遗传性对称性色素异常症ADAR1基因突变检测

发布时间：2018-05-06 04:29

本文选题：遗传性对称性色素异常症 + ADAR1基因　；参考：《济南大学》2012年硕士论文

【摘要】：研究背景遗传性对称性色素异常症（Dyschromatosis symmetric hereditaria，DSH,MIM127400），又名Dohi对称性肢端色素沉着症,为常染色体显性遗传的良性皮肤病，主要临床特点是肢体末端由色素沉着和色素减退形成的网状斑，皮损主要分布于手背及脚背，部分患者在面部可有雀斑样损坏。本病常于婴儿期或者儿童期发病，青春期停止发展，并持续终生。2003年，张学军等采用全基因组扫描的方法对2个家系进行分析，第一次将本病致病基因定位在1q11-1q21区间约116cM的区域随后，日本学者Miyamura等对四个DSH家系进行全基因组扫描，，将本病的致病基因精细定位于1q21.3约500kb的区域内，并在这四个家系中均发现双链RNA特异性腺苷脱氨酶基因（DSRAD/ADAR1基因）的杂合突变，本突变在正常对照中未发现，证明这些碱基的改变是突变不而是多态，因此首次确定了DSRAD/ADAR1基因为本病的致病基因。DSRAD/ADAR1基因是一种双链RNA特异性腺昔脱氨酶,主要生物学功能包括RNA编辑和诱导蛋白质在核内的翻译。该基因所编码的双链RNA特异性的腺苷酸脱氨酶选择性的作用于前体信使RNA,将特殊位点上的腺嘌呤核苷(A)经过脱氨基作用转换成次黄嘌呤核苷(I),次黄嘌呤核苷在碱基配对中相当于鸟嘌呤(G)和胞嘧啶(C)的配对,导致双链RNA结构的不稳定及mRNA降解,并由此产生特定的生理学效应。迄今为止，国内外共发现了121个有关DSH的ADAR1基因突变位点，遗憾的是，没有发现热点突变。本研究收集4个DSH散发病例，通过DNA直接测序对其ADAR1基因进行了检测。目的对4个散发的遗传性对称性色素异常症病例的ADAR1基因进行突变检测。方法收集整理4个散发的遗传性对称性色素异常症患者的临床资料。获得知情同意后，抽取患者血样，提取患者外周血脱氧核糖核苷酸（DNA），采用聚合酶链反应扩增患者和100名无亲缘关系的正常对照个体ADAR1基因的全部外显子序列，然后对P C R扩增产物直接测序并进行序列分析，检测该基因突变。结果通过对4个散发的遗传性对称性色素异常症患者ADAR1基因的突变检测，检测到1个曾被报道过的错义突变3463C T (p.R1155W)和两个未曾报道的突变：1605delT (p.F535fs)框移突变和c.1630C T (p.R544x)无义突变。而在100例正常对照中均为发现上述突变。结论本研究通过PCR及DNA测序，发现了2个新的突变，包括一个框移突变和一个无义突变。进一步丰富了ADAR1基因数据库，为研究遗传性对称性色素异常症的发病机理及其基因型和表型之间的关系提供了新的数据。同时为将来这四个病例进行产前诊断或孕前诊断、提供遗传学咨询、阻断本病在家系中的遗传奠定了重要的基础。
[Abstract]:Background Dyschromatosis symmetric dyschromatosis symmetric hereditariade MIM127400, also known as Dohi symmetries, is an autosomal dominant benign skin disease characterized by pigmentation and hypochromatic reticular plaques at the extremities. Skin lesions are mainly distributed on the back of the hand and the back of the foot, and some patients may have freckle damage on the face. The disease often occurs in infancy or childhood, stops developing during puberty, and lasts for life. In 2003, Zhang Xuejun and others used a genome-wide scanning method to analyze two families. For the first time, the disease-causing gene was located in the region of the 1q11-1q21 region about 116cM. Then, Japanese scholar Miyamura et al scanned the whole genome of four DSH families, and mapped the disease-causing gene in the region of 1q21.3 about 500kb. Heterozygous mutations of the double stranded RNA specific adenosine deaminase gene (DSRAD / ADAR1 gene) were found in all four families, and this mutation was not found in normal controls, indicating that the changes in these bases were not mutations but polymorphic. Therefore, it is the first time that the DSRAD/ADAR1 gene. DSRAD / ADAR1 gene is a double stranded RNA specific adenodeaminase. Its main biological functions include RNA editing and inducing protein translation in the nucleus. The double-stranded adenylate deaminase encoded by the gene selectively acts on the precursor messenger RNAs, converting adenine nucleoside (A) at specific sites into Hypoxanthine nucleoside (I), which is in the base of the nucleoside Hypoxanthine (Hypoxanthine). A pair corresponding to guanine and cytosine C) in the base pairing. It leads to instability of double stranded RNA structure and degradation of mRNA, resulting in specific physiological effects. Up to now, 121 ADAR1 mutation sites related to DSH have been found at home and abroad, but unfortunately, no hot spot mutations have been found. In this study, four sporadic DSH cases were collected and their ADAR1 genes were detected by DNA sequencing. Objective to detect the mutation of ADAR1 gene in 4 sporadic cases of hereditary symmetrical dystrophy. Methods the clinical data of 4 sporadic patients with dystrophy of hereditary symmetry were collected. After obtaining informed consent, all exon sequences of ADAR1 gene were amplified by polymerase chain reaction (PCR) from patients' blood samples, DNA of deoxyribonucleotides (DNA) from peripheral blood of patients and 100 unrelated normal individuals. The PCR products were sequenced and sequenced to detect the mutation. Results by detecting the ADAR1 gene mutations in 4 sporadic patients with dystrophy, a previously reported missense mutation of 3463C T / p. R1155W) and two unreported mutations: 1 / 1605delT / p. F535fs) and c. 1630C / T / p. R544x) were detected. These mutations were found in 100 normal controls. Conclusion in this study, two new mutations were identified by PCR and DNA sequencing, including one box shift mutation and one nonsense mutation. It further enriches the ADAR1 gene database and provides new data for the study of the pathogenesis and the relationship between genotypes and phenotypes of hereditary symmetric pigmented disorders. At the same time, it lays an important foundation for prenatal diagnosis or pre-pregnancy diagnosis in the future, providing genetic counseling and blocking the inheritance of the disease in the home line.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R758.5

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