本文選題：精神發(fā)育遲滯　切入點：CC2D1A基因　出處：《西北大學》2012年博士論文　論文類型：學位論文

【摘要】：精神發(fā)育遲滯(mental retardation, MR)是一類常見的神經(jīng)、精神類疾病,以智力低下和社會適應能力不足為主要特征,發(fā)病于18周歲之前。MR的致病原因較為復雜,包括遺傳與環(huán)境兩大類因素,其中約有2/3的病例具有遺傳基礎。秦巴山區(qū)是我國MR的高發(fā)地區(qū)之一,MR的總患病率約為2.70%,兒童患病率約為2.78%,是全國平均水平的2-3倍,給當?shù)氐纳鐣?jīng)濟文化發(fā)展帶來極大的負擔。因此,從遺傳學的角度對秦巴山區(qū)MR的致病機制進行研究,是一項亟待持續(xù)、深入開展的有意義的工作。 由遺傳因素所致的MR具有很高的遺傳異質(zhì)性,目前已發(fā)現(xiàn)許多基因或位點與之相關。由于MR患者以男性居多,故長期以來對該病的分子遺傳學研究主要集中于X染色體,而對常染色體則很少涉及。然而,近期研究表明常染色體基因可能在智力或認知能力的遺傳中發(fā)揮著重大作用,對秦巴山區(qū)患病家系的調(diào)查也表明當?shù)睾芏郙R家系符合常染色體隱性遺傳的模式,因此本文選擇了3個位于常染色體的MR候選基因(CC2D1A、 CC2D2A、CRBN)作為研究對象,來探討這些基因與秦巴山區(qū)人群的MR之間是否具有相關性。 CC2D1A和CC2D2A基因所編碼的蛋白質(zhì)均通過其C2結(jié)構(gòu)域參與Ca2+調(diào)控的信號通路,對神經(jīng)可塑性與神經(jīng)系統(tǒng)的發(fā)育產(chǎn)生影響；CRBN基因的蛋白質(zhì)產(chǎn)物屬于ATP依賴的Lon蛋白酶,可對中樞神經(jīng)系統(tǒng)的多個信號通路進行調(diào)控。研究表明這3個基因的突變分別導致國外一些家系的非特異性MR(即除了智力低下及社會適應能力不足之外,沒有其它臨床體征的MR)。 為了避免傳統(tǒng)的病例-對照樣本可能存在人群層化而影響結(jié)果的準確性,本文以來自秦巴山區(qū)的172個MR核心家系作為樣本,在上述3個基因內(nèi)部一共選擇了14個SNP位點作為遺傳標記,進行關聯(lián)研究。據(jù)我們所知,這也是第一次對這3個基因與MR之間的關系進行以基于家系的隨機人群為對象的關聯(lián)分析�；蚍中筒捎镁酆厦告準椒磻�-限制性片段長度多態(tài)性(PCR-RFLP)和PCR-單鏈構(gòu)象多態(tài)性(PCR-SSCP)法(結(jié)合DNA測序)。等位基因頻率和基因型頻率、哈代-溫伯格平衡檢驗、單位點分析、連鎖不平衡(LD)分析和單倍型構(gòu)建、單倍型分析、統(tǒng)計效力計算分別應用SPSS15.0、Haploview3.2、UNPHASED3.1.3、Epilnfo3.5.1和Quanto1.2.4等軟件進行。 研究結(jié)果如下： 1.在CC2D1A基因中選擇了rs6511898、rs6511901和rs10410239等3個SNP標記,單位點分析結(jié)果表明,這些單個標記位點均與MR沒有關聯(lián)(P0.05)；但由rs6511901和rs10410239所構(gòu)成的單倍型區(qū)域則具有極其顯著的傳遞不平衡(P=0.0009),其中單倍型T-C較多地傳遞給患者(P=0.0238),而T-T則較少被傳遞(P=0.0016)。 2.在CC2D2A基因中選擇了rs7664843、rs1861044、rs10025837、rs13116304和rs7661102等5個SNP標記,單位點分析結(jié)果均為陰性(P0.05)。LD分析表明這5個SNP標記分別構(gòu)成兩個單倍型塊,由rs7664843和rs1861044所組成的單倍型塊Ⅰ與MR無關(P0.05),而由rs10025837、rs13116304和rs7661102構(gòu)成的單倍型塊Ⅱ則與MR顯著相關(P=0.0004),其中單倍型C-C-A更多地傳遞給患者(P=0.0486),而C-C-G較少傳遞(P=0.0026)。以上結(jié)果在經(jīng)過Bonferroni校正后仍具有一定的顯著性。 3.在CRBN基因中選擇了rs711613、s1669322、rs1672761、rs1669336、rs17027638和rs16693426等6個SNP標記,這些標記中僅有rs1669322的單位點分析結(jié)果顯示出相關性(P=0.0371),但在校正后不再具有陽性趨勢。LD分析表明rs1669336、 rs17027638和rs1669342構(gòu)成一個單倍型區(qū)域,該區(qū)域的傳遞與MR表型無關(總P值及各種特殊單倍型的P值均0.05)。 根據(jù)以上結(jié)果,本研究認為CC2D1A、CC2D2A基因與秦巴山區(qū)人群的MR發(fā)病機制之間存在相關性,并且某些特殊的單倍型可能有著易感性或保護作用。CC2D1A基因中呈傳遞不平衡的單倍型塊(rs6511901-rs10410239)與基因的重要功能區(qū)相鄰,可能在該單倍型塊附近有某個與MR患病風險相關且多態(tài)性極低的位點,導致單倍型分析出現(xiàn)顯著的傳遞不平衡；CC2D2A基因的單倍型塊Ⅱ覆蓋了該基因的重要功能區(qū)以及在國外家系中發(fā)現(xiàn)的突變位點,可能在其內(nèi)部也存在一個與MR表型關聯(lián)且變異頻率很低的位點。另外,我們目前也不能排除組成單倍型的各個位點之間存在某種相互作用而對人群易感性產(chǎn)生影響的可能。對于CRBN基因,由于其單位點分析和單倍型分析結(jié)果均為陰性或在校正之后為陰性,因此我們認為該基因與秦巴山區(qū)人群的MR發(fā)病風險之間不存在明顯的相關性。最后,考慮到MR具有很高的遺傳異質(zhì)性,上述所有結(jié)論尚需以更多和更加深入的探索來進行驗證。
[Abstract]:Mental retardation (mental retardation MR) is a kind of common neurological, mental diseases, with mental retardation and lack of ability to adapt to society as the main features, causes of onset before the age of 18 in.MR is more complex, including genetic and environmental factors in two categories, of which about 2/3 cases with the genetic basis of Qin. Ba mountain is one of the regions with a high incidence of MR in China, the prevalence of MR is about 2.70%, the prevalence rate of about 2.78% children, is 2-3 times the national average, bring great burden to the local social economic and cultural development. Therefore, to study the pathogenic mechanism of Qinba mountain MR from the genetic perspective that is an urgent need to continue in-depth meaningful work.
By genetic factors induced by MR with genetic heterogeneity is very high, it has been found that many genes or loci associated with MR patients. Due to males, so long in molecular genetics of the disease mainly focused on the X chromosome, and pairs of autosomes are rarely involved. However, recent studies show that autosomal the gene may play an important role in genetic intelligence or cognitive ability in the investigation of families in the Qinba mountain area also shows that many of the local MR family with autosomal recessive pattern, this paper chose 3 in chromosomal MR candidate genes in the body (CC2D1A, CC2D2A, CRBN) as the research object. To investigate whether there is any correlation between these genes and Qinba Mountain populations of MR.
CC2D1A and CC2D2A gene encoding protein signaling through its C2 domain is involved in the regulation of Ca2+, the influence on neural plasticity and neural development; the protein product of CRBN gene belongs to the ATP dependent Lon protease, can control a plurality of signal pathways in the central nervous system. The research showed that nonspecific MR the mutations in 3 genes lead to some foreign families (that is, in addition to mental retardation and lack of ability to adapt to society, there is no other clinical signs of MR).
In order to avoid the traditional case-control sample accuracy possible population stratification and influence the results, based on the 172 MR nuclear families from Qinba mountain area as a sample, within the 3 genes choose a total of 14 SNP loci as genetic markers for association study. To our knowledge, this is the first the relationship between these 3 genes and MR in random population based on pedigree analysis object of the association. Genotyping by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and PCR- single strand conformation polymorphism (PCR-SSCP) method (with DNA sequencing). Allele frequencies and gene frequency, Hardy Weinberg equilibrium test, unit analysis, linkage disequilibrium (LD) construction, analysis and haplotype analysis, statistical power calculations were used to SPSS15.0, Haploview3.2, UNPHASED3.1.3, Epilnfo3.5.1 and Quanto1.2 .4 and other software.
The results of the study are as follows:
1.鍦–C2D1A鍩哄洜涓，

本文編號：1590885