视网膜色素变性患者视紫红质基因突变分析

目的 研究中国人视网膜色素变性(RP)患者视紫红质(RHO)基因的突变频率及特征,探讨其在RP发病机制中的作用.方法 运用DNA直接测序法,对55例中国内地汉族RP先证者及55例对照者进行RHO全基因突变检测分析.结果 共检出7种碱基变异,其中2种为非致病错义突变,其余5种为非编码区单核苷酸多态性,RP组和对照组各单核苷酸多态性位点突变频率比较,差异均无统计学意义(P＞0.05).结论 RHO基因在中国华南地区RP 患者中的突变率低于国外报道.检出的已报道的单核苷酸多态性位点与RP无显著相关性.     

广东地区视网膜色素变性两大家系RHO基因突变分析

目的 分析广东地区两个常染色体显性遗传视网膜色素变性(autosomal dominant retinitis pigmentosa,ADRP)家系视紫红质（rhodopsin, RHO）基因突变,探讨基因突变与临床表型的关系。 方法 收集广东地区两个常染色体显性遗传视网膜色素变性家系的临床资料,对家系成员进行视力、视野、眼底镜检查;应用聚合酶链反应（PCR）和直接测序技术,对两个家系所有现存成员进行RHO基因检测。 结果 发现一家系患者为P347S杂合性突变,另一家系患者存在P171L杂合性突变,两家系的临床表现为发病早,病情进展快,表型较严重,该两家系正常成员均未发现RHO基因突变。 结论 RHO基因的P347S与P171L突变分别为该两家系视网膜色素变性的病因。该两种突变均导致较严重的临床表型,与分子基础一致。     

常染色体显性遗传视网膜色素变性致病基因Peripherin/RDS的突变筛选

目的：了解中国视网膜色素变性患者（rtinitis pigmentosa,RP)中peripherin/RDS基因的突变谱及突变率。方法：应用聚合酶链-异源双链-单链构象多态性（polymerase chain reaction heteroduplex-single strand conformation polymorphism,PCR-SSCP)及DNA序列分析技术对收集的15个常染色体显性遗传视网膜色素变性家系和55例散发视网膜色素变性病人peripherin/RDS基因的第一、二外显子进行检测。结果：15个家系及55例散发病人未检测到peripherin/RDS基因突变。结论：本研究所检测的视网膜色素变性病人与RDS基因无关。显示视网膜色素变性的遗传异质性。     

视网膜色素变性视紫红质基因突变的检测

近年来，对原发性视网膜色素变性病因和发病机制的研究中发现，视紫红质(rhodopsin，RHO)基因第23、58、347密码子等40余种突变，可引起常染色体显性遗传视网膜色素变性。目前用于RHO基因检测主要是酶切方法。该法所用酶受点突变的严格限制，一种酶只能用=p--种点突变。为此我     

两个家系中X连锁视网膜色素变性的RP2 基因无义突变

目的 检测引起2个家系产生X连锁视网膜色素变性的RP2基因突变。方法 根据RP2基因外显子的内含子DNA序列合成8对引物，以人基因组DNA为模板，PCR扩增出包含RP2基因所有外显子的8个片段。扩增产物化后直接测序。通过比较病人和正常人相应的DNA序列，检测基因突变位点。结果 在2个家系中首次检测到RP2基因的同一个无义突变38C→T。突变位于RP2基因的第2外显子。它使该基因编码精氨酸的遗传密码CGA变为终止密码TGA，引起发病。结论 该突变的检出有助于RP2蛋白的功能分析和X连锁视网膜色素变性的基因诊断。     

RHO基因突变在视网膜色素变性中的分子遗传学分析

目的：探明我国RP患者视紫红质（rhodopsin,RHO)基因突变的特征和意义，方法：在98例RP患者中运用构象敏感凝胶电泳（conformation sensitive gel electrophoresis,CSGE)和DNA直接测序方法检测RHO基因全编码区范围内的点突变。结果：一个ADRP家系的4名患者第347密码子发生点突变，Pro3471Leu;另一个ADRP家系中一名晚发型患者及其目前还未出现症状的女儿在第327密码子出现点突变，Pro327(1－辽),而对照组100例健康成年人未发现上述两种突变，此外在1名患者和2名对照者中还检出一非致病的点突变，Ala299Ser，属单个碱基多态现象（single nucleotide polymophism,SNP）。结论：98例RP先证者中检出2例携带RHO基因突变，由此可初步预测RHO基因在我国RP患者中的突变频率约为2％（95％的可信区间为0．2％－7．0％），Pro347Leu突变改变了视蛋白C末端一段高度保守的氨基酸序列，致使该蛋白在胞内的运输发生障碍，Pro327(1-bp del)使突变蛋白的羧基末端失去了原有的磷酸化位点及上述一段高度保守的功能区，其可能的致病机制有待在今后的研究中通过建立相应的转基因模型或细胞培养系统来阐明。     

视网膜色素变性致病基因研究概况

视网膜色素变性(retinitis pigmentosa,RP)是视网膜光感受器细胞和色素上皮细胞变性导致夜盲和进行性视野缺损的一组具有临床亚型的基因遗传性致盲眼疾病.RP在世界范围内的发病率约为1/3 500~([1]),国内统计发病率为1/3 784,主要临床表现:早期出现夜盲、进行性视野缩小、视网膜骨细胞状色素沉着、视盘呈蜡黄色萎缩和视网膜电图(ERG)呈熄灭型等.其遗传方式为常染色体显性遗传(autosomal dominant retinitis pigmentosa,ADRP)、常染色体隐性遗传(autosomal recessive retinitis pigmentosa,ARRP)、X染色体连锁遗传(X-linked retinitis igmentosa,XLRP)、双基因突变遗传(digenic RP)及线粒体遗传(mitochondrial RP)~([2]),在各类遗传类型中,约15%～25%的患者表现为ADRP,5%～25%的患者表现为ARRP,5%～15%的患者表现为XLRP,40%～50%的患者表现为散发型,双基因突变RP和线粒体RP只占极少数.     

X 连锁隐性遗传视网膜色素变性一家系 RPGR 和RP2基因的突变分析

目的：对1个X连锁视网膜色素变性（ XLRP）家系进行RPGR和RP2基因的突变分析。方法采集该家系11个成员（患者3例,正常人8例）的外周静脉血,提取基因组DNA。应用PCR方法扩增RPGR和RP2基因的全部外显子和内含子交界处序列,包括RPGR基因15号外显子开放阅读框,产物直接测序进行突变分析。结果在RP2发现了1个多态数据库已报道的单核苷酸多态（ SNP）;在RPGR基因中发现了11个SNP,其中3个为已知SNP,8个为本研究首次报道。所有序列变异与疾病表型无共分离现象。结论排除了RPGR和RP2基因突变导致该家系XLRP的可能性。     

ABCA4基因相关的遗传性视网膜变性疾病的表型与基因型分析

目的 在一组ABCA4基因相关的遗传性视网膜变性疾病(hereditary retinal dystrophies,HRD)的无关系先证者中,研究基因型与表型的关系.方法 从2013年1月至2015年7月到第三军医大学西南医院眼科就诊的病例中,选出确诊为ABCA4基因突变的6例无关系先证者,应用眼科裂隙灯检查、视力检查、眼底彩色照相、眼底荧光造影、光学相干断层扫描、电生理检查的方法来分析其表型和基因型的关系.结果 6例无关系的先证者中,3例诊断为Stargardt病(Stargardt disease,STGD),2例诊断为视网膜色素变性(视杆-视锥型,retinitis pigmentosa,RP),1例诊断为视锥细胞营养不良(cone dystrophy,COD).其中,先证者2、6为ABCA4基因的纯合突变,先证者1、3、4、5为ABCA4基因的杂合突变.所有先证者的黄斑中心凹厚度有不同程度变薄,闪光视网膜电图及多焦视网膜电图的各波形也有不同程度的幅值下降及峰时延迟,且临床表现为视网膜色素变性(视杆-视锥型)的患者黄斑区变薄的程度、电生理各波幅值下降程度及峰时延迟程度更显著.结论 ABCA4基因突变可以产生多种临床表型,且同一基因突变方式、同一临床诊断的不同个体病情严重程度有所差异.     

一视网膜色素变性家系的基因检测分析

目的 通过对一个三代视网膜色素变性（RP）家系进行基因检测分析,找到其致病基因.方法 采用外显子捕获直接测序,检测家系成员40个RP相关基因,经与美国国立生物技术信息中心（NCBI）的SNP数据库（dbSNP）和国际人类基因组单体型图（Haplotype Map,简称HapMap）数据库进行比较,查找致病基因.结果 该家系的致病基因位于USH2A基因.该基因编码区存在2个错义突变（p.Tyr1279Asn、p.Cys934Trp）.结论 本研究在一个三代RP家系中发现了USH2A基因p.Tyr1279Asn、p.Cys934Trp两个新突变位点.     

A COMPLETE SCREEN FOR MUTATIONS OF THE RHODOPSIN GENE IN A PANEL OF CHINESE PATIENTS WITH AUTOSOMAL DOMINANT RETINITIS PIGMENTOSA

Objective To evaluate the prevalence of rhodopsin (RHO) mutations and the genotype-phenotype relationships in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) by conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing. Methods We have screened the five coding exons and splice sites of RHO gene in 27 probands who had no relativity from Chinese ADRP families and 100 normal controls to identify disease-associated mutations, using CSGE and direct DNA sequencing. Family members of some probands with disease-associated mutations were also genotyped to determine whether the RHO mutations segregated with retinitis pigmentosa (RP) in their families. Two RHO mutations, Pro347Leu and Pro327 (l-bp del), were identified separately in two families, thus the frequency of RHO mutations among this set of Chinese ADRP families is about 7.4% (2/27). Pro347Leu mutation was found in one ADRP proband as well as three her children who also had RP. She had relatively early onset at about 17 years.The only one child without this mutation had no symptom or sign of RP at age of 34. Pro327 (l-bp del) was identified in a late-onset ADRP patient, who appeared night blindness around 30 years old and in her fifties electroretinogram (ERG) has been fiat in both scotopic and photopic phases. Family analysis showed that this mutation also existed in her younger daughter and her elder sister, both of them also had RP. Three other family members were genotypically and phenotypically normal. Neither of the two mutations was detected in 100 normal controls. Conclusions The frequency of RHO mutations in Chinese patients was lower than that in Europe and North America.The phenotype of the patients with Pro347Leu corresponded to type 1 ADRP, with severe rod degeneration and some cone preservation later, while the phenotype of the patients carrying Pro327 (l-bp del) corresponded to type 2 ADRP, with a concomitant loss of rod and cone visual function. CSGE was found to be a sensitive, simple, and practical method for the screening of a large number of samples under highly reproducible conditions, and could be utilized in routine molecular diagnostic laboratories.     

伴皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病四个家系的NOTCH3基因突变研究

目的 报告4个伴皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病(CADASIL)家系的NOTCH3基因突变特点。方法 对4个经临床和病理检查证实的CADASIL家系中的先证者作NOTCH3基因编码区外显子1～12的聚合酶链反应(PCR)和DNA测序,对家系2和4中的部分亲属也作了同样的检查。结果 4个家系中的先证者均发现有NOTCH3基因的杂合性错义突变,先证者1为外显子3的268C→T突变,先证者2为外显子3的322C→T突变,先证者3为外显子3的328C→T突变,先证者4为外显子11的1819C→T突变,分别造成Notch3蛋白质R90C、C108R、R110C和R607C4个位点氨基酸的替换。其中先证者2的C108R突变尚未见文献报道。在家系2和家系4中,部分成员也携带与先证者同样的突变。结论 这4个家系的CADASIL病均由NOTCH3基因的突变引起,不同位点的基因突变导致相似的临床表现。     

Mass genetics study of rhodopsin point mutations in retinitis pigmentosa

Objective: To evaluate the incidence and pattern of rhodopsin (RHO) mutations in Chinese patients with retinitis pigmentosa (RP). Methods: Conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing were apphed to detect point mutations that occurred in the five coding exons and splice sites of RHO gene in 98 index patients with RP. Results: Four patients of one ADRP family were found to have a missense mutation at codon 347, Pro347Leu. One late-onset RP patient and her daughter, without clinical expression at present, were discovered to have a novel frameshift mutation at codon 327, Pm327 (1-bp del). Neither of the two mutations was found in 100 normal controls. Ma299Ser was found in one RP patient. Two control subjects also had Ma299Ser, suggesting its nonpathogenicity and just single nucleotide polymorphism (SNP). Conclusion: Two RP patients had rhodopsin mutations, thus the expected frequency of RHO mutations in RP is about 2.0% (95% confidence interval: 0.3%-4.4%). A highly conserved C-terminal sequence QVS（A) PA was altered due to Pro347Leu and thereby misdirecting rhodopsin to incorrect subcellular location. Loss of all phosphorylation sites at the C-tenninns and a highly conserved sequence QVS(A) PA may occur because of Pm327(1-bp del). To elucidate the predominant biochemical defects in such mutant, transgenic mice and transfected culture cells carrying Pm327(1-bp del) would be of great value.     

5个遗传性血小板无力症家系的临床表型分析及发病机制研究

目的对5个遗传性血小板无力症（GT）家系进行临床特征分析及基因突变检测,以探索其发病机制。方法通过出血病史、家族史调查,止血和凝血指标检测,血小板聚集实验和流式细胞术检测血小板表面整合素αⅡbβ3表达情况明确5个GT家系的诊断,并用PCR扩增结合直接测序法分析先证者及家系成员的整合素αⅡb基因和β3基因的所有外显子及其侧翼序列,突变位点经检索SNP数据库及查找相关文献排除多态性可能。结果 5个GT家系先证者血小板计数基本正常,凝血象正常,血小板对诱导剂二磷酸腺苷（ADP）反应低下,而对诱导剂瑞斯托霉素反应基本正常;流式细胞术检测结果显示：先证者一为变异型GT,先证者二为Ⅱ型GT,其余3个先证者均为Ⅰ型GT。基因分析共发现1例杂合突变及4例纯合突变：发生在αⅡb基因的4种突变分别为1652C〉T（551Arg〉Gln）、2671C〉T（891Gln〉stop）、2870C〉T（957Ser〉Leu）、2893-2897insC,发生在β3基因的2种突变分别为1199G〉A（400Cys〉Tyr）、1574G〉A（525Gly〉Asp）。结论β3 1199G〉A纯合突变是家系一先证者发生GT的原因;β3 1574G〉A纯合突变是家系二先证者发生GT的原因;αⅡb 1652C〉T纯合突变是家系三先证者发生GT的原因;αⅡb 2671C〉T（891Gln〉stop）纯合突变是家系四先证者发生GT的原因;αⅡb 2870C〉T（957Ser〉Leu）、2893-2897insC双重杂合突是家系五先证者发生GT的原因。其中2671C〉T（891Gln〉stop）、2870C〉T（957Ser〉Leu）和2893-2897insC这3种突变为首次报道发生于αⅡb基因的突变,1574G〉A（525 Gly〉Asp）为首次报道发生于β3基因的突变。     

SCREENING FOR MUTATIONS IN A NOVEL RETIAL—SPECIFIC GENE AMONG CHINESE PATIENTS WITH RETINTITS PIGMENTOSA

Objective.To identify and evaluate mutations in the RP1 gene among Chinese patients with retinitis pigmentosa(RP).Methods.Leukocyte DNA of 92 RP patients were collected in Hong Kong.Sequence changes of the entire coding region of the RP1 gene were examined using PCR,conformation sensitive gel electrophoresis and DNA sequencing.Results.In total,1 nonsense mutation and 1 nonsense variant as well as 10 missense alterations were identified in the RP1 gene,among which,Arg 677 Ter was found in 1 RP patient and another nonsense variant,Arg 1933Ter ,was identified in 3 normal individuals and 1 patient with Stargardt‘s disease,suggesting its nonpatogenicity,Arg667 Ter is expected to lead to large disruptions of the encoded protein.Couclusions.The nonpathogenicity of Arg 1933 Ter indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1.The most C-terminal truncation previously reported was due to Tyr1053(1-bp del) and occurred in RP patients.Thus RP can be caused by reduction in the level of the region of RP1 protein after condon 1052 but before 1933.T o ascertain such a proposition,genotypes of more RP patients may reveal more RP cousative mutations and more sequence alterations different than those of other ethnic groups.     

SCREENING FOR MUTATIONS IN A NOVEL RETINA-SPECIFIC GENE AMONG CHINESE PATIENTS WITH RETINITIS PIGMENTOSA

To identify and evaluate mutations in the RPl gene among Chinese patients with retinitis pigmen-tosa (RP).Methods. Leukocyte DNA of 92 RP patients were collected in Hong Kong. Sequence changes of the entire coding region of the RP1 gene were examined using PCR, conformation sensitive gel electrophoresis and DNA sequencing.Results. In total, 1 nonsense mutation and 1 nonsense variant as well as 10 missense alterations were identified in the RPl gene, among which, Arg677Ter was found in 1 RP patient and another nonsense variant, Argl933Ter, was identified in 3 normal individuals and 1 patient with Stargardt' s disease, suggesting its nonpathogenicity. Arg677Ter is expected to lead to large disruptions of the encoded protein.Conclusions. The nonpathogenicity of Argl933Ter indicates that the C - terminal 224 residues of RPl protein may be not critical for RPl. The most C - terminal truncation previously reported was due to Tyr1053 (1-bp del) and occurred in RP patients. Thus RP can be caused by reduction in     

Analysis of human transforming growth factor β-induced gene mutation in corneal dystrophy

Background Corneal dystrophy is a group of inherited blinding diseases of the cornea. This study was to identify the mutations of the keratoepithelin (KE) gene for proper diagnosis of corneal dystrophy. Methods Three families with corneal dystrophy were analysed. Thirteen individuals at risk for corneal dystrophy in family A, the proband and her son in family B, and the proband in family C were examined after their blood samples were obtained. Mutation screening of human transforming growth factor 15-induced gene (BIGH3 gene) was performed. Results Five individuals in family A were found by clinical evaluation to be affected with granular corneal dystrophy and carried the BIGH3 mutation W555R. However, both probands in families B and C, also diagnosed with granular corneal dystrophy, harboured the BIGH3 mutation R124H. Conclusion Molecular genetic analysis can improve accurate diagnosis of corneal dystrophy.     

常染色体隐性遗传早发性帕金森综合征6型PINK1基因的突变分析

目的探讨常染色体隐性遗传早发性帕金森综合征6型(PARK6)。PINK1基因的突变及临床特征。方法应用聚合酶链反应(PCR)、DNA直接测序和限制性内切酶酶切等技术对11个常染色体隐性遗传早发性帕金森综合征家系先证者进行PINKl基因的突变分析。结果在两个家系中检测出PINK1基因两个新的点突变：位于第4外显子938位的C→T,导致所编码的313位氨基酸由苏氨酸变为蛋氨酸(1313M);位于第7外显子1474位的C→T,导致第492位提前出现终止密码子,截短了后面90个氨基酸。在另一个家系中检测出一个同义突变(Y454Y)。具有PINK1基因突变的患者临床特征包括发病年龄早,病情进展慢,腱反射活跃,症状波动明显,睡眠后症状减轻,对小剂量多巴制剂反应良好,未见到由左旋多巴诱导的运动障碍。结论。PINK1基因突变是常染色体隐性遗传早发性帕金森综合征的常见病因;我国大陆存在PARK6家系;PARK6具有临床异质性。     

中国人早发及多发糖尿病家系中筛查胰岛素启动因子1基因突变

目的 观察中国人早发及多发糖尿病家系胰岛素启动因子1(IPFl)基因的变异情况。方法 采用PCR-SSCP方法筛查154例早发及多发糖尿病家系先证者IPFl基因突变。采用PCR-RFLP方法检测突变家系其他成员及两组正常对照的该突变位点。结果 在多发糖尿病家系先证者中发现1例P239Q错义突变，该家系另有6人携带此突变，且口服葡萄糖耐量试验均在正常范围。P239Q突变未与糖尿病表型共分离。非糖尿病突变携带者餐后2h血糖水平明显高于非突变携带者(P=0．0249)。在“超正常”对照中亦检出1例P239Q突变，中国人糖尿病家系组和正常对照组突变频率分别为0．6％及0．5％。此频率与斯堪的纳维亚人群相似。结论 尽管IPF1基因突变不是中国人早发及多发糖尿病的主要致病基因，但IPF1基因P239Q突变可致轻度糖代谢紊乱，在其他遗传或环境因素的共同作用下参与糖尿病的发生。