Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, USA.
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Genet Med. 2021 Oct;23(10):1912-1921. doi: 10.1038/s41436-021-01222-w. Epub 2021 Jun 10.
In this study, we aimed to characterize the clinical phenotype of a SHANK1-related disorder and define the functional consequences of SHANK1 truncating variants.
Exome sequencing (ES) was performed for six individuals who presented with neurodevelopmental disorders. Individuals were ascertained with the use of GeneMatcher and Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources (DECIPHER). We evaluated potential nonsense-mediated decay (NMD) of two variants by making knock-in cell lines of endogenous truncated SHANK1, and expressed the truncated SHANK1 complementary DNA (cDNA) in HEK293 cells and cultured hippocampal neurons to examine the proteins.
ES detected de novo truncating variants in SHANK1 in six individuals. Evaluation of NMD resulted in stable transcripts, and the truncated SHANK1 completely lost binding with Homer1, a linker protein that binds to the C-terminus of SHANK1. These variants may disrupt protein-protein networks in dendritic spines. Dispersed localization of the truncated SHANK1 variants within the spine and dendritic shaft was also observed when expressed in neurons, indicating impaired synaptic localization of truncated SHANK1.
This report expands the clinical spectrum of individuals with truncating SHANK1 variants and describes the impact these variants may have on the pathophysiology of neurodevelopmental disorders.
本研究旨在描述 SHANK1 相关疾病的临床表型，并确定 SHANK1 截断变异的功能后果。
对 6 名具有神经发育障碍的个体进行外显子组测序 (ES)。使用 GeneMatcher 和利用 Ensembl 资源的人类染色体不平衡和表型数据库 (DECIPHER) 来确定个体。我们通过制作内源性截断 SHANK1 的敲入细胞系，评估了两种变异的潜在无义介导的衰变 (NMD)，并在 HEK293 细胞和培养的海马神经元中表达截断 SHANK1 cDNA，以检查蛋白质。
ES 在 6 名个体中检测到 SHANK1 的新生截断变异。NMD 的评估导致稳定的转录本，并且截断的 SHANK1 完全失去与 Homer1 的结合，Homer1 是一种与 SHANK1 的 C 末端结合的连接蛋白。这些变异可能会破坏树突棘中的蛋白-蛋白网络。当在神经元中表达时，也观察到截断 SHANK1 变体在棘突和树突干内分散定位，表明截断 SHANK1 的突触定位受损。
本报告扩展了具有截断 SHANK1 变异个体的临床谱，并描述了这些变异可能对神经发育障碍病理生理学的影响。
