneity and has proven difficult to solve with older technologies, making whole exome and genome sequencing approaches essential. Aims 1-2 need to be supported by ongoing subject recruitment, as studies of comparable disorders such as mental retardation and autism have benefited from large numbers of subjects. In Aim 3, we propose to test the biological function of genes and networks identified in Aims 1-2 using new CRISPR/Cas technology to efficiently generate new mouse models of proven and strong candidate MHM-associated genes. For example, we are now generating the first mouse models of Auts2. We expect that these studies will contribute rapidly to more accurate diagnosis and counseling, and over time will lead to development of specific treatments for a subset of these disorders. We predict that studies of mid-hindbrain development will have broad significance for human developmental disorders generally, providing compelling evidence for a connection between cerebellar development and other classes of developmental disorders.