Abstract：
Hereditary multiple exostosis (HME) is an autosomal dominant skeletal disorder characterized by the development of multiple cartilage-covered tumors on the external surfaces of bones (osteochondromas). Most of HME cases result from heterozygous loss-of-function mutations in EXT1 or EXT2 gene.
Clinical examination was performed to diagnose the patients: Whole exome sequencing (WES) was used to identify pathogenic mutations in the proband, which is confirmed by Sanger sequencing and co-segregation analysis: qRT-PCR was performed to identify the mRNA expression level of EXT1 in patient peripheral blood samples: minigene splicing assay was performed to mimic the splicing process of EXT1 variants in vitro.
We evaluated the pathogenicity of EXT1 c.1056 + 1G > T in a Chinese family with HME. The clinical, phenotypic, and genetic characterization of patients in this family were described. The variant was detected by whole-exome sequencing (WES) and confirmed by Sanger sequencing. Sequencing of the RT-PCR products from the patient\'s blood sample identified a large deletion (94 nucleotides), which is the whole exome 2 of the EXT1 cDNA. Splicing assay indicated that the mutated minigene produced alternatively spliced transcripts, which cause a frameshift resulting in an early termination of protein expression.
Our study establishes the pathogenesis of the splicing mutation EXT1 c.1056 + 1G > T to HME and provides scientific foundation for accurate diagnosis and precise medical intervention for HME.
Clinical examination was performed to diagnose the patients: Whole exome sequencing (WES) was used to identify pathogenic mutations in the proband, which is confirmed by Sanger sequencing and co-segregation analysis: qRT-PCR was performed to identify the mRNA expression level of EXT1 in patient peripheral blood samples: minigene splicing assay was performed to mimic the splicing process of EXT1 variants in vitro.
We evaluated the pathogenicity of EXT1 c.1056 + 1G > T in a Chinese family with HME. The clinical, phenotypic, and genetic characterization of patients in this family were described. The variant was detected by whole-exome sequencing (WES) and confirmed by Sanger sequencing. Sequencing of the RT-PCR products from the patient\'s blood sample identified a large deletion (94 nucleotides), which is the whole exome 2 of the EXT1 cDNA. Splicing assay indicated that the mutated minigene produced alternatively spliced transcripts, which cause a frameshift resulting in an early termination of protein expression.
Our study establishes the pathogenesis of the splicing mutation EXT1 c.1056 + 1G > T to HME and provides scientific foundation for accurate diagnosis and precise medical intervention for HME.
摘要：
遗传性多发性外生症（HME）是一种常染色体显性骨骼疾病，其特征是在骨骼的外表面上发展出多个软骨覆盖的肿瘤（骨软骨瘤）。大多数HME病例是由EXT1或EXT2基因中的杂合功能丧失突变引起的。
进行临床检查以诊断患者：使用全外显子组测序（WES）来鉴定先证者中的致病性突变，Sanger测序和共分离分析证实了这一点:进行qRT-PCR以鉴定患者外周血样品中EXT1的mRNA表达水平:进行小基因剪接测定以模拟体外EXT1变体的剪接过程。
我们评估了EXT1c.1056+1G>T在中国HME家族中的致病性。临床，表型，并对该家族患者的基因特征进行了描述。通过全外显子组测序(WES)检测变体,并通过Sanger测序确认。来自患者血液样本的RT-PCR产物的测序鉴定出一个大的缺失(94个核苷酸),它是EXT1cDNA的整个外显子组2。剪接分析表明，突变的小基因产生了选择性剪接的转录本，这导致移码，导致蛋白质表达的早期终止。
我们的研究建立了剪接突变EXT1c.10561G>T对HME的发病机制，为HME的准确诊断和精确的医疗干预提供了科学依据。
进行临床检查以诊断患者：使用全外显子组测序（WES）来鉴定先证者中的致病性突变，Sanger测序和共分离分析证实了这一点:进行qRT-PCR以鉴定患者外周血样品中EXT1的mRNA表达水平:进行小基因剪接测定以模拟体外EXT1变体的剪接过程。
我们评估了EXT1c.1056+1G>T在中国HME家族中的致病性。临床，表型，并对该家族患者的基因特征进行了描述。通过全外显子组测序(WES)检测变体,并通过Sanger测序确认。来自患者血液样本的RT-PCR产物的测序鉴定出一个大的缺失(94个核苷酸),它是EXT1cDNA的整个外显子组2。剪接分析表明，突变的小基因产生了选择性剪接的转录本，这导致移码，导致蛋白质表达的早期终止。
我们的研究建立了剪接突变EXT1c.10561G>T对HME的发病机制，为HME的准确诊断和精确的医疗干预提供了科学依据。
