Abstract：
Walker-Warburg syndrome (WWS) is a genetically heterogeneous disease that often presents with complex brain and eye malformations and congenital muscular dystrophy. Mutations of the ISPD gene have been identified as one of the most frequent causes of WWS.
The current study aimed to identify the cause of severe congenital hydrocephalus and brain dysplasia in our subject.
Genomic DNA was extracted from the fetus\'s umbilical cord blood and peripheral venous blood of the parents. The genetic analysis included whole-exome sequencing and qPCR. Additionally, in silico analysis and cellular experiments were performed.
We identified a novel homozygous deletion of exons 7 to 9 in the ISPD gene of the fetus with WWS. In silico analysis revealed a defective domain structure in the C-terminus domain of the ISPD. Analysis of the electrostatic potential energy showed the formation of a new binding pocket formation on the surface of the mutant ISPD gene (ISPD-del ex7-9). Cellular study of the mutant ISPD revealed a significant change in its cellular localization, with the ISPD-del ex7-9 protein translocating from the cytoplasm to the nucleus compared to wild-type ISPD, which is mostly present in the cytoplasm.
The present study expands the mutational spectrum of WWS caused by ISPD mutations. Importantly, our work suggests that whole-exome sequencing could be considered as a diagnostic option for fetuses with congenital hydrocephalus and brain malformations when karyotype or chromosomal microarray analysis fails to provide a definitive diagnosis.
The current study aimed to identify the cause of severe congenital hydrocephalus and brain dysplasia in our subject.
Genomic DNA was extracted from the fetus\'s umbilical cord blood and peripheral venous blood of the parents. The genetic analysis included whole-exome sequencing and qPCR. Additionally, in silico analysis and cellular experiments were performed.
We identified a novel homozygous deletion of exons 7 to 9 in the ISPD gene of the fetus with WWS. In silico analysis revealed a defective domain structure in the C-terminus domain of the ISPD. Analysis of the electrostatic potential energy showed the formation of a new binding pocket formation on the surface of the mutant ISPD gene (ISPD-del ex7-9). Cellular study of the mutant ISPD revealed a significant change in its cellular localization, with the ISPD-del ex7-9 protein translocating from the cytoplasm to the nucleus compared to wild-type ISPD, which is mostly present in the cytoplasm.
The present study expands the mutational spectrum of WWS caused by ISPD mutations. Importantly, our work suggests that whole-exome sequencing could be considered as a diagnostic option for fetuses with congenital hydrocephalus and brain malformations when karyotype or chromosomal microarray analysis fails to provide a definitive diagnosis.
摘要：
背景：Walker-Warburg综合征（WWS）是一种遗传异质性疾病，通常表现为复杂的大脑和眼睛畸形以及先天性肌营养不良。ISPD基因的突变已被鉴定为WWS的最常见原因之一。
目的：当前的研究旨在确定我们受试者中严重的先天性脑积水和脑发育不良的原因。
方法：从胎儿的脐带血和父母的外周静脉血中提取基因组DNA。遗传分析包括全外显子组测序和qPCR。此外,进行了计算机模拟分析和细胞实验。
结果：我们在WWS胎儿的ISPD基因中鉴定出外显子7至9的新纯合缺失。计算机模拟分析揭示了ISPD的C末端结构域中的缺陷结构域结构。对静电势能的分析表明，在突变体ISPD基因（ISPD-delex7-9）的表面上形成了新的结合袋。突变体ISPD的细胞研究显示其细胞定位发生了显着变化，与野生型ISPD相比，ISPD-delex7-9蛋白从细胞质转移到细胞核，主要存在于细胞质中。
结论：本研究扩展了ISPD突变引起的WWS突变谱。重要的是,我们的工作表明,当核型或染色体微阵列分析不能提供明确的诊断时,对于患有先天性脑积水和脑畸形的胎儿,全外显子组测序可被视为一种诊断选择.
目的：当前的研究旨在确定我们受试者中严重的先天性脑积水和脑发育不良的原因。
方法：从胎儿的脐带血和父母的外周静脉血中提取基因组DNA。
结果：我们在WWS胎儿的ISPD基因中鉴定出外显子7至9的新纯合缺失。
结论：本研究扩展了ISPD突变引起的WWS突变谱。
