应用全基因组关联分析定位高度近视易感基因和应用外显子组测序分析大动脉转位致病基因

发布时间：2018-10-13 09:03

【摘要】：全基因组关联分析(GWAS)和全基因组外显子测序是定位疾病相关基因的有效手段,本论文主要内容是通过对高度近视的全基因组关联分析确定中国人群高度近视易感基因及利用全基因组外显子测序对大动脉转位表型不一致同卵双胞胎进行致病基因筛查。高度近视是指屈光度小于-6.00D或眼轴长度大于26mm的极端近视情况,尽管研究表明遗传因素在高度近视发生中起重要作用,但是其易感基因尚不明确。为了定位中国人群高度近视易感基因,开展了基于DNA混合池(DNA pooling)的全基因组关联分析。首先,在476例高度近视患者和275例健康对照中通过对MIR100HG和BLID基因区域的19个标签SNP进行分型和关联分析,排除了前人在日本人群定位的高度近视易感基因对中国人群易感性的贡献(全部标签SNP关联结果显著性均大于0.05),提示中国人群拥有自己特异的遗传易感性。以此为基础,对504例高度近视患者和276例健康对照进行基于ENA pooling的全基因组关联分析,并通过个体分型对关联结果进行验证,最终获得9个与疾病显著相关基因区域。通过对相关区域的功能分析定位PDE4B基因内含子上的rs10889602为候选易感位点(pooling p=1.38×10-6,个体分型p=0.0198)。进一步在来自两个不同人群队列的总计1,606例患者和1,509例对照中对该位点进行重复验证,最终整合所有结果认为rs10889602与中国人群高度近视易感性存在关联(pmeta=3.72×10-3)。同时在合作者的研究中证实抑制PDE4B基因功能可以诱导豚鼠产生近视表型。大动脉转位是紫绀型先天性心脏病的一种,其致病机制至今仍没有定论。为了验证遗传因素在大动脉转位发病中的作用,对一方患病、一方正常的一对同卵双胞胎进行全基因组外显子测序。高通量测序总计获得了49个在双胞胎间存在差异的突变位点,通过质谱分型证实这49个位点全部来源于测序错误。同时,插入缺失分析和拷贝数变异分析也未发现确证的差异。进一步的分析发现双胞胎均在调控不对称发育的NOTCH1基因上存在影响蛋白功能的错义突变(G1437R)。该基因在前人报道中是法洛氏四联症及主动脉瓣狭窄的致病基因。尽管未能证实体细胞突变在双胞胎差异表型中的贡献,研究结果仍提示遗传因素在大动脉转位中具有重要作用。
[Abstract]:Genome-wide association analysis (GWAS) and genomic exon sequencing are effective methods for locating disease-related genes. The main content of this thesis is to identify the susceptible genes of high myopia in Chinese population by the whole genome association analysis of high myopia and to screen the pathogenetic genes of the identical twins with different phenotypes of transposition of the great arteries by using the whole genome exon sequencing. High myopia refers to extreme myopia whose diopter is less than -6.00D or axial length is larger than 26mm. Although genetic factors play an important role in the development of high myopia, its susceptibility genes are not clear. In order to localize high myopia susceptibility genes in Chinese population, a genomic association analysis based on DNA mixed pool (DNA pooling) was carried out. First of all, in 476 patients with high myopia and 275 healthy controls, 19 tagged SNP in the MIR100HG and BLID gene regions were classified and analyzed by association analysis. The contribution of high myopia susceptibility genes located in Japanese population to susceptibility of Chinese population was excluded (all the SNP association results were significant higher than 0. 05), which suggested that Chinese population had their own specific genetic susceptibility. On the basis of this, 504 patients with high myopia and 276 healthy controls were analyzed for the whole genome association based on ENA pooling, and the association results were verified by individual typing. Finally, 9 significant gene regions associated with the disease were obtained. The rs10889602 on intron of PDE4B gene was identified as a candidate susceptibility site by functional analysis of related regions (pooling p1. 38 脳 10 ~ (-6), individual typing p0. 0198). Further repeated validation of this locus was performed in a total of 1606 patients from two different cohorts and 1509 controls. Finally, all the results were integrated and concluded that rs10889602 was associated with high myopia susceptibility in Chinese population (pmeta=3.72 脳 10-3). Inhibition of PDE4B gene function can induce myopia phenotype in guinea pigs. Transposition of great arteries is a cyanotic congenital heart disease, the pathogenesis of which is still unclear. In order to verify the role of genetic factors in the pathogenesis of transposition of the great arteries, a pair of identical twins with one disease and one normal were sequenced. A total of 49 mutation sites with differences between twins were obtained by high throughput sequencing, all of which were confirmed by mass spectrometry typing. At the same time, insertion deletion analysis and copy number variation analysis also found no confirmed differences. Further analysis revealed that both twins had missense mutations (G1437R) that affect protein function in the NOTCH1 gene that regulates asymmetric development. This gene has been reported to be a pathogenic gene for tetralogy of Fallot and aortic valve stenosis. Although the contribution of somatic mutation to the differential phenotypes of twins has not been confirmed, the results suggest that genetic factors play an important role in the transposition of the great arteries.
【学位授予单位】：中国科学院北京基因组研究所
【学位级别】：博士
【学位授予年份】：2011
【分类号】：R778.11

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