Functional characterization of rare NRXN1 variants identified in autism spectrum disorders and schizophrenia
Functional characterization of rare NRXN1 variants identified in autism spectrum disorders and schizophrenia
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DOI：
10.1186/s11689-020-09325-2
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发表时间：
2020-09-17
影响因子：
4.9
通讯作者：
Ozaki, Norio
中科院分区：
文献类型：
--
作者：
Ishizuka, Kanako;Yoshida, Tomoyuki;Ozaki, Norio
背景：罕见的遗传变异有助于自闭症谱系障碍（ASD）和精神分裂症（SCZ）的病因。大多数遗传学研究将重点限制在可能的基因破坏突变上，因为它们相对更容易解释它们对基因产物的影响。错义变体的解释也为这些神经发育障碍的一些病理生理机制提供了信息;然而，由于相对较小的影响，它们的贡献尚未得到阐明。因此，我们从ASD和SCZ患者中检测到NRXN 1（一种众所周知的神经发育疾病致病基因）的错义变体。方法：为了发现具有大效应量的罕见变异并评估其在ASD和SCZ的共同病因病理生理学中的作用，我们对包括562名日本ASD和SCZ患者的样本的NRXN 1编码外显子进行测序，然后对4273个无关个体进行遗传关联分析。使用体外功能测定和计算机三维（3D）结构建模分析了此处检测到的每个错义变体对细胞表面表达、与NLGN 1的相互作用和突触发生活性的影响。通过突变筛选，我们认为三个超罕见的错义突变体，（T737 M，D 772 G和R856 W），所有这些都影响NRXN 1 α亚型的LNS 4结构域，作为疾病相关变体。T737 M、D 772 G和R856 W个体的诊断分别为1例ASD和1例SCZ，1例ASD和1例SCZ。我们观察到由每个变体引起的以下表型和功能负担。(i)D 772 G和R856 W携带者的社会功能障碍比T737 M携带者严重。(ii)体外试验显示，D 772 G和R856 W突变降低了NRXN 1 α的细胞表面表达。体外功能分析显示T737 M和D 772 G突变体的NRXN 1 α-NLGN 1相互作用降低。(iii)计算机三维结构建模表明，T737 M和D 772 G突变可以不稳定的杆状结构的LNS 2-LNS 5域，和D 772 G和R856 W可以干扰N-聚糖构象的运输signal.Conclusions：合并的数据表明，在NRXN 1的错义变体可能与表型的神经发育障碍以外的ASD和/或SCZ的诊断。
Background: Rare genetic variants contribute to the etiology of both autism spectrum disorder (ASD) and schizophrenia (SCZ). Most genetic studies limit their focus to likely gene-disrupting mutations because they are relatively easier to interpret their effects on the gene product. Interpretation of missense variants is also informative to some pathophysiological mechanisms of these neurodevelopmental disorders; however, their contribution has not been elucidated because of relatively small effects. Therefore, we characterized missense variants detected in NRXN1, a well-known neurodevelopmental disease-causing gene, from individuals with ASD and SCZ.Methods: To discover rare variants with large effect size and to evaluate their role in the shared etiopathophysiology of ASD and SCZ, we sequenced NRXN1 coding exons with a sample comprising 562 Japanese ASD and SCZ patients, followed by a genetic association analysis in 4273 unrelated individuals. Impact of each missense variant detected here on cell surface expression, interaction with NLGN1, and synaptogenic activity was analyzed using an in vitro functional assay and in silico three-dimensional (3D) structural modeling.Results: Through mutation screening, we regarded three ultra-rare missense variants (T737M, D772G, and R856W), all of which affected the LNS4 domain ofNRXN1 alpha isoform,as disease-associated variants. Diagnosis of individuals with T737M, D772G, and R856W was 1ASD and 1SCZ, 1ASD, and 1SCZ, respectively. We observed the following phenotypic and functional burden caused by each variant. (i) D772G and R856W carriers had more serious social disabilities than T737M carriers. (ii) In vitro assay showed reduced cell surface expression of NRXN1 alpha by D772G and R856W mutations. In vitro functional analysis showed decreased NRXN1 alpha-NLGN1 interaction of T737M and D772G mutants. (iii) In silico 3D structural modeling indicated that T737M and D772G mutations could destabilize the rod-shaped structure of LNS2-LNS5 domains, and D772G and R856W could disturb N-glycan conformations for the transport signal.Conclusions: The combined data suggest that missense variants in NRXN1 could be associated with phenotypes of neurodevelopmental disorders beyond the diagnosis of ASD and/or SCZ.