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

 描述（由申请人提供）：本项目的长期目标是促进我们对脑干和小脑发育障碍的理解，这些发育障碍是源自胚胎中脑和后脑的脑结构，我们将其统称为中脑-后脑畸形（MHM）。这些疾病影响每6-7000活产婴儿中至少1例，并且可能更多，因为这些数字不考虑与早产或自闭症相关的小脑异常。此外，已知小脑畸形与几种更常见的发育障碍共同发生，包括自闭症，精神发育迟滞和某些类型的早期癫痫。通过这次更新，我们建议继续使用我们庞大且不断增长的MHM人类受试者队列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-靶向基因组的大规模平行（NextGen）测序，全外显子组测序（WXS）或全基因组测序（WGS）-结合旧方法来寻找罕见和常见MHM的原因。在目标1中，我们将继续寻找MHM的罕见单基因原因的基因，这些基因将证明最重要的分子途径，包括导致更常见疾病（如自闭症）的途径。作为一个例子，我们已经确定了第一个错义突变的AUTS 2基因（以前与自闭症）在儿童MHM。在目标2中，我们将转向更具挑战性但也更重要的问题Dandy-Walker畸形，人类最常见的MHM。这种特定的畸形表现出实质性的因果异质性，并且已被证明难以用旧技术解决，使得全外显子组和基因组测序方法至关重要。目标1-2需要通过持续的受试者招募来支持，因为对精神发育迟滞和自闭症等类似疾病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技术来测试目标1-2中鉴定的基因和网络的生物学功能，以有效地生成经验证的强候选MHM相关基因的新小鼠模型。例如，我们现在正在生成Auts 2的第一个小鼠模型。我们希望这些研究将有助于更准确的诊断和咨询，并随着时间的推移将导致这些疾病的一个子集的特定治疗的发展。我们预测，中后脑发育的研究将对人类发育障碍具有广泛的意义，为小脑发育和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.