中国南方先天性白内障一家系GJA8基因C>G新突变

目的 对一个常染色体显性遗传先天性白内障（ADCC）家系进行候选基因筛查,以期寻找其可能的致病基因。设计 实验研究。研究对象 一个中国南方ADCC家系。方法 应用聚合酶链反应（PCR）和DNA直接测序方法,对该家系进行ADCC常见致病基因突变筛查。主要指标 基因序列。结果 临床眼科检查显示该家系先天性白内障类型为核性白内障。候选基因序列测定显示在GJA8基因c.565位置上存在C>G的突变,该突变导致在缝隙连接蛋白Cx50 p.189位置上的脯氨酸突变为丙氨酸,此氨基酸改变位点位于缝隙连接蛋白结构中第二个细胞外段。而该家系中非患者和100名对照者基因组序列均无此改变。结论 位于GJA8 的c.565C>G突变是导致此先天性白内障家系可能的致病原因,缝隙连接蛋白第二个胞外结构域对晶状体的透明性起着重要作用。（眼科, 2013, 22: 86-89）     

一个CRYAA基因突变先天性白内障家系

目的研究一个四代常染色体隐性遗传性先天性白内障家系的致病基因。方法调查研究。采集一个先天性白内障家系中3例患者和1例表型正常者的外周静脉血各5 ml,收集100例正常人外周静脉血各5 ml作为对照,提取所有参与者基因组DNA。选择与先天性白内障发生相关的八个致病基因（CRYAA、CRYAB、CRYBA1、CRYGC、CRYGD、CRYGS、GJA3、GJA8）作为候选基因,进行聚合酶链反应扩增候选基因的外显子及毗邻内含子。扩增产物进行直接测序,测序结果与GeneBank中序列进行BLAST比对分析,寻找突变位点。结果该家系中先证者及患者均在CRYAA基因第1外显子发生c.160 C>T杂合突变,导致其编码的晶状体蛋白第54位精氨酸变为半胱氨酸（p.R54C）。该家系中参与研究的1名表型正常者和100名正常对照者无此基因突变。结论CRYAA基因 c.160 C>T（p.R54C）突变是导致该先天性白内障家系致病的主要原因。     

先天性无虹膜合并先天性白内障家系致病基因突变分析

目的：对先天性无虹膜合并先天性白内障家系进行PAX6基因突变位点筛查,丰富该致病基因的突变谱。

方法：选取就诊于北京同仁医院眼科门诊的1个先天性无虹膜合并先天性白内障家系和100名健康志愿者,采集外周静脉血,提取基因组DNA,采用直接测序法进行PAX6基因突变位点的筛查。

结果：该家系中先证者和其他患者均表现为无虹膜合并白内障,PAX6基因测序结果显示,该致病基因第11外显子无义突变c.991 C>T,造成PAX6基因编码的蛋白截短(R331X),从而使该蛋白失去功能,且该突变在家系内与疾病表型共分离,不存在于家系内及家系外健康样本的基因中。

结论：PAX6 R331X突变与先天性无虹膜合并先天性白内障的发生有关。     

一先天性无虹膜家系PAX6基因遗传筛查及临床表型

目的探讨我国常染色体显性遗传先天性无虹膜一家系患者的致病基因突变位点及其临床表型。方法实验研究。于南京医科大学第一附属医院眼科收集一先天性无虹膜家系,共8名家庭成员,其中3名患者,2名正常同胞,3名配偶。完善该家系内所有参与者的眼科检查,采集该家系成员的外周静脉血,提取基因组DNA,扩增PAX6基因的全部编码区及外显子-内含子交界区剪切位点附近的序列,直接测序法确定该家系的致病突变。结果遗传学筛查结果证实该家系的致病突变为位于PAX6基因第7号外显子与第7号内含子交接处的杂合突变（c.357+5G>A）。生物信息学分析结果表明该突变可导致正常剪切位点的缺失,产生移码突变,形成截短蛋白p.Ser121Asnfs*30。该家系中3例患者均表现出典型的先天性无虹膜症的临床表型,表现为虹膜发育不全,与此同时,该家系内患者还具有上睑下垂、白内障、眼球震颤、青光眼及玻璃体混浊等眼部异常。结论PAX6 c.357+5G>A杂合突变为该家系的致病突变,是该家系发生先天性无虹膜及上睑下垂、白内障、眼球震颤、青光眼及玻璃体混浊等一系列临床表型的主要致病原因。     

中国北方一先天性白内障家系GJA8基因新突变

目的　对一个中国先天性白内障家系进行分子遗传学研究，并分析其基因型与表型相关性。方法　对该家系采集详细的病历资料，并进行全面的眼科检查，采集外周血并提取DNA。用二代测序方法对可能致病基因进行测序，对发现的变异通过Sanger测序法进行DNA序列分析。结果　在先证者的GJA8基因第二外显子中发现了一个杂合错义突变［c.199G>T］(p.Asp67Tyr)，这一突变也存在于该家系的其他白内障成员中，在正常亲属中未发现相同改变。该家系先证者IV2表现为双眼晶状体全白色混浊，其母III3表现为双眼点状晶状体混浊。结论　在一个中国先天性白内障家系中，发现GJA8基因新致病突变（c.199G>T），拓宽了GJA8基因的突变谱，有助于加深对先天性白内障发病机制的认识。     

应用外显子结合目标区域捕获测序芯片对一回族先天性白内障家系致病基因的检测

背景 先天性白内障是造成儿童盲和弱视的重要原因,其中约50％的先天性白内障具有遗传性.目的 应用眼遗传病外显子结合目标区域捕获测序芯片检测一常染色体显性遗传先天性白内障家系的致病基因.方法 于2011年在宁夏眼科医院收集一回族常染色体显性遗传先天性白内障家系,采集家系中患者及表型正常成员的临床资料.对家系成员进行眼科检查,抽取患者、表型正常家系成员及300名正常对照者的外周静脉血各5 ml,提取DNA,利用眼遗传病外显子结合目标区域捕获测序芯片筛查和检测候选致病突变位点.采用PCR和直接测序法对家系成员和正常对照者进行突变位点验证,最终确定致病突变位点.结果 该家系共6代61名成员,均为回族,先天性白内障患者18例,为5代遗传,符合常染色体显性遗传特征.患者中合并眼球震颤和斜视者7例,合并高度近视者4例,来诊前均已实施白内障摘出术.利用眼遗传病外显子结合目标区域捕获测序芯片检测结合生物信息学方法筛查后共得到8个候选致病突变位点,其中5个在非编码区,3个在编码区,通过PCR和直接测序法验证确定CRYGD基因上的P24T突变是该家系的致病突变位点.该突变与家系内所有患者表型共分离,在家系表型正常者及300名正常对照者均未发现此突变.结论 外显子结合目标区域捕获测序技术快速检测CRYGD基因P24T突变为该先天性白内障家系致病突变,该技术为临床表型多样、致病基因众多的先天性白内障的致病基因检测提供新的手段.     

一个 FBN1基因突变的先天性单纯性晶状体异位家系的分析

目的分析一个晶状体异位家系的临床特征及致病基因,并探讨基因突变与其临床表型间的关系。 方法2018年8月收集晶状体异位家系的临床资料,绘制家系系谱图。采集家系成员的外周静脉血,提取基因组脱氧核糖核酸,应用靶向基因测序方法初步筛选该家系候选突变基因,采用Sanger测序验证和家系共分离分析,确定该家系的致病基因及其突变位点。 结果该家系成员共有两代4人。其中,先证者Ⅱ1及其患病母亲分别于6岁及17岁时确诊为双眼晶状体异位,无骨骼系统及心血管系统等异常;先证者Ⅱ1及其患病母亲携带FBN1基因c.1600T>A (p.C534S)杂合突变,生物信息学分析提示具有高致病性,符合家系共分离特征。 结论该家系符合先天性单纯性晶状体异位疾病特征;FBN1基因c.1600T>A (p.C534S)是该家系的致病突变,为常染色体显性遗传;该位点突变导致第534号氨基酸由半胱氨酸变异为丝氨酸,此为人群中的首次报道。     

RPGRIP1基因新突变致Leber先天性黑矇一家系

目的确定1个汉族Leber先天性黑矇(LCA)家系的致病基因突变。方法回顾性研究。2018年10月在河南省立眼科医院就诊的LCA一家系1例患者和3名家系成员纳入研究。详细询问患者病史并行物体注视性质、追随试验、裂隙灯显微镜、散瞳验光、眼底照相及全视野ERG检查;家系成员行BCVA、裂隙灯显微镜联合前置镜、验光、眼底照相及全视野ERG检查。采集先证者及其兄长、父母的外周静脉血5 ml,提取全基因组DNA。应用包含441个致病基因的遗传眼病捕获芯片进行靶向捕获富集高通量测序以获得致病基因及突变。对可疑致病突变位点通过Sanger进行验证,并行生物信息学分析确定基因突变位点的致病性。结果患者表现为自幼不追物但有明显畏光和眼球震颤;双眼眼前节及眼底无异常;全视野ERG检查可见双眼视锥、视杆系统功能严重下降。基因检测结果显示,患者RPGRIP1基因存在c.1635dupA和c.3565C>T两个突变。其中,RPGRIP1 c.1635dupA为新发突变。RPGRIP1基因c.1635dupA和c.3565C>T构成复合杂合突变。生物信息学分析结果显示,c.3565C>T为致病突变,c.1635dupA为可能致病突变。结论RPGRIP1基因新发突变c.1635dupA与c.3565C>T构成复合杂合突变可能是本家系的致病原因。     

先天性无虹膜家系中发现PAX6基因新的致病突变

目的对中国一先天性无虹膜家系进行PAX6基因突变检测,以确定其突变位点。方法实验研究。收集一先天性无虹膜家系,采集该家系患者及健康成员的外周静脉血,收集100名健康人外周血作为正常对照,采用Sanger测序的方法对PAX6基因的11个外显子（外显子4-14）以及外显子-内含子连接区域进行测序,随后进行家系共分离分析以及正常样本的对照分析。结果该家系8名成员经全面眼科检查,3名确诊为先天性无虹膜,且合并有复杂的眼部表型,包括不同程度的角膜病变、不同类型的白内障、黄斑发育不良、轻度上睑下垂和轻度眼球水平震颤等。在该家系患者中发现一个新杂合突变[c.569_570delinsACGG（p.Ile190Asnfs*18）],该突变可致PAX6基因编码的蛋白截短,该突变符合共分离且在100名正常对照者中未检测到。结论PAX6基因第8外显子上一个新的杂合突变[c.569_570delinsACGG（p.Ile190Asnfs*18）]为本研究中先天性无虹膜家系的致病突变,该突变与先天性无虹膜有关,本研究扩大了PAX6基因的突变频谱。     

一个后极性白内障家系致病基因的筛查与鉴定

目的　对中国一个具有常染色体显性遗传特点的后极性白内障家系进行致病基因的筛查。方法　分别采集家系成员外周静脉血,提取基因组ＤＮＡ,根据临床表型选取６个候选基因（ＣＲＹＡＡ、ＣＲＹＡＢ、ＰＩＴＸ３、ＣＨＭＰ４Ｂ、ＭＩＰ、ＣＲＹＧＤ）设计引物,通过ＰＣＲ扩增ＤＮＡ片段,琼脂糖凝胶电泳分离ＤＮＡ片段,直接测序法寻找致病基因及突变位点。结果　该家系符合常染色体显性遗传家系特征,先证者表型为后极性白内障,通过候选基因外显子直接测序,发现家系内患者ＣＲＹＧＤ基因第２个外显子第１２７位碱基有１个Ｔ→Ｃ的点突变,此突变导致蛋白第４３位的色氨酸被精氨酸取代（Ｗ４３Ｒ）。结论　ＣＲＹＧＤ基因ｃ．Ｔ１２７Ｃ（ｐ．Ｗ４３Ｒ）突变是该后极性白内障家系的致病原因。     

珊瑚状先天性白内障一家系致病基因筛查与鉴定

目的：对一个珊瑚状先天性白内障家系进行致病基因的筛查。方法：采集家系中2例患者和1例正常对照者的外周静脉血,提取基因组DNA。选择与珊瑚状白内障相关的候选基因GJA3、GJA8、CRYGC及CRYGD设计引物,进行聚合酶链反应（ PCR）扩增候选基因,并对扩增片段进行Sanger测序。结果：该家系疾病表型为珊瑚状白内障,呈常染色体显性遗传。通过对扩增产物测序,发现家系内患者CRYGD第2个外显子第70位有1个C＞A碱基的杂合突变（ c．70C＞A）,正常对照未见该点突变。结论：CRYGD基因的错义突变c．70C＞A是该珊瑚状白内障家系的致病原因。     

Identification of a CRYAB mutation associated with autosomal dominant posterior polar cataract in a Chinese family

PURPOSE: A four-generation Chinese family with 13 members affected with autosomal dominant congenital posterior polar cataract was studied. The purpose of this study was to identify the disease-causing gene in the family and to validate that mutations in CRYAB, the alphaB-crystallin gene, cause the congenital cataract. METHODS: Linkage analysis was performed with a panel of microsatellite markers flanking candidate genetic loci for cataracts, including 14 known autosomal dominant congenital cataract (ADCC) genes. For mutation analysis, the complete coding region and exon-intron boundaries of CRYAB were sequenced with DNA from the proband. Single-strand conformation polymorphism (SSCP) analysis for exon 1 of CRYAB was performed in all family members and 200 normal control subjects. RESULTS: The disease gene in the Chinese family was mapped to chromosome 11 in region q22-22.3 with a maximum lod score of 4.52. Direct DNA sequence of CRYAB revealed a heterozygous C-->T transition at nucleotide 58, resulting in a novel 58 C-->T (Pro20Ser) mutation. The Pro20Ser mutation cosegregated with all affected individuals and was not present in unaffected members in the family or in 200 normal control subjects. The mutation occurs at the evolutionarily conserved residue Pro20 in the N-terminal region of alphaB-crystallin. CONCLUSIONS: To date, only one CRYAB mutation has been associated with congenital isolated cataract. This study identified a second novel mutation in CRYAB in a large Chinese cataract family. Together, these results provide strong evidence that CRYAB is a pathogenic gene for congenital cataract.     

A novel Nance-Horan syndrome mutation identified by next-generation sequencing in a Chinese family

AIM: To identify the disease-causing mutation in a four-generation Chinese family diagnosed with Nance-Horan syndrome (NHS). METHODS: A Chinese family, including four affected patients and four healthy siblings, was recruited. All family members received ophthalmic examinations with medical histories provided. Targeted next-generation sequencing approach was conducted on the two affected males to screen for their disease-causing mutations. RESULTS: Two male family members diagnosed with NHS manifested bilateral congenital cataracts microcornea, strabismus and subtle facial and dental abnormalities, while female carriers presented posterior Y-sutural cataracts. A novel frameshift mutation (c.3916_3919del) in the NHS gene was identified. This deletion was predicted to alter the reading frame and generate a premature termination codon after a new reading frame. CONCLUSION: The study discovers a new frameshift mutation in a Chinese family with NHS. The findings broaden the spectrum of NHS mutations that can cause NHS in Chinese patients.     

Truncating mutation in the NHS gene: phenotypic heterogeneity of Nance-Horan syndrome in an asian Indian family

PURPOSE: A four-generation family containing eight affected males who inherited X-linked developmental lens opacity and microcornea was studied. Some members in the family had mild to moderate nonocular clinical features suggestive of Nance-Horan syndrome. The purpose of the study was to map genetically the gene in the large 57-live-member Asian-Indian pedigree. METHODS: PCR-based genotyping was performed on the X-chromosome, by using fluorescent microsatellite markers (10-cM intervals). Parametric linkage analysis was performed by using two disease models, assuming either recessive or dominant X-linked transmission by the MLINK/ILINK and FASTLINK (version 4.1P) programs (http:www.hgmp.mrc.ac.uk/; provided in the public domain by the Human Genome Mapping Project Resources Centre, Cambridge, UK). The NHS gene at the linked region was screened for mutation. RESULTS: By fine mapping, the disease gene was localized to Xp22.13. Multipoint analysis placed the peak LOD of 4.46 at DSX987. The NHS gene mapped to this region. Mutational screening in all the affected males and carrier females (heterozygous form) revealed a truncating mutation 115C-->T in exon 1, resulting in conversion of glutamine to stop codon (Q39X), but was not observed in unaffected individuals and control subjects. conclusions. A family with X-linked Nance-Horan syndrome had severe ocular, but mild to moderate nonocular, features. The clinical phenotype of the truncating mutation (Q39X) in the NHS gene suggests allelic heterogeneity at the NHS locus or the presence of modifier genes. X-linked families with cataract should be carefully examined for both ocular and nonocular features, to exclude Nance-Horan syndrome. RT-PCR analysis did not suggest nonsense-mediated mRNA decay as the possible mechanism for clinical heterogeneity.     

一常染色体显性遗传性白内障家系致病基因的排除性定位

目的对常染色体显性遗传先天性白内障家系进行致病基因的定位研究。方法对4代11例家系成员（6例患者）进行眼部和全身检查,采集静脉血,提取基因组DNA,选取已报道的与遗传性白内障相关位点附近的微卫星标记,PCR扩增后进行基因型分析,用连锁分析进行排除;没有排除的位点,基因外显子测序。结果 35例家系成员中,追溯调查共有10例患者,其中第1代1例,第2代2例,第3代5例,第4代2例。该家系患者表型为完全性白内障;绝大多数位点,患者没有共享基因型;微卫星标记与致病基因间的2点连锁Lod值〈-2,证实这些位点与该家系的致病基因不连锁;有3个多态性标记（D10S1239、D22S286、D22S926）0〈Lod值≤0.6,Lod值虽然不是〈-2,但在家系患者中没有共享等位基因;测序未发现外显子有突变。结论此家系的致病基因不是已报道位点的致病基因,其致病基因有待进一步研究。     

Refinement of the X-linked cataract locus (CXN) and gene analysis for CXN and Nance-Horan syndrome (NHS)

The X-linked congenital cataract (CXN) locus has been mapped to a 3-cM (approximately 3.5 Mb) interval on chromosome Xp22.13, which is syntenic to the mouse cataract disease locus Xcat and encompasses the recently refined Nance-Horan syndrome (NHS) locus. A positional cloning strategy has been adopted to identify the causative gene. In an attempt to refine the CXN locus, seven microsatellites were analysed within 21 individuals of a CXN family. Haplotypes were reconstructed confirming disease segregation with markers on Xp22.13. In addition, a proximal cross-over was observed between markers S3 and S4, thereby refining the CXN disease interval by approximately 400 Kb to 3.2 Mb, flanked by markers DXS9902 and S4. Two known genes (RAI2 and RBBP7) and a novel gene (TL1) were screened for mutations within an affected male from the CXN family and an NHS family by direct sequencing of coding exons and intron- exon splice sites. No mutations or polymorphisms were identified, therefore excluding them as disease-causative in CXN and NHS. In conclusion, the CXN locus has been successfully refined and excludes PPEF1 as a candidate gene. A further three candidates were excluded based on sequence analysis. Future positional cloning efforts will focus on the region of overlap between CXN, Xcat, and NHS.