SHANK3基因缺失/点突变与孤独症表型关系的研究及机制探讨

Autism spectrum disorder (ASD) is a major public health problem affecting 1 out 110 children. Understanding these mechanisms is critical for developing novel therapeutic approaches. The limitations inherent in human studies make it difficult to study cellular and molecular mechanisms, providing a rationale for the study of animal models. Recent genetic evidence implicates the SHANK3 gene in ASD. Deletion of the SHANK3 gene is a major contributor to ASD features in the 22q13.3 deletion syndrome. Microdeletions of the entire SHANK3 gene and point mutations of SHANK3 disrupting specific isoforms have been identified in patients with ASD and intellectual disability. The reported Shank3 isoform-knockout mice have different exonic deletions, showing notable phenotypic differences. This phenotypic heterogeneity could be explained by the different impact that each mutation has on isoform-specific expression of Shank3. However, due to the difference of the SHANK3 gene mutation and clinical manifestations very different, it is difficult to establish a link between the genotype and phenotype, also can not clear the specific role of the mechanism. In this project, we will detect 500 clinical diagnostic AD cases using MLPA and PCR sequencing to analysis the SHANK3 gene mutation patterns, in combined with literature reports,we will summary the genotype and phenotype pattern of SHANK3. Then, using different mouse knockout model and builted zebrafish knockout model,we will analysis the behavior of animal model, the morphology of the brain tissue and the changes of related molecular to verify the autism like phenotype and further explore the mechanism. The aim of our study is to get the intrinsic relationship between the SHANK3 genotype and phenotype, and to explain the molecular mechanism of autism like behavioral of SHANK3 gene mutations.The knowledge gained from this study will provide new insights that may be contribute to the intervention of the autism.

孤独症已成为逐渐被公众所认识的一种严重影响青少年情感和智力发育的疾病，其发病机制复杂。既往在孤独症人群中发现SHANK3基因突变，提示SHANK3在孤独症的发生中具有重要作用。但是，由于SHANK3基因的不同点突变和不同缺失片段的临床表现差异很大，难以建立基因型与表型之间的联系，亦无法明确其具体作用机制。本课题拟通过对500例临床诊断为孤独症的患儿进行MLPA检测和PCR测序，分析SHANK3在孤独症患儿中基因缺失、点突变的分布情况，结合已报道突变类型，分析不同突变之间的临床表型谱及差异。然后，采用不同的小鼠基因敲除模型和根据突变谱构建斑马鱼模型，通过模式动物的行为学分析，大脑组织结构形态学和分子水平检测，进行进一步的机制探讨。目的是获得SHANK3基因型与表型之间的内在关系，解释SHANK3基因突变导致孤独症发生的形态、行为变化的分子机制，为孤独症的分子靶向干预提供新的思路。

.孤独症谱系障碍（ASD）是一类复杂的神经发育性疾病，发病率高，严重影响青少年社交/情感及智力发育及其家庭的生活质量，其发病机制复杂，遗传因素起着重要作用。现有证据表明，SHANK3基因的缺陷与ASD之间具有强烈的因果关系。但由于SHANK3的不同点突变和不同缺失片段的临床表现差异很大，难以建立基因型与表型之间的联系，亦无法明确其具体作用机制。本课题通过对510例临床诊断为ASD的患儿进行MLPA检测和PCR测序，检测出2例阳性样本（0.4%），另外在门诊中又收集到12例阳性患儿，共14例。其中12例是SHANK3杂合性缺失，2例是点突变。其共同特征是全面发育迟缓、肌张力重度低下、语言能力重度缺陷和孤独症样特征。和姜永辉教授课题组合作，成功构建了Shank3敲除的小鼠模型，行为学检测表现出典型的孤独症样的行为；我们课题组自主构建了国际上第一个shank3敲除的斑马鱼模型，行为表现为游动速度降低、社交偏好性减少、刻板性游动显著增加等特征。大脑突触相关蛋白水平检测显示突触前和突触后的重要蛋白含量均降低，提示shank3在突触功能中具有非常重要的作用，为进一步药物筛选和孤独症的分子及药物靶向干预提供新的思路。.