Exome sequencing

外显子组测序
  • 文章类型: Journal Article
    遗传检查在神经系统疾病的临床评估中变得越来越普遍。我们评估了中老年神经系统患者的产量,在现实世界的背景下。这项回顾性研究包括368名50岁及以上的以色列患者(男性202人[54.9%]),他们在2017年至2023年中期期间被转诊到一家神经遗传学诊所。所有人都有神经系统疾病,没有先前的分子诊断。人口统计,从医疗记录中收集临床和遗传数据.在诊所进行首次遗传咨询的平均年龄为62.3±7.8岁(范围为50-85岁),转诊的主要适应症是神经肌肉,运动和脑血管疾病,以及认知障碍和痴呆症。368名患者中,245(66.6%)接受了基因检测,包括外显子组测序(ES),核苷酸重复扩增分析,检测特定的突变,靶向基因组测序或染色体微阵列分析。总的来说,80名患者(21.7%)因36种疾病接受了分子诊断,占进行基因检测的患者的32.7%。诊断率最高的是神经肌肉(58/186患者[31.2%],148名受测者中的39.2%)和运动障碍(14/79[17.7%]患者,48个测试中的29.2%),但对其他疾病来说更低。核苷酸重复扩增和ES的测试为28/73(38.4%)和19/132(14.4%)个体提供了诊断,分别。根据我们的发现,遗传检查和测试在50岁以上的神经系统患者的诊断过程中很有用,特别是对于那些有神经肌肉和运动障碍的人。
    Genetic workup is becoming increasingly common in the clinical assessment of neurological disorders. We evaluated its yield among middle-aged and elderly neurological patients, in a real-world context. This retrospective study included 368 consecutive Israeli patients aged 50 years and older (202 [54.9%] males), who were referred to a single neurogenetics clinic between 2017 and mid-2023. All had neurological disorders, without a previous molecular diagnosis. Demographic, clinical and genetic data were collected from medical records. The mean age at first genetic counseling at the clinic was 62.3 ± 7.8 years (range 50-85 years), and the main indications for referral were neuromuscular, movement and cerebrovascular disorders, as well as cognitive impairment and dementia. Out of the 368 patients, 245 (66.6%) underwent genetic testing that included exome sequencing (ES), analysis of nucleotide repeat expansions, detection of specific mutations, targeted gene panel sequencing or chromosomal microarray analysis. Overall, 80 patients (21.7%) received a molecular diagnosis due to 36 conditions, accounting for 32.7% of the patients who performed genetic testing. The diagnostic rates were highest for neuromuscular (58/186 patients [31.2%] in this group, 39.2% of 148 tested individuals) and movement disorders (14/79 [17.7%] patients, 29.2% of 48 tested), but lower for other disorders. Testing of nucleotide repeat expansions and ES provided a diagnosis to 28/73 (38.4%) and 19/132 (14.4%) individuals, respectively. Based on our findings, genetic workup and testing are useful in the diagnostic process of neurological patients aged ≥50 years, in particular for those with neuromuscular and movement disorders.
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  • 文章类型: Journal Article
    背景:患有原发性硬化性胆管炎(PSC)的人一生中患胆道癌(BTC)的风险为20%。使用全外显子组测序,我们表征了来自具有潜在PSC的BTC的组织样本中的基因组改变。
    方法:我们从福尔马林固定的,来自PSC和BTC患者的52例切除或活检标本的石蜡包埋肿瘤和配对非肿瘤组织,并进行了全外显子组测序。在拷贝数分析之后,变体调用,和过滤,通过通路分析评估了推定的PSC-BTC相关基因,并将其注释为靶向癌症治疗.
    结果:我们在2个或更多样本中鉴定了53个候选癌症基因,共有123个非同义改变通过过滤阈值。在确定的基因中,19%以前没有与BTC有牵连,包括CNGA3、KRT28和EFCAB5。另一个子集包含先前与肝胰胆管癌有关的基因,如ARID2、ELF3和PTPRD。最后,我们确定了与多种癌症有关的基因子集,例如肿瘤抑制基因TP53,CDKN2A,SMAD4和RNF43以及癌基因KRAS,ERBB2和BRAF。在51.9%的样品中发现了焦点拷贝数变异。潜在可操作基因的改变,包括ERBB2,MDM2和FGFR3被识别和RTK/RAS的改变(p=0.036),TP53(p=0.04),和PI3K(p=0.043)通路与总生存率降低显著相关。
    结论:在PSC相关BTC的整个外显子组表征中,我们描述了PSC特异性和普遍癌基因.我们的发现为更好地了解PSC中BTC的发展提供了机会,并可用作开发个性化治疗方法的平台。
    BACKGROUND: People with primary sclerosing cholangitis (PSC) have a 20% lifetime risk of biliary tract cancer (BTC). Using whole-exome sequencing, we characterized genomic alterations in tissue samples from BTC with underlying PSC.
    METHODS: We extracted DNA from formalin-fixed, paraffin-embedded tumor and paired nontumor tissue from 52 resection or biopsy specimens from patients with PSC and BTC and performed whole-exome sequencing. Following copy number analysis, variant calling, and filtering, putative PSC-BTC-associated genes were assessed by pathway analyses and annotated to targeted cancer therapies.
    RESULTS: We identified 53 candidate cancer genes with a total of 123 nonsynonymous alterations passing filtering thresholds in 2 or more samples. Of the identified genes, 19% had not previously been implicated in BTC, including CNGA3, KRT28, and EFCAB5. Another subset comprised genes previously implicated in hepato-pancreato-biliary cancer, such as ARID2, ELF3, and PTPRD. Finally, we identified a subset of genes implicated in a wide range of cancers such as the tumor suppressor genes TP53, CDKN2A, SMAD4, and RNF43 and the oncogenes KRAS, ERBB2, and BRAF. Focal copy number variations were found in 51.9% of the samples. Alterations in potential actionable genes, including ERBB2, MDM2, and FGFR3 were identified and alterations in the RTK/RAS (p = 0.036), TP53 (p = 0.04), and PI3K (p = 0.043) pathways were significantly associated with reduced overall survival.
    CONCLUSIONS: In this exome-wide characterization of PSC-associated BTC, we delineated both PSC-specific and universal cancer genes. Our findings provide opportunities for a better understanding of the development of BTC in PSC and could be used as a platform to develop personalized treatment approaches.
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  • 文章类型: Journal Article
    背景:II型戊二酸尿症(GA2)是一种罕见的常染色体隐性遗传的遗传性疾病。GA2相应基因的双剂量突变,EFDH,ETFA,和ETFB,导致脂肪酸分解代谢的缺陷,和氨基酸导致广谱表型,包括肌肉无力,发育迟缓,和癫痫发作。这三个基因的产物在将电子转移到电子传递链(ETC)中具有至关重要的作用,但不直接参与ETC复合物。
    方法:这里,通过使用外显子组测序,一个19岁女孩的周期性隐匿性胃肠道并发症的原因在经过多年的诊断试验后得到解决。新变体的蛋白质建模作为其另一个验证线。
    结果:外显子组测序(ES)在ETFDH中鉴定出两种变体:ETFDH:c.926T>G和ETFDH:c.1141G>C。在这种情况下,这些变体可能会导致危机。据我们所知,在写这篇手稿的时候,变体ETFDH:c.926T>G是首次报道。病例的临床表现和病理分析与分子检查结果一致。蛋白质模型提供了另一个证据线证明新变体的致病性。ETFDH:c.926T>G在此首次报告与因果关系GA2有关。
    结论:鉴于这种情况下症状较轻,对复合杂合子突变引起的GA2病例进行了回顾,突出这些患者的症状范围,从轻度疲劳到更严重的结果。结果强调了综合遗传分析在阐明GA2临床表现谱和指导个性化治疗策略方面的重要性。
    BACKGROUND: Glutaric aciduria type II (GA2) is a rare genetic disorder inherited in an autosomal recessive manner. Double dosage mutations in GA2 corresponding genes, ETFDH, ETFA, and ETFB, lead to defects in the catabolism of fatty acids, and amino acids lead to broad-spectrum phenotypes, including muscle weakness, developmental delay, and seizures. product of these three genes have crucial role in transferring electrons to the electron transport chain (ETC), but are not directly involve in ETC complexes.
    METHODS: Here, by using exome sequencing, the cause of periodic cryptic gastrointestinal complications in a 19-year-old girl was resolved after years of diagnostic odyssey. Protein modeling for the novel variant served as another line of validation for it.
    RESULTS: Exome Sequencing (ES) identified two variants in ETFDH: ETFDH:c.926T>G and ETFDH:c.1141G>C. These variants are likely contributing to the crisis in this case. To the best of our knowledge at the time of writing this manuscript, variant ETFDH:c.926T>G is reported here for the first time. Clinical manifestations of the case and pathological analysis are in consistent with molecular findings. Protein modeling provided another line of evidence proving the pathogenicity of the novel variant. ETFDH:c.926T>G is reported here for the first time in relation to the causation GA2.
    CONCLUSIONS: Given the milder symptoms in this case, a review of GA2 cases caused by compound heterozygous mutations was conducted, highlighting the range of symptoms observed in these patients, from mild fatigue to more severe outcomes. The results underscore the importance of comprehensive genetic analysis in elucidating the spectrum of clinical presentations in GA2 and guiding personalized treatment strategies.
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  • 文章类型: Journal Article
    食管小细胞癌(SCCE)是一种罕见且高度恶性的食管癌,没有标准的治疗方法。面临着对传统疗法的抵抗的挑战。这项研究介绍了一名接受化学免疫疗法治疗的广泛阶段和两名有限阶段SCCE患者的病例。两名有限阶段的患者在治疗后接受了手术,并经历了显着且持久的积极反应。这代表了新辅助化学免疫疗法在局限期SCCE患者中的首次应用。此外,对病例患者进行综合免疫组织化学分析和全外显子组测序。研究结果表明,SCCE肿瘤中CD8T细胞的浸润和PD-L1的表达是接受化学免疫疗法的SCCE患者反应良好的关键因素。
    Small cell carcinoma of the esophagus (SCCE) is a rare and highly malignant type of esophageal cancer with no standard treatment, facing challenges of resistance to conventional therapies. This study presents the cases of one extensive-stage and two limited-stage SCCE patients treated with chemoimmunotherapy. The two limited-stage patients underwent surgery post-treatment and experienced notable and enduring positive responses. This represents the first documented application of neoadjuvant chemoimmunotherapy in limited-stage SCCE patients. Additionally, comprehensive immunohistochemical analysis and whole exome sequencing were performed on the case patients. The findings revealed that infiltration of CD8+ T cells and PD-L1 expression in the SCCE tumor were key factors for favorable responses in SCCE patients receiving chemoimmunotherapy.
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  • 文章类型: Journal Article
    背景:SLC29A3基因,它编码核苷转运蛋白,主要位于细胞内膜。该基因的突变可以引起各种临床表现,包括H综合征,心肌硬化,Faisalabad组织细胞增生症,和胰岛素依赖型糖尿病的色素沉着多毛症。这项研究的目的是介绍两名患有H综合征的伊朗患者,并描述SLC29A3基因中的一种新的开始丢失突变。
    方法:在本研究中,我们采用全外显子组测序(WES)作为一种方法,在一名16岁女孩及其8岁哥哥中鉴定有助于H综合征发展的遗传变异.这些兄弟姐妹是伊朗家庭的一部分,父母是近亲。为了证实鉴定出的变异体的致病性,我们利用了计算机工具和交叉引用的各种数据库来确认它的新颖性。此外,我们进行了一项共隔离研究,并通过Sanger测序验证了受影响患者父母中变异体的存在.
    结果:在我们的研究中,我们发现了一个新的起始丢失突变(c.2T>A,p.Met1Lys)在SLC29A3基因中,在两个患者中都发现了。使用Sanger测序的共分离分析证实该变体是从亲本遗传的。为了评估这种突变的潜在致病性和新颖性,我们查阅了各种数据库。此外,我们使用生物信息学工具来预测突变的SLC29A3蛋白的三维结构。进行这些分析的目的是提供对所鉴定的突变对SLC29A3蛋白的结构和功能的功能影响的有价值的见解。
    结论:我们的研究为支持SLC29A3基因突变与H综合征之间的关联提供了越来越多的证据。与SLC29A3相关疾病的分子分析对于理解变异范围和提高对H综合征的认识至关重要。最终目标是促进早期诊断和适当治疗。在先证者中发现这种新颖的双等位基因变体进一步强调了利用遗传测试方法的重要性,如WES,作为具有这种特殊情况的个人的可靠诊断工具。
    BACKGROUND: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene.
    METHODS: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing.
    RESULTS: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein.
    CONCLUSIONS: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.
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  • 文章类型: Journal Article
    Brugada综合征(BrS)是一种遗传性心律失常综合征,其中心脏钠通道SCN5A(NaV1.5)中的突变约占病例的20%。钠通道修饰基因的突变可能会导致其他BrS病例,尽管BrS可能是多基因的,因为已经确定了与BrS相关的常见SNP。最近的分析,然而,建议SCN5A应被视为BrS的唯一单原因。
    我们试图重新评估一个大型多代家族中BrS的遗传基础,该家族在GPD1L中具有推定的突变,该突变会影响体外NaV1.5的表面膜表达。
    使用Illumina全局筛选阵列在家族中进行精细连锁作图。进行先证者的全外显子组测序以鉴定罕见的变异和突变,Sanger测序用于分析先前报道的BrS的风险单核苷酸多态性(SNP)。
    连锁分析将先前报道的微卫星连锁区域的大小减小至约3Mb。GPD1L-A280V是唯一的编码非同义变异,在连锁区域内的先证子中以小于1%的等位基因频率存在。在与BrS相关的基因中,受影响的个体的连锁区域之外没有罕见的非同义变体。已知易患BrS的风险SNP在受影响的家庭成员中被过度代表。
    一起,我们的数据提示GPD1L-A280V仍然是这个多代家族中最可能的BrS病因.尽管考虑到BrS的遗传不确定性,在解释变异致病性时应格外小心,我们的数据支持将其他推定的BrS基因纳入临床遗传小组.
    UNASSIGNED: Brugada Syndrome (BrS) is an inherited arrhythmia syndrome in which mutations in the cardiac sodium channel SCN5A (NaV1.5) account for approximately 20% of cases. Mutations in sodium channel-modifying genes may account for additional BrS cases, though BrS may be polygenic given common SNPs associated with BrS have been identified. Recent analysis, however, has suggested that SCN5A should be regarded as the sole monogenic cause of BrS.
    UNASSIGNED: We sought to re-assess the genetic underpinnings of BrS in a large mutligenerational family with a putative mutation in GPD1L that affects surface membrane expression of NaV1.5 in vitro.
    UNASSIGNED: Fine linkage mapping was performed in the family using the Illumina Global Screening Array. Whole exome sequencing of the proband was performed to identify rare variants and mutations, and Sanger sequencing was used to assay previously-reported risk single nucleotide polymorphsims (SNPs) for BrS.
    UNASSIGNED: Linkage analysis decreased the size of the previously-reported microsatellite linkage region to approximately 3 Mb. GPD1L-A280V was the only coding non-synonymous variation present at less than 1% allele frequency in the proband within the linkage region. No rare non-synonymous variants were present outside the linkage area in affected individuals in genes associated with BrS. Risk SNPs known to predispose to BrS were overrepresented in affected members of the family.
    UNASSIGNED: Together, our data suggest GPD1L-A280V remains the most likely cause of BrS in this large multigenerational family. While care should be taken in interpreting variant pathogenicity given the genetic uncertainty of BrS, our data support inclusion of other putative BrS genes in clinical genetic panels.
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  • 文章类型: Journal Article
    背景:塔顿-布朗-拉赫曼综合征(TBRS)是一种罕见的疾病,由DNMT3A杂合致病变异引起,并在2014年首次描述。TBRS的特征是过度生长,智力残疾,面部畸形,肌张力减退和肌肉骨骼特征,以及神经和精神特征。心脏表现也有报道,主要是先天性畸形,如房间隔缺损,室间隔缺损和心脏瓣膜病。主动脉扩张很少被描述。
    方法:这里我们对8个以前未报告的个体进行了详细的临床和分子描述,谁有TBRS和动脉扩张和/或夹层,主要是胸主动脉瘤(TAA)。我们还回顾了先前发表的7例TBRS患者的TAA病例,以尝试更好地描绘血管表型并确定这种情况的具体随访。
    结果:我们包括8例新的TBRS患者,这些患者表现为主要累及主动脉的动脉瘤。其中三名患者进行了需要进行关键手术的解剖。
    结论:动脉动脉瘤和夹层具有潜在的致命性,年龄依赖性表现。TBRS患者的主动脉疾病患病率远远超过一般人群的预期。这个队列,与以前发表的个人一起,说明了考虑扩张/解剖的重要性,主要在主动脉,也在其他动脉。因此,动脉血管无力也可能是TBRS的主要特征,建议进行血管监测。
    BACKGROUND: Tatton-Brown-Rahman syndrome (TBRS) is a rare disorder, caused by DNMT3A heterozygous pathogenic variants, and first described in 2014. TBRS is characterised by overgrowth, intellectual disability, facial dysmorphism, hypotonia and musculoskeletal features, as well as neurological and psychiatric features. Cardiac manifestations have also been reported, mainly congenital malformations such as atrial septal defect, ventricular septal defect and cardiac valvular disease. Aortic dilatation has rarely been described.
    METHODS: Here we have undertaken a detailed clinical and molecular description of eight previously unreported individuals, who had TBRS and arterial dilatation and/or dissection, mainly thoracic aortic aneurysm (TAA). We have also reviewed the seven previously published cases of TAA in individuals with TBRS to try to better delineate the vascular phenotype and to determine specific follow-up for this condition.
    RESULTS: We include eight new patients with TBRS who presented with arterial aneurysms mainly involving aorta. Three of these patients presented with dissection that required critical surgery.
    CONCLUSIONS: Arterial aneurysms and dissections are a potentially lethal, age-dependent manifestation. The prevalence of aortic disease in individuals with TBRS is far in excess of that expected in the general population. This cohort, together with individuals previously published, illustrates the importance to consider dilatation/dissection, mainly in aorta but also in other arteries. Arterial vascular weakness may therefore also be a cardinal feature of TBRS and vascular surveillance is recommended.
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  • 文章类型: Journal Article
    背景:遗传性视网膜营养不良(IRD)是全球范围内无法治愈的失明的主要原因之一。IRD是由编码视网膜必需蛋白的基因突变引起的,导致光感受器退化和视觉功能丧失。由于缺乏对其病理生理学的重要部分的了解,IRD产生了巨大的全球财务负担,分子诊断,以及几乎没有非姑息治疗方案。用于IRD的患者来源的诱导多能干细胞(iPSC)似乎是解决这些问题的绝佳选择,作为IRD病理生理学深入研究和测试新治疗方法的特殊工具。
    方法:从8名与PROM1相关的IRD患者的队列中,我们确定了3名患者携带相同的变体(c.1354dupT),但表达三种不同的IRD表型:锥形和杆状营养不良(CORD),色素性视网膜炎(RP),和Stargardt病4型(STGD4)。这三个目标患者,每个人都有一个健康的亲戚,接受了全面的眼科检查,并通过临床外显子组测序(CES)扩展了他们的遗传小组研究。随后,产生非整合性患者来源的iPSC,并对其进行充分表征.使用CRISPR/Cas9进行c.1354dupT突变的校正,并且在患者来源的iPSC系中通过流式细胞术和蛋白质印迹确认PROM1基因的遗传恢复。
    结果:CES显示,2名具有c.1354dupT突变的目标患者在与补体系统或光感受器分化和过氧化物酶体生物发生障碍相关的基因中呈现单等位基因变异,分别。证实了患者来源的iPSC细胞系的多能性和功能性,目标突变的校正完全恢复了基因修复的患者来源的iPSC系中编码Prominin-1(CD133)的能力。
    结论:PROM1基因的c.1354dupT突变与IRD的三种不同的AR表型相关。这种多向效应可能与视网膜营养不良相关的其他基因中单等位基因变体的影响有关。然而,需要提供进一步的证据。未来的实验应该包括基因编辑的患者来源的iPSC,因为它有潜力作为疾病建模工具来阐明这一问题。
    BACKGROUND: Inherited retinal dystrophies (IRD) are one of the main causes of incurable blindness worldwide. IRD are caused by mutations in genes that encode essential proteins for the retina, leading to photoreceptor degeneration and loss of visual function. IRD generates an enormous global financial burden due to the lack of understanding of a significant part of its pathophysiology, molecular diagnosis, and the near absence of non-palliative treatment options. Patient-derived induced pluripotent stem cells (iPSC) for IRD seem to be an excellent option for addressing these questions, serving as exceptional tools for in-depth studies of IRD pathophysiology and testing new therapeutic approaches.
    METHODS: From a cohort of 8 patients with PROM1-related IRD, we identified 3 patients carrying the same variant (c.1354dupT) but expressing three different IRD phenotypes: Cone and rod dystrophy (CORD), Retinitis pigmentosa (RP), and Stargardt disease type 4 (STGD4). These three target patients, along with one healthy relative from each, underwent comprehensive ophthalmic examinations and their genetic panel study was expanded through clinical exome sequencing (CES). Subsequently, non-integrative patient-derived iPSC were generated and fully characterized. Correction of the c.1354dupT mutation was performed using CRISPR/Cas9, and the genetic restoration of the PROM1 gene was confirmed through flow cytometry and western blotting in the patient-derived iPSC lines.
    RESULTS: CES revealed that 2 target patients with the c.1354dupT mutation presented monoallelic variants in genes associated with the complement system or photoreceptor differentiation and peroxisome biogenesis disorders, respectively. The pluripotency and functionality of the patient-derived iPSC lines were confirmed, and the correction of the target mutation fully restored the capability of encoding Prominin-1 (CD133) in the genetically repaired patient-derived iPSC lines.
    CONCLUSIONS: The c.1354dupT mutation in the PROM1 gene is associated to three distinct AR phenotypes of IRD. This pleotropic effect might be related to the influence of monoallelic variants in other genes associated with retinal dystrophies. However, further evidence needs to be provided. Future experiments should include gene-edited patient-derived iPSC due to its potential as disease modelling tools to elucidate this matter in question.
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  • 文章类型: Journal Article
    敲除GAS2(生长停滞特异性蛋白2),导致耳蜗管支持细胞中微管束的解体和不稳定,导致体内听力损失。然而,GAS2变异导致听力损失的分子机制尚不清楚.通过全外显子组测序,我们在GAS2中发现了一个新的杂合剪接变体(c.616-2A>G),这是在一个大型显性家族中与迟发性和进行性非综合征性听力损失(NSHL)分离的唯一候选突变.这种剪接突变引起内含子保留并产生C末端截短的蛋白质(命名为GAS2mu)。机械上,GAS2mu通过泛素-蛋白酶体途径的降解得到增强,表达GAS2mu的细胞表现出无序的微管束。此外,GAS2mu通过增加Bcl-xS/Bcl-xL比例而不是像野生型GAS2那样通过p53依赖性途径进一步促进细胞凋亡。表明GAS2mu作为毒性分子加剧细胞凋亡。我们的研究结果表明,GAS2的这种新型变体促进了其自身的蛋白质降解,微管解体和细胞凋亡,导致携带者听力损失。这项研究扩大了GAS2变异的范围,并阐明了潜在的致病机制,为未来研究预防GAS2相关进行性听力损失的新治疗策略奠定基础。
    Knockout of GAS2 (growth arrest-specific protein 2), causes disorganization and destabilization of microtubule bundles in supporting cells of the cochlear duct, leading to hearing loss in vivo. However, the molecular mechanism through which GAS2 variant results in hearing loss remains unknown. By Whole-exome sequencing, we identified a novel heterozygous splicing variant in GAS2 (c.616-2 A > G) as the only candidate mutation segregating with late-onset and progressive nonsyndromic hearing loss (NSHL) in a large dominant family. This splicing mutation causes an intron retention and produces a C-terminal truncated protein (named GAS2mu). Mechanistically, the degradation of GAS2mu via the ubiquitin-proteasome pathway is enhanced, and cells expressing GAS2mu exhibit disorganized microtubule bundles. Additionally, GAS2mu further promotes apoptosis by increasing the Bcl-xS/Bcl-xL ratio instead of through the p53-dependent pathway as wild-type GAS2 does, indicating that GAS2mu acts as a toxic molecule to exacerbate apoptosis. Our findings demonstrate that this novel variant of GAS2 promotes its own protein degradation, microtubule disorganization and cellular apoptosis, leading to hearing loss in carriers. This study expands the spectrum of GAS2 variants and elucidates the underlying pathogenic mechanisms, providing a foundation for future investigations of new therapeutic strategies to prevent GAS2-associated progressive hearing loss.
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