应用全外显子测序对一个遗传性痉挛性截瘫家系致病基因的研究

发布时间：2018-05-13 18:58

  本文选题：遗传性痉挛性截瘫 + 全外显子测序　； 参考：《青岛大学》2017年硕士论文

【摘要】：目的遗传性痉挛性截瘫(Hereditary Spastic Paraplegia,HSP)是一种具有高度临床和遗传异质性的神经退行性疾病,典型临床症状是双下肢进行性肌肉紧张、肌无力和痉挛状态。本研究旨在应用全外显子测序对一个中国汉族HSP家系的致病基因进行研究,为家系患者做出准确的基因诊断,为产前诊断和HSP致病机理的研究奠定基础。方法收集一个包含5代32人的HSP家系,绘制标准家系图,选取该家系Ⅲ代7人、Ⅳ代12人作为研究对象,采集外周抗凝血样并提取基因组DNA(g DNA)。对先证者(Ⅳ11)、先证者患病姐姐(Ⅳ8)和先证者未患病哥哥(Ⅳ9)进行一系列临床检查,包括病史采集、体格检查、颅脑磁共振检查。选取Ⅳ11、Ⅳ8和Ⅳ9的g DNA样本进行全外显子测序,运用SIFT、Poly Phen2、DNAMAN等生物信息学分析软件获取可疑致病基因突变位点。应用PCR扩增及Sanger测序的方法将可疑致病突变位点在该家系19名研究对象和50例与该家系无血缘关系的健康对照者中进行验证,分析该位点在家系内是否呈共分离,从而进一步验证该位点与该家系的关联性。结果临床检查结果:Ⅳ11和Ⅳ8均表现典型双下肢进行性痉挛性截瘫,无脊髓外其他系统症状,颅脑、颈椎、胸椎核磁共振检查均未见明显异常。基因检测结果:通过全外显子测序和Sanger测序验证,发现该家系中6例患者均携带SPAST(SPG4)上的同一突变位点(c.1606CT,p.Gln536X),家系中13例正常者和50例与该家系无血缘关系的健康对照者中均未发现该突变,表明这一突变位点在该家系中呈共分离。此外,该突变位点在国内外尚未报道,是一个新发现突变位点。结论结合临床症状和基因检测结果确诊先证者及家系其他患者所患疾病为单纯型遗传性痉挛性截瘫,新发现的SPAST(SPG4)上c.1606CT,p.Gln536X杂合突变是该HSP家系的致病基因突变,这不仅拓宽了SPAST(SPG4)基因突变谱,也为该家系产前诊断提供了依据,为研究HSP的发病机制奠定了理论基础。
[Abstract]:Objective hereditary spastic paraplegia (Spastic) is a neurodegenerative disease with high clinical and genetic heterogeneity. The typical clinical symptoms are progressive muscle tension, myasthenia and spasm of the lower extremities. The purpose of this study was to study the pathogenicity genes of a Chinese Han HSP family by using total exon sequencing, and to provide a basis for the prenatal diagnosis and the study of the pathogenesis of HSP in pedigrees. Methods A HSP pedigree consisting of 32 persons of 5 generations was collected, and the standard family map was drawn. Seven members of the third generation and 12 people of the fourth generation were selected as the research objects. Peripheral anticoagulant blood samples were collected and genomic DNA(g DNA was extracted. A series of clinical examinations were performed on the proband (鈪，

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