Genomic and functional characterization of ASD and ID-associated MYT1L mutation

人类遗传学的最新进展已经定义了数百种自闭症的因果变异 谱系障碍（ASD）和其他智力和发育障碍（IDDs）。然而，在这方面， 需要大量的努力来确定下游疾病过程，从而指导 为每个人制定干预措施。一个这样的新ASD基因是MYT 1 L-而突变 最近发现MYT 1 L与人类ASD和智力残疾（IDD）有关， MYT 1 L在神经细胞和神经回路中的作用尚不清楚。因此，在这里，我们提出一个全面的 MYT 1 L的机制研究该项目使用了两个尖端的既定工作流程 以及创新的新方法，使深入研究MYT 1 L损失的分子， 细胞、结构和行为电路水平。我们将利用两个互补的实验 系统、小鼠模型和人诱导多能干细胞（iPSC）衍生的神经元， 确定MYT 1 L的正常作用，并确定MYT 1 L丢失的后果和可逆性。 我们首先关注在MYT 1 L假定功能丧失患者中鉴定的突变， 除了将该变体敲入同基因对照PSC系之外， 我们从这个受试者中获得了iPSC模型，有和没有MYT 1 L变体校正， 我们确定MYT 1 L突变在人类遗传背景中的一致后果。 我们还开发了靶向旁系同源氨基酸的小鼠模型，以使研究成为可能。 MYT 1 L缺失对大脑结构、生理和行为回路功能的影响。 此外，为小鼠和人类模型开发的尖端基因治疗工具将 使我们能够研究拯救基因功能的效果。类似的里程碑式实验 深刻地改变了对其他神经发育障碍的理解， 很大一部分表型是可逆的，从而刺激了 基于拯救基因表达的治疗方法。总之，这里进行的实验将 阐明MYT 1 L控制大脑发育的要求和机制， 功能，将决定这些功能如何被致病性MYT 1 L突变破坏，并且还可能 制定MYT 1 L靶向治疗的路线。

Recent advances in human genetics have defined hundreds of causal variants for Autism Spectrum Disorder (ASD) and other intellectual and developmental disabilities (IDDs). However, substantial effort is required to define downstream disease processes and thus to guide development of interventions for each one. One such new ASD gene is MYT1L – while mutations in MYT1L have recently become associated with ASD and Intellectual Disability (IDD) in humans, the role of MYT1L in neural cells and circuits is unclear. Thus, here, we propose a comprehensive mechanistic investigation of MYT1L. This project uses both cutting-edge established workflows as well as innovative new approaches to enable in-depth study of MYT1L loss at the molecular, cellular, structural, and behavioral circuit levels. We will utilize two complementary experimental systems, mouse models and human induced pluripotent stem cell (iPSC)-derived neurons, to define MYT1L's normal roles, and to identify the consequences and reversibility of MYT1L loss. We focus initially on a mutation identified in a patient with a MYT1L putative loss-of-function variant who has ASD and ID. In addition to knock-in of this variant into isogenic control PSC lines, we derived iPSC models from this subject, with and without MYT1L variant correction, enabling us to define consistent consequences of MYT1L mutation across human genetic backgrounds. We also developed mouse models targeting the paralogous amino acid, to enable studies of the consequence of MYT1L loss on brain structure, physiology, and behavioral circuit function. Further, cutting-edge gene therapy-like tools developed for both mouse and human models will allow us to investigate the effects of rescuing gene function. Similar landmark experiments profoundly changed the understanding of other neurodevelopmental disorders by demonstrating that a substantial proportion of the phenotype was reversible, thus spurring the development of therapeutics based on rescuing gene expression. Together, the experiments performed here will elucidate the requirements for and mechanisms by which MYT1L controls brain development and function, will determine how these are disrupted by pathogenic MYT1L mutation, and could also chart a course towards MYT1L-targeted therapies.