马凡综合征两种新的原纤维蛋白-1基因突变

目的对9例马凡综合征(Marfansyndrome,MFS)患者的原纤维蛋白-1(fibrillin-1,FBN1)基因进行突变筛查,以发现新的FBN1基因突变。方法应用变性高效液相色谱法对MFS患者FBN1基因65个外显子中的35个进行突变筛查,对变性高效液相色谱图形异常的PCR扩增片段用DNA测序鉴定突变位置及性质,并用等位基因特异性PCR以及限制性片段长度多态性分析等方法进一步证实突变。结果在两例MFS患者中发现两种新的FBN1基因突变。其中一种为第34外显子4307～4308位4个碱基TCGT的插入突变(4307insTCGT),另一种为第43外显子5309位的点突变5309G>A。结论FBN1基因移码突变(4307insTCGT)与点突变(5309G>A)分别是这两例MFS患者的发病原因。     

Marfan综合征FBN1基因突变研究进展

Marfan综合征是一种常染色体显性单基因遗传性结缔组织病，原纤蛋白基因突变是Marfan综合征的致病原因，本文将从蛋白、基因突变、基因突变与临床表型的关系及突变检测方法四方面概述Marfan综合征的分子生物学研究进展。     

Marfan综合征FBN1基因突变研究进展

Marfan综合征是一种常染色体显性单基因遗传性结缔组织病,原纤蛋白基因突变是Marfan综合征的致病原因,本文将从蛋白、基因突变、基因突变与临床表型的关系及突变检测方法四方面概述Marfan综合征的分子生物学研究进展。     

Marfan综合征和相关微纤维病理研究进展

Marfan综合征 (Marfan syndrom e,MFS)是一种涉及全身结缔组织的常染色体显性遗传性疾病 ,它是由 FBN1 基因突变造成的 ,主要累及眼、骨骼与心血管系统。原纤维蛋白 (fibrillin- 1 ,FBN1 )是 1 0 nm～ 1 2 nm微纤维的主要组成成分 ,FBN1 除了对一些组织有固位作用外 ,还在弹性蛋白的前体与弹性纤维形成的过程中扮演着重要角色。自从发现 FBN1 基因突变以来 ,一直未见有突变热点的报道 ,然而 ,对于那些严重的 Marfan综合征及新生儿患者来说 ,FBN1 基因突变多集中在第 2 3到 32号外显子之间。FBN2基因与 FBN1 基因高度同源 ,FBN2基因突变所造成的表型为先天性挛缩性蜘蛛指 (趾 )征。另外 ,原纤维蛋白 - 1的突变在一些其他相关结缔组织疾病 ,例如单纯晶状体脱位 ,家族性主动脉瘤 ,类 Marfan骨骼畸形中亦被发现 ,因此可以认为 MFS是一系列微纤维病理改变中的一种类型。目前对微纤维球形结构与功能的理论一直不全面 ,本文将全面阐述Marfan综合征与相关微纤维病理改变的分子遗传学研究进展     

Marfan综合征和相关微纤维病理研究进展

Marfan综合征(Marfan syndrome，MFS)是一种涉及全身结缔组织的常染色体显性遗传性疾病，它是由FBN1基因突变造成的，主要累及眼、骨骼与心血管系统。原纤维蛋白(fibrillin-1，FBN1)是10nm～12nm微纤维的主要组成成分，FBNl除了对一些组织有固位作用外，还在弹性蛋白的前体与弹性纤维形成的过程中扮演着重要角色。自从发现FBN1基因突变以来，一直未见有突变热点的报道，然而，对于那些严重的Marfan综合征及新生儿患者来说，FBNl基因突变多集中在第23到32号外显子之间。FBN2基因与FBN1基因高度同源，FBN2基因突变所造成的表型为先天性挛缩性蜘蛛指(趾)征。另外，原纤维蛋白-1的突变在一些其他相关结缔组织疾病，例如单纯晶状体脱位，家族性主动脉瘤，类Marfan骨骼畸形中亦被发现，因此可以认为MFS是一系列微纤维病理改变中的一种类型。目前对微纤维球形结构与功能的理论一直不全面，本文将全面阐述Marfan综合征与相关微纤维病殚改变的分子遗传学研究进展。     

Marfan综合征的基因突变及基因诊断

Marfan综合征是常染色体显性遗传性结缔组织疾病,发病率为0.2‰～0.3‰,病变主要涉及骨骼、眼睛、心血管系统,有时也涉及肺部、皮肤和硬脑脊膜等器官.目前研究认为Marfan综合征发病主要原因为原纤维蛋白基因(fibrillin-1,FBN1)的突变.本文主要介绍了与Marfan综合征相关的FBN1基因及突变特点,重点对目前基因诊断研究情况加以概述.     

Marfan综合征分子遗传学的研究进展

Marfan综合征是一种常染色体显性遗传的结缔组织疾病,主要由原纤蛋白-1(FBN-1)基因突变引起的。目前关于该基因突变导致Marfan综合征机制的研究主要集中在FBN-1基因的多外显子缺失、EGF模序半胱氨酸替代突变、cbEGF模序钙结合点突变、PTC突变、3'末端突变及24-32区突变等方面。本文就此领域作一综述。     

马凡综合征微纤维蛋白1基因突变检测及单倍型连锁分析

目的：检测中国人马凡综合征（Marfan syndrome,MFS)患者微纤维蛋白1（fibillin-1,FBN1)基因的突变及对马凡综合征患者的家系成员进行症状前诊断。方法：应用聚合酶链反应－单链构象多态性技术和测序方法，对汉族9个家系中共17个MFS患者进行基因突变检测；运用FBN1基因内4个内含子中的可变串联重复序列构建染色体单倍型，进行家系单倍型连锁分析和基因诊断。结果：发现MFS（A）家系Ⅱ1患者有单链构象改变，测序证实为位于FBN1基因第25号外显子3243－3256核苷酸之间有I个13bp的小片段缺失，为新位点基因移码突变，其序列为gcctctgcaccca;单倍型连锁分析发现MFS（B）家系Ⅲ1是1个无症状期患者。结论：中国人FBN1基因突变可以引起马凡综合征，应用突变检测与单倍型连锁分析方法能为马凡综合征基因诊断提供依据。     

Marfan综合征分子遗传学研究新进展

Marfan综合征(Marfan syndrome,MFS)是一种常染色体显性遗传性结缔组织病,其病变的微纤维主要牵累3个组织器官系统:骨骼、眼和心血管。1991年,研究发现FBN1突变能导致MFS;2004年,转化生长因子-β受体2(TGFBR2)被认定为MFSⅡ基因;2005年,研究报道TGFBR2突变或TGFBR1突变能够导致一种新的动脉瘤综合征。研究表明,在细胞外基质中,原纤维蛋白-1(fibrillin-1)与转化生长因子β(TGF-β)信号有功能上的相关性。MFS的病理机制可能与TGF-β信号异常有关。     

中国汉族两个马凡综合征家系FBN1基因的一个新突变

目的 对两个常染色体显性遗传的马凡综合征家系进行基因诊断,并探讨其临床特点。方法 完成家系调查和系谱分析,通过聚合酶链式反应和直接测序的方法对收集到的两个家系中的成员进行原纤维蛋白1(fibrillin 1,FBN1)基因的突变检测。结果 两个家系均呈常染色体显性遗传模式。对两个家系成员进行FBN1基因突变检测发现,在两个家系的患者中发现一个相同的突变位点,即FBN1第27号外显子3463位碱基由G变为A( 3463G＞A),导致原纤维蛋白1第1 155位氨基酸由天冬氨酸变为天冬酰胺(Asp 1155Asn),而两个家系的正常成员及选取的100名健康对照中均未发现该突变位点。结论 先证者均符合Ghent标准诊断为马凡综合征,基因诊断发现两家系中相同的突变位点3463G＞A为中国汉族马凡综合征患者中首次报道。     

Comprehensive molecular screening of the FBN1 gene favors locus homogeneity of classical Marfan syndrome

In order to estimate the contribution of mutations at the fibrillin-1 locus (FBN1) to classical Marfan syndrome (MFS) and to study possible phenotypic differences between patients with an FBN1 mutation vs. without, a comprehensive molecular study of the FBN1 gene in a cohort of 93 MFS patients fulfilling the clinical diagnosis of MFS according to the Ghent nosology was performed. The initial mutation screening by CSGE/SSCP allowed identification of an FBN1-mutation in 73 patients. Next, sequencing of all FBN1-exons was performed in 11 mutation-negative patients, while in nine others, DHPLC was used. This allowed identification of seven and five additional mutations, respectively. Southern blot analysis revealed an abnormal hybridization pattern in one more patient. A total of 23 out of the 85 mutations identified here are reported for the first time. Phenotypic comparison of MFS patients with cysteine-involving mutations vs. premature termination mutations revealed significant differences in ocular and skeletal involvement. The phenotype of the eight patients without proven FBN1 mutation did not differ from the others with respect to the presence of major cardiac, ocular, and skeletal manifestations or positive familial history. Most likely, a portion of FBN1-mutations remains undetected because of technical limitations. In conclusion, the involvement of the FBN1-gene could be demonstrated in at least 91% of all MFS patients (85/93), which strongly suggests that this gene is the predominant, if not the sole, locus for MFS.     

Identification of 9 novel FBN1 mutations in German patients with Marfan syndrome

We report 9 new mutations in German patients presenting with classical Marfan syndrome. All mutations occur in exons with calcium‐binding (cb) epidermal growth factor‐like (EGF) domains. Five mutations are missense involving exons 12, 27, 30, 44, and 52 with the resultant substitution of cysteine by phenylalanine (C504F), cysteine by tyrosine (C1129Y), tyrosine by cysteine (Y1261C), cysteine by serine (C1833S), and cysteine by tyrosine (C2142Y), respectively. The other four mutations are single base deletions in exons 39, 43, 48, and 58, at nucleotide A4826, C5311, T6018, and A7291, respectively, each resulting in frameshift with premature termination. Four mutations were detected in sporadic cases and are likely to be de novo. Hum Mutat 14:181, 1999. © 1999 Wiley‐Liss, Inc.     

FBN1 mutation screening of patients with Marfan syndrome and related disorders: detection of 46 novel FBN1 mutations

Fibrillin-1 gene ( FBN1 ) mutations cause Marfan syndrome (MFS), an inherited connective tissue disorder with autosomal dominant transmission. Major clinical manifestations affect cardiovascular and skeletal apparatuses and ocular and central nervous systems. We analyzed FBN1 gene in 99 patients referred to our Center for Marfan Syndrome and Related Disorders (University of Florence, Florence, Italy): 85 were affected by MFS and 14 by other fibrillinopathies type I. We identified mutations in 80 patients. Among the 77 different mutational events, 46 had not been previously reported. They are represented by 49 missense (61%), 1 silent (1%), 13 nonsense (16%), 6 donor splice site mutations (8%), 8 small deletions (10%), and 3 small duplications (4%). The majority of missense mutations were within the calcium-binding epidermal growth factor-like domains. We found preferential associations between The Cys-missense mutations and ectopia lentis and premature termination codon mutations and skeletal manifestations. In contrast to what reported in literature, the cardiovascular system is severely affected also in patients carrying mutations in exons 1–10 and 59–65. In conclusion, we were able to detect FBN1 mutations in 88% of patients with MFS and in 36% of patients with other fibrillinopathies type I, confirming that FBN1 mutations are good predictors of classic MFS.     

FBN1新生突变引起的马凡综合征及其基因型-表型的关联研究

 目的: 本研究对2个不同马凡综合征(Marfan syndrome)的小家系进行致病基因FBN1的编码区和剪切位点突变检测,以寻找致病的突变,并初步探索马凡综合征基因型-表型的关联。方法: 通过临床检查、实验室检查及心脏超声检查确诊2个无血缘关系的家庭中原疑似为马凡综合征的3例患者。运用新一代测序对家系1的疑似患者行FBN1基因的全外显子组测序,并对检出的致病性遗传变异进行Sanger验证及在所有家系成员中验证;对于家系2的存活成员,本研究直接进行PCR扩增FBN1基因的所有编码区及剪切位点,对产物进行直接Sanger测序。另外在50个正常对照中对新发现的突变位点进行基于PCR产物的测序分析,以排除多态性;并对实验结果行生物信息学分析。结果: 所有存活的疑似患者均确诊为马凡综合征。在家系1中,我们检测到了一个FBN1基因数据库中尚未报道的新突变c.4685G>A(p.Cys1562Tyr),并且患者父母和同胞姐姐均未检测到此变异,故此突变为一个新生突变。该错义突变使第1562位上极性中性的含硫的半胱氨酸被极性中性的含羟苯基的酪氨酸所替代,影响了fibrillin-1蛋白一个TGF-β结合结构域,导致蛋白质的二级结构发生改变。家系2含父母及一对同卵双胎患者,其中一患者已去世。我们在存活患者检测到1个FBN1基因的已报道致病突变c.3706T>C(p.Cys1236Arg),该突变在患者父母中不存在,故也为新生突变。结论: 本文报道了一例FBN1基因的新突变及另一例由FBN1基因已知突变引起的马凡综合征,二者皆为新生突变,并在家系中进行了基因型-表型的比较,表明家系1的新突变可能与经典马凡综合征的表型相关,而家系2的已知突变确和新生儿重症马凡综合征表型相关。     

Mutation screening of all 65 exons of the fibrillin-1 gene in 60 patients with Marfan syndrome: Report of 12 novel mutations

Mutations in the fibrillin-1 gene on chromosome 15q21.1 have been found to cause Marfan syndrome, a dominantly inherited disorder characterised by clinically variable skeletal, ocular, and cardiovascular abnormalities. In this study we screened all 65 exons of the fibrillin-1 gene in 20 Marfan syndrome families where at least two affected individuals were characterised and available for analysis, another 30 families with only one affected member available for analysis, and in 10 sporadic cases. In large well-characterised families with more than four affected individuals, the detection rate for mutations rose to 78% (7/9), in families with either two or three affected members 27% (3/11). In families where only one affected family member was available, the mutation detection rate was 17% (5/30), and in sporadic cases it was 20% (2/10). In addition, we found eight neutral polymorphisms. Twelve of the 17 disease-causing mutations identified have not been previously described, thus raising the total number of different fibrillin-1 mutations reported to 85 in 94 unrelated cases. Hum Mutat 10:280–289, 1997. © 1997 Wiley-Liss, Inc.     

Identification of 29 novel and nine recurrent fibrillin-1 (FBN1) mutations and genotype-phenotype correlations in 76 patients with Marfan syndrome

Marfan syndrome (MFS) is an autosomal-dominant disorder of the fibrous connective tissue that is typically caused by mutations in the gene coding for fibrillin-1 (FBN1), a major component of extracellular microfibrils. The clinical spectrum of MFS is highly variable and includes involvement of the cardiovascular, skeletal, ocular, and other organ systems; however, the genotype-phenotype correlations have not been well developed. Various screening methods have led to the identification of about 600 different mutations (FBN1-UMD database; www.umd.be). In this study we performed SSCP and/or direct sequencing to analyze all 65 exons of the FBN1 gene in 116 patients presenting with classic MFS or related phenotypes. Twenty-nine novel and nine recurrent mutations were identified in 38 of the analyzed patients. The mutations comprised 18 missense (47%), eight nonsense (21%), and five splice site (13%) mutations. Seven further mutations (18%) resulted from deletion, insertion, or duplication events, six of which led to a frameshift and subsequent premature termination. Additionally, we describe new polymorphisms and sequence variants. On the basis of the data presented here and in a previous study, we were able to establish highly significant correlations between the FBN1 mutation type and the MFS phenotype in a group of 76 mutation-positive patients for whom comprehensive clinical data were available. Most strikingly, there was a significantly lower incidence of ectopia lentis in patients who carried a mutation that led to a premature termination codon (PTC) or a missense mutation without cysteine involvement in FBN1, as compared to patients whose mutations involved a cysteine substitution or splice site alteration.