常染色体显性先天性绕核性白内障临床遗传学研究

目的了解先天性绕核性白内障家族遗传特征和细胞遗传学特点。方法对４个常染色体显性遗传家系及其先证者进行系谱和染色体核型分析。结果先天性绕核性白内障遗传属质量性状，为单基因遗传病；该病发病：患病／未患病＝１１／１０；男／女＝７／４；表现为连续传递，且以完全显性遗传为主；少数家系表现为不规则显性遗传，外显率为１１／１６（６８７５％）；该型白内障核型组成：４４＋ＸＹ（ＸＸ），第１号染色体相对长度和着丝粒指数低于正常，臂比高于正常。结论先天性绕核性白内障临床遗传以常染色体显性为主，其形成有特定的细胞遗传学基础。     

晶状体蛋白βB2基因突变导致常染色体显性遗传先天性白内障

目的定位常染色体显性遗传先天性粉尘状核性白内障一家系的致病基因。方法收集该家系资料,针对与常染色体显性遗传先天性白内障发病相关的14个热点致病基因设计引物,对此4代先天性白内障家系进行热点突变位点的分析,了解是否有相应的改变。结果此家系患者编码人类晶状体蛋白的基因βB2的第6外显子存在一个C→T突变,此突变导致终止密码子提前出现。该基因的第2外显子的第40个核苷酸存在A/T的单核苷酸多态性。结论编码人类晶状体蛋白的基因βB2是此先天性白内障家系的致病基因。     

先天性后极性白内障超微结构分析及突变基因筛查

目的 探讨一先天性后极性白内障家系晶状体的超微结构改变,并初步筛查其致病基因.方法 收集一常染色体显性遗传性先天性后极性白内障家系资料,对家系成员行眼部检查;在透射电镜下观察晶状体细胞超微结构的改变;选择CRYAB、CRYBA1/A3、CRYBB2、GJA8、CHMP4B、PITX3和EPHA2这7个热点基因进行突变位点筛查.结果 根据家系图分析该家系为垂直遗传,符合单基因常染色体显性遗传特点.裂隙灯显微镜下检查示全部患者晶状体混浊形态完全相同.透射电镜下发现患者前囊面晶状体上皮细胞排列紧密,结构完整,未见特异性病理变化;前皮质晶状体纤维细胞排列紧密,细胞内密度均一一致,但后皮质晶状体纤维细胞内出现斑驳状中高密度异常颗粒沉着.热点基因筛查显示:7个候选基因的外显子及其邻近内含子序列与基因库对照未发现任何突变.结论 本研究将后极性白内障病变定位于后皮质晶状体纤维细胞,排除了前囊面晶状体上皮细胞及前皮质晶状体纤维细胞.此家系携带的遗传突变位点位于尚未见报道的与后极性白内障相关的致病基因上.     

常染色体显性遗传性白内障家系的临床遗传学分析

目的进一步确定目前常见的常染色体显性遗传性白内障不同的临床表型，评价不同家系之间和家系内不同个体之间先天性白内障障表型的变异。方法收集东北地区常染色体显性遗传性白内障大家系。所有患病个体经眼科及全身检查，除外眼外其它疾患。结果共收集先天性遗传性白内障大家系六个，203人，其中61人患病。形态学上分别表现为核性、圆盘状、板层、粉尘状。结论常染色体显性遗传性白内障不同基因可有相同的临床表型，在不同家系间表型有不同．同一家系中不同个体间也有不同。这进一步揭示了基因的遗传异质性、变异性。     

HSF4基因突变导致常染色体显性遗传核性白内障

目的 鉴定一个延续5代常染色体显性遗传核性白内障家系的致病基因。方法 根据已知先天性白内障致病基因在染色体上的定位，选择了D16S539分子标记，对该家系进行连锁分析，通过基因测序鉴定致病基因。结果 该69名家系成员中有16例患有先天性核性白内障，致病基因定位于16q21-q22，并在候选基因HSF4外显子3检测到一新的突变杂合子134456G-A，该突变导致112E的同义突变，而在家系正常成员中则未检测到该突变。结论 该家系核性白内障表型很可能系由HSF4基因134456G-A突变所致，且此突变尚未见报道。     

遗传性先天性核性白内障家系CRYAB错义突变

目的 鉴定一个四代常染色体显性遗传性先天性白内障(autosomaldominant congenital cataract,ADCC)家系的致病基因.方法 收集ADCC一家系资料,全面检查,提取血液DNA,在已报道的与先天性白内障相关的致病基因和其附近选择合适的微卫星标记位点进行连锁分析,对提示连锁的染色体区域内的已知候选基因测序.结果 系谱图分析示该ADCC家系符合常染色体显性遗传特点.裂隙灯显微镜检查示全部患者表型均为核性.连锁分析示致病基因定位在11q22.3-23.1区域内,对此区域内的候选基因B-晶状体蛋白基因进行测序,发现其外显子1第58位核苷酸C→T错义突变,引起所编码的第20位脯氨酸被丝氨酸取代(p20S).结论 B-晶状体蛋白的点突变导致了该家系遗传性先天性核性白内障,丰富了基因型-表型谱,并为分子机制的研究提供了新线索.     

染色体核型正常的先天性白内障家系

目的了解先天性白内障与遗传因素的关系。方法对来自４个不同家系的先天性白内障患者３６例（７２眼），进行细胞遗传学检测、家系调查及眼科检查。结果４个先天性白内障家系的遗传方式为常染色体显性遗传，１５例患者的染色体核型正常，３６例患者的晶体混浊形态和部位各异。结论先天性白内障是一组具有遗传和临床异质性的晶体病。     

先天性白内障一家系的致病基因初步筛查

目的：对常染色体显性遗传先天性白内障一家系的致病基因进行初步筛查。方法收集常染色显性遗传的白内障一家系23名成员的外周静脉血,提取基因组DNA,选取与已知常染色体显性遗传的先天性白内障的候选基因CRYGD、GJA3,采用软件Linkage对该家系2个基因附近共10个STR位点进行两点法连锁分析,筛查这2个基因是否为此家系的致病基因。结果对该家系的基因连锁分析表明,基因CRYGD、JGA3所有编码区及外显子与内含子交界处均未发现基因序列的突变。结论基因CRYGD、GJA3不是该家系的遗传致病基因,对该家系需进一步做全基因组扫描,以发现致病基因在染色体上的可疑区间。     

先天性白内障一家系致病基因的排除性定位

目的 明确一个国人常染色体显性先天性白内障（ADCC）家系致病基因的染色体位点是否位于已知的22个非综合征型ADCC致病位点内，从而初步定位该ADCC家系致病基因的染色体位点。设计 家系遗传研究。研究对象 一个先天性白内障家系。方法 对26例家系成员中的16例进行临床检查、采集静脉血样、提取基因组DNA；在已知的22个非综合征型ADCC致病位点内，分别选取3-6个多态性微卫星标记，对该ADCC家系进行遗传连锁分析。主要指标 先天性白内障临床表型、Lod值。结果 该家系患者为晶状体前囊膜及前囊膜下混浊；所有多态性微卫星标记与致病基因两点间的Lod值均≤-2，证实微卫星标记所在的染色体区域与该ADCC家系的致病基因不连锁。结论 该ADCC家系致病基因的染色体位点不在已知的22个非综合征型ADCC致病位点内，可能是一个新的致病基因导致了该家系的临床表型。     

晶状体蛋白βB1基因错义突变引起常染色体显性遗传性白内障

目的 对河北汉族一个四代先天性核性常染色体显性遗传白内障家系进行基因分析,了解此家系在候选基因上是否存在突变位点.方法 该家系22名成员(包括患者7人,非患者15人)知情同意进入本研究,并接受全面的眼部及全身检查,以排除白内障以及外眼部及全身疾患.该家系成员中患病者经眼部裂隙灯检查发现晶状体均为核性混浊.采集22名家系成员的外周静脉血,提取基因组DNA.选择国内外已报道的与先天性核性白内障发生相关的7个候选基因(CRYBA3/A1、CRYBB1、CRYBB2、CRYGD、GJA3、CJA8和MIP),设计引物使聚合酶链反应扩增的片段覆盖候选基因外显子,对扩增产物进行测序和序列分析,寻找突变位点.结果 发现编码晶状体蛋白Bb1的基因(CRTBB1)第4外显子一个等位基因的第457个碱基发生错义突变C＞A.形成杂合子,导致其编码蛋白第129位氨基酸由丝氨酸(S)转变为精氨酸(R),其余外显子的碱基序列与GenBank数据库中的正常序列一致.结论 该家系的核性先天性白内障是由于CRYBB1基因外显子4的错义突变C＞A引起.     

一特殊表型的常染色体显性遗传先天性白内障家系致病基因的筛选与鉴定

背景遗传因素是先天性白内障的主要致病因素之一,致病基因的筛查是研究先天性白内障发病分子机制的重要步骤。目的明确一结晶样晶状体混浊的先天性常染色体显性遗传白内障（ADCC）家系的致病基因。方法收集山西省榆社县一个四代先天性结晶样混浊白内障家系22名成员,其中患者10例。在获得知情同意后,该家系成员进行家系调查以确定遗传方式。经裂隙灯显微镜检查和常规眼科临床检查确定表型。采集其中17例家系成员的外周静脉血5ml并提取DNA,ADCC的17个已知致病基因周围选取22个荧光标记的微卫星,通过对微卫星标志物的扩增和基因型分析对该家系进行基因两点连锁分析,并计算对数优势评分（LOD）值。对筛选的候选基因进行直接测序分析。结果该家系患者晶状体混浊表型非常类似,家系分析表明为四代垂直遗传,符合单基因ADCC的特点。基因连锁分析提示,该家系与微卫星D2S325位点和D2S2358位点连锁,最大LOD值分别为1．20（0=0）和0．22（0=0）,位于此区域内的CRYGD基因测序后发现一个已经报道的错义突变c．C70A（p．P23T）。结论CRYGD基因P23T突变是该家系结晶样晶状体混浊的致病原因。     

Congenital progressive polymorphic cataract caused by a mutation in the major intrinsic protein of the lens, MIP (AQP0)

BACKGROUND: Congenital cataract, when inherited as an isolated abnormality, is phenotypically and genetically heterogeneous. Although there is no agreed nomenclature for the patterns of cataract observed, a recent study identified eight readily identifiable phenotypes. METHODS: The Moorfields Eye Hospital genetic eye clinic database was used to identify a four generation family with isolated autosomal dominant congenital cataracts. All individuals (affected and unaffected) underwent a full ophthalmic assessment. RESULTS: The results of the molecular linkage study identifying a missense mutation in the gene encoding the major intrinsic protein of the lens (MIP) have been published elsewhere. Affected individuals had bilateral discrete progressive punctate lens opacities limited to mid and peripheral lamellae with additional asymmetric polar opacification. One young female had predominantly cortical cataract and another had serpiginous nuclear opacities. CONCLUSIONS: This phenotype has not been recorded in human families before and has been termed polymorphic. The pattern of opacification appears to reflect the distribution of MIP in the lens. Furthermore, this is the first clear evidence of allelic heterogeneity in this condition following the identification of a family with lamellar cataracts who have a different mutation within the MIP gene.     

Central choroidal thickness in children and adolescents with anxiety disorders: enhanced depth imaging optical coherence tomography findings

AIM: To measure the central choroidal thickness (ChT) in children and adolescents with anxiety disorders. METHODS: Totally 41 anxiety patients (8-16y) and 35 healthy controls (age-matched) were evaluated. Complete ophthalmic examination was performed. Inclusion criteria were best corrected visual acuity ≥20/20, normal intraocular pressure (IOP; 10-21 mm Hg), and no systemic or ocular diseases according to history. The diagnosis of psychiatric disorders was determined using Schedule for Affective Disorders and Schizophrenia for School Aged Children Present-Lifetime Version (K-SADS-PL). Enhanced depth imaging optical coherence tomography (EDI-OCT) was used to measure the central ChT. RESULTS: The mean age was 12.18±3.24y in the patient group and 12.86±3.15y in the control group. Age and gender distribution of the two groups was similar. Central ChT mean value was 353.26±31.9 μm in anxiety patients while 318.75±60.9 μm in the control group. Mean central ChT was statistically significantly higher in the children and adolescents with anxiety disorders than healthy controls (P=0.002). CONCLUSION: The children and adolescents with anxiety disorders have significantly thicker central ChT than controls. In the larger sample, longitudinal studies will contribute to the use of choroidal differences as a clinical marker for monitoring anxiety disorders.     

Investigation of crystallin genes in familial cataract, and report of two disease associated mutations

AIMS: Mutations of seven crystallin genes have been shown to cause familial cataract. The authors aimed to identify disease causing crystallin mutations in paediatric cataract families from south eastern Australia. METHODS: 38 families with autosomal dominant or recessive paediatric cataract were examined. Three large families were studied by linkage analysis. Candidate genes at regions providing significant LOD scores were sequenced. Single stranded conformational polymorphism (SSCP) analysis was used to screen five crystallin genes in the probands, followed by direct sequencing of observed electrophoretic shifts. Mutations predicted to affect the coding sequence were subsequently investigated in the entire pedigree. RESULTS: A LOD score of 3.72 was obtained at the gamma-crystallin locus in one pedigree. Sequencing revealed a P23T mutation of CRYGD, found to segregate with disease. A splice site mutation at the first base of intron 3 of the CRYBA1/A3 gene segregating with disease was identified by SSCP in another large family. Five polymorphisms were also detected. CONCLUSIONS: Although mutations in the five crystallin genes comprehensively screened in this study account for 38% of paediatric cataract mutations in the literature, only two causative mutations were detected in 38 pedigrees, suggesting that crystallin mutations are a relatively rare cause of the cataract phenotype in this population.     

我国汉族常染色体显性遗传性白内障一家系的基因突变分析

目的 寻找一个我国汉族常染色体显性遗传性白内障家系的致病基因.方法 病例对照研究.收集家系的资料,用裂隙灯显微镜检查家系成员的晶状体;提取家系中参与研究的26名成员的基因组DNA,进行白内障致病基因(如晶状体蛋白基因和Cx基因等6个基因)外显子区域的突变扫描,用限制性片段长度多态性分析技术(PCR-RFLP)对检测到的突变进行验证,在42例年龄相关性白内障患者和204名正常人中检测是否存在已筛查到的突变.结果 疾病的表型为粉尘状核性白内障;在Cx50基因(GJA8)的编码核苷酸序列第827位发现一个C到T的新突变,导致在Cx氨基酸序列的276位出现一个丝氨酸到苯丙氨酸的改变,氨基酸由极性中性氨基酸变成疏水性的非极性氨基酸.在42例年龄相关性白内障患者和204名正常人中均未检测到这一突变,同时在晶状体蛋白和Cx基因上发现4个单核苷酸多态性位点.结论 在一个我国汉族显性遗传性白内障家系中发现一个GJA8基因的新突变(P.276 S＞F),可能是该遗传性白内障的致病基因突变.     

A novel mutation of LIM2 causes autosomal dominant membranous cataract in a Chinese family

AIM: To determine the prevalence and associations of non-retinopathy ocular conditions among older Australian adults with diabetes. METHODS: Multistage random-cluster sampling was used to select 3098 non-indigenous Australians aged 50y or older (46.4% male) and 1738 indigenous Australians aged 40y or older (41.1% male) from all levels of geographic remoteness in Australia. Participants underwent a standardised questionnaire to ascertain diabetes history, and a clinical examination to identify eye disease. We determined the prevalence of uncorrected refractive error, visually significant cataract, cataract surgery, age-related macular degeneration, glaucoma, ocular hypertension, retinal vein occlusion and epiretinal membrane among those with and without self-reported diabetes. RESULTS: Participants with self-reported diabetes had a higher prevalence of cataract surgery than those without diabetes (28.8% vs 16.9%, OR 1.78, 95%CI: 1.35-2.34 among non-indigenous Australians, and 11.3% vs 5.2%, OR 1.62, 95%CI: 1.22-2.14 among indigenous Australians). Diabetic retinopathy (DR) increased the odds of cataract surgery among self-reported diabetic indigenous and non-indigenous Australians (OR 1.89, P=0.004 and OR 2.33, P<0.001 respectively). Having diabetes for ≥20y and having vision-threatening DR increased the odds of cataract surgery among indigenous Australians with diabetes (OR 3.73, P=0.001 and 7.58, P<0.001, respectively). CONCLUSION: Most non-retinopathy ocular conditions are not associated with self-reported diabetes. However, to account for Australia’s worsening diabetes epidemic, interventions to reduce the impact of diabetes-related blindness should include increased cataract surgery services.     

Clinical and genetic heterogeneity in autosomal dominant cataract

AIMS: To determine the different morphologies of autosomal dominant cataract (ADC), assess the intra- and interfamilial variation in cataract morphology, and undertake a genetic linkage study to identify loci for genes causing ADC and detect the underlying mutation. METHODS: Patients were recruited from the ocular genetic database at Moorfields Eye Hospital. All individuals underwent an eye examination with particular attention to the lens including anterior segment photography where possible. Blood samples were taken for DNA extraction and genetic linkage analysis was carried out using polymorphic microsatellite markers. RESULTS: 292 individuals from 16 large pedigrees with ADC were examined, of whom 161 were found to be affected. The cataract phenotypes could all be described as one of the eight following morphologies-anterior polar, posterior polar, nuclear, lamellar, coralliform, blue dot (cerulean), cortical, and pulverulent. The phenotypes varied in severity but the morphology was consistent within each pedigree, except in those affected by the pulverulent cataract, which showed considerable intrafamilial variation. Positive linkage was obtained in five families; in two families linkage was demonstrated to new loci and in three families linkage was demonstrated to previously described loci. In one of the families the underlying mutation was isolated. Exclusion data were obtained on five families. CONCLUSIONS: Although there is considerable clinical heterogeneity in ADC, the phenotype is usually consistent within families. There is extensive genetic heterogeneity and specific cataract phenotypes appear to be associated with mutations at more than one chromosome locus. In cases where the genetic mutation has been identified the molecular biology and clinical phenotype are closely associated.