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。     

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。     

东北地区一遗传性白内障家系的临床遗传学及基因定位研究

目的:分析一先天性核型白内障家系的遗传方式及致病基因所在位置。方法:收集一个3代遗传性白内障家系成员的临床资料;提取家系成员外周血DNA,选取62个态性微卫星标记进行连锁分析。应用LINKAGE软件(version 5.2)中的MLINK程序计算两点连锁LOD值,并人工构建家系成员的单体型。结果:确定该家系为一常染色体显性遗传性白内障大家系,在微卫星标记D22S689可获得最大LOD值2.71(θ=0时),单体型提示该家系表型可能与染色体22q11.2-12.1区域连锁。该区域含有CRYBB1,CRYBB2,CRYBB3,CRYBA44个候选基因。结论:本研究先天性核型白内障家系符合常染色体显性遗传规律,其致病基因定位于22q11.2-12.1区域。     

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.     

一个常染色体显性遗传先天性白内障家系致病基因筛查

目的: 对中国一个常染色体显性遗传先天性白内障家系(ADCC)的已知候选基因进行筛查以寻找致病位点。方法: 收集一个ADCC家系的临床资料并采集静脉血。在24个已知与ADCC相关基因附近选择微卫星标记,利用Linkage软件Mlink软件包进行连锁分析计算Lod值。结果: 此家系白内障类型为核性白内障,24个候选基因附近50个微卫星Lod值均小于0,微卫星所在区域与此家系致病基因无连锁关系。结论: 此ADCC家系致病基因不是已知的与ADCC相关基因,可能是一个新的致病基因突变导致此家系疾病发生。     

先天性核性白内障家系致病基因的定位与候选基因突变检测

目的 对中国一常染色体显性遗传性先天性核性白内障家系进行致病基因的定位与候选基因突变检测.方法 实验研究.采集家系成员的外周静脉血,提取基因组DNA.用约400个中密度微卫星标记进行基因扫描,平均遗传距离10厘摩(cM).利用LINKAGE软件包进行连锁分析.在阳性定位区域内选取更为精细的微卫星标记进行精细定位.利用CYRILLIC软件进行单体型分析,确定候选基因所在染色体区域.候选基因直接测序检测基因突变.结果两点间连锁分析在微卫星标记D2S325处获得最大对数优势计分(LOD)值Zmax=2.29(θmax=0.00).精细定位和单体型分析将致病基因定位于微卫星标记D2S117和D2S2382之间,遗传距离约19.04 cM,染色体位置为2q32.3-q35.候选基因直接测序发现CRYGC基因第3外显子第470碱基一个G→A的点突变.结论本研究将我国一个先天性核性白内障家系的致病基因定位于2号染色体2q32.3-q35约19.04cM区域内,并在CRYGC基因发现一个新的点突变与此家系共分离.(中华眼科杂志,2009,45:234-238)     

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。     

遗传性核性金黄色结晶样白内障患者γ晶状体蛋白基因错义突变

目的确定中国北方常染色体显性遗传性白内障（ADCC）-家系的致病基因。方法收集ADCC-家系资料,提取血液白细胞DNA,运用微卫星位点多态性连锁分析,对提示连锁的染色体区域内的候选基因测序,寻找突变。结果该家系致病基因定位在2q33．3-34区域内,对其候选基因γ晶体蛋白基因簇各基因进行测序,发现γD晶体蛋白基因第二外显子有一个杂合子的错义突变（109C→A）与家系患者共分离,此突变可导致其编码的第36位精氨酸被丝氨酸取代。结论此γ晶体蛋白基因突变引起该家系核性结晶样先天性白内障,是由1D晶体蛋白基因109C→A（R36S）突变引起的。（中华腰群杂志,2006,42：913—917）     

常染色体显性视网膜色素变性家系基因定位的研究与视紫红质基因突变的检测分析

对一常染色体显性视网膜色素变性 (autosomaldominantretinitispigmentosa ,ADRP)大家系进行基因定位 ,并检测该家系12名患者的视紫红质基因是否存在突变。方法 :采用多个已知位点的遗传标记对该ADRP家系进行连锁分析 ,确定致病基因的大致染色体位置 ;在所定位的染色体区域将RHO基因作为侯选基因进行直接测序检测突变。结果 :连锁分析结果发现遗传标记D3S12 92 ,当θ =0 1时有最大Lod值 =2 732 85 2 ,因此考虑该家系致病基因位于D3S12 92附近。直接测序结果发现该家系中大部分患者在RHO基因的第 3外显子序列 ,第 182密码子的第 2个碱基发生G→A置换突变 ,导致甘氨酸 (Gly)变为天冬氨酸 (Asp) ,命名为Gly -182 -Asp突变 ,而在 2例患者中则未发现突变 ;同时 ,在该家系正常成员以及正常对照者中均未发现此突变。结论 :ADRP存在分子水平的遗传异质性 ,某些ADRP是由于RHO基因突变所致。但是由于本研究所涉及的ADRP家系中尚有2名患者未找到RHO基因突变 ,故不能将Gly -182 -Asp突变认为是该家系的致病原因。在D3S12 92与RHO基因之间可能存在新的基因 ,还需进一步研究证明。     

先天性膜性白内障一家系致病基因的遗传分析

目的 分析一个先天性白内障家系的遗传规律,对其突变基因进行初步研究.方法 选取一先天性膜性白内障家系,对家系成员进行临床检查并采集静脉血.标准饱和酚/氯仿抽提法提取DNA,选取多态性微卫星遗传标记,合成引物,聚合酶链反应,聚丙烯酰胺凝胶电泳,基因分型,等位基因共享分析法对已知候选基因进行排除性定位.结果 该家系为常染色体显性遗传性先天性白内障家系.其致病基因与D22S315联系紧密,重组发生在以D22S303和D22S1167为上下边界的范围内.对该范围内已知的先天性白内障致病基因CRYBB1、CRYBB2、CRYBB3、CRYBA4进行DNA直接测序,未发现突变.结论 该家系致病基因定位于22q11.2～q12.1的2.4 Mbp范围内,其致病基因与已知基因座不同.该范围内可能存在导致先天性膜性白内障的新的致病基因.     

土家族中一个先天性无虹膜家系的临床特点和PAX6基因突变位点分析

目的：确认土家族中一个先天性无虹膜家系的PAX6基因致病突变并分析其临床特点。方法：实验研究。详细询问家族病史并对该家系中所有7 例成员（4 例患者,3 例正常人）进行详细的眼部检查,采集家系成员及100例（50例土家族人和50例汉族人）正常对照者的外周静脉血,提取DNA;对先证者PAX6基因的全部外显子进行PCR扩增及测序;对家系中所有成员和正常对照者进行PAX6基因突变位点的验证检测。结果：该家系中患者主要以虹膜缺损、白内障、眼球震颤、黄斑中心凹发育不良和角膜病变为主要临床表现,虹膜缺损轻重不一,角膜病变和白内障情况随年龄增加而加重。该家系的4 例患者均在第3 外显子与内含子3 交界处出现一个杂合突变（c.357+1G > A）,正常家系成员及正常对照者均无此突变。结论：该先天性无虹膜家系患者虹膜缺损程度不一。PAX6是该家系的致病基因,该家系患者PAX6基因的突变位点是杂合突变(c.357+1G > A）。     

A common disease haplotype for the Q368STOP mutation of the myocilin gene in Australian and Canadian glaucoma families

PURPOSE: To ascertain whether there is a common disease haplotype for the Q368STOP mutation of the myocilin gene in Australian and Canadian families with primary open-angle glaucoma (POAG). DESIGN: Family pedigree study. METHODS: A disease haplotype for the Q368STOP mutation of the myocilin gene has previously been identified in 15 Tasmanian families with POAG. The four microsatellite markers that constitute this 0.14-megabase (Mb) disease haplotype were genotyped in individuals from a large French Canadian family with POAG (family CT) and two unrelated French Canadian individuals with ocular hypertension. RESULTS: The Tasmanian Q368STOP disease haplotype was identified in affected individuals from family CT, and the same alleles were shared at the four microsatellite markers in the two unrelated French Canadian individuals. CONCLUSION: The same disease haplotype for the Q368STOP mutation of the myocilin gene was found in both the Tasmanian and French Canadian populations, supporting the view that this mutation arose from a common Caucasian founder.     

重庆忠县原发性开角型青光眼家系的临床表型和遗传学分析

目的:对重庆POAG家系进行调查,分析遗传特点和临床表型。方法:追踪家系成员,收集病史资料,进行眼科常规检查。总结家系POAG患者发病的临床特点,根据孟德尔法则对本家系遗传方式进行分析。结果:该家系可追踪到的有5代共54例,男29例,女25例。已确诊的POAG患者17例,男11例,女6例,6例死亡。确诊年龄28~64(平均38.6)岁。发病眼眼压25~39mmHg,平均31.63±5.14mmHg。治疗后视野视力仍进行性恶化的7例。结论:该家系患者符合青年性POAG,常规治疗效果差,应存在除机械压迫以外的其他致病因素。家系中POAG发病者为突变等位基因常染色体显性遗传的结果,在本家系中存在导致POAG发病的突变的等位基因。     

Sorsby fundus dystrophy without a mutation in the TIMP-3 gene

AIMS: To examine a large family with an autosomal dominant fundus dystrophy and to investigate whether or not mutations in TIMP-3 gene were involved. METHODS: A large family of 58 individuals with an autosomal dominant fundus dystrophy was examined ophthalmologically. A DNA linkage analysis in the 22q12.1-q13.2 region was performed. The TIMP-3 gene was screened for mutations in all five exons. RESULTS: In this large family 15 individuals were affected. All other individuals were found to be clinically unaffected. Pisciform flecks in the midperiphery and drusen-like deposits were the most typical ophthalmological finding in this family and were encountered from the fifth decade on. Chorioretinal atrophy and neovascularisation with disciform lesions characterised the disease from the sixth decade on. Linkage analysis using an affected only analysis, showed a maximum positive lod score of 3.94 at theta = 0.0 with marker D22S283. No mutations possibly causing Sorsby fundus dystrophy were found in either the exonic sequences, the promotor region, or the 3'UTR. CONCLUSION: The family in this pedigree has an autosomal dominant fundus dystrophy, which is most probably Sorsby fundus dystrophy. Although, in the linkage analysis, significant positive lod scores were found with the region 22q12.1-q13.2, no causative mutations could be identified in the TIMP-3 gene.     

A practice-based survey of familial age-related maculopathy

PURPOSE : We evaluated the efficacy of a practice-based survey of age-related maculopathy (ARM) to identify potential families for molecular genetic studies. Demographic and ophthalmic features of the eligible study population were compared with responders and with individuals who reported a positive family history of ARM. METHODS : Individuals seen within a three-year period in a comprehensive ophthalmic practice were identified through billing codes. Clinical records were reviewed, coded, and merged with questionnaire responses. Patient identifiers were removed prior to analyses. RESULTS : There were no significant differences between the respondents and the eligible cohort with respect to gender, age, or type of macular degeneration. Comparable percentages of younger and older individuals with ARM reported positive family histories. The distribution of atrophic macular degeneration, choroidal neovascular membranes, and milder forms of the disease among the individuals reporting positive family histories corresponded to the distribution of the entire eligible cohort of patients. CONCLUSIONS : This recruitment strategy for ARM families is cost-effective and confirmed a high prevalence of familial ARM. The respondents are representative of the general ARM population. This approach is applicable for other ophthalmic genetic conditions.     

Autosomal dominant peripheral cystic retinal patches and non-cystic retinal tufts associated with peripapillary crescents, retinal breaks and uveitis

PURPOSE: To characterise an Irish kindred with apparent autosomal dominant peripheral retinal lesions and peripapillary crescents associated with retinal breaks and uveitis and assess whether these findings were associated with altered homocysteine metabolism. METHODS: Family members were followed prospectively and regularly examined. Molecular genetic analysis was performed on family members to detect cystathionine beta-synthase (CBS) 307G-S and 5,10-methylenetetrahydrofolate (MTHFR) 677C-T mutations. RESULTS: Over 11 years, 25 family members in four generations were examined, none of whom had significant refractive errors. Fifteen affected individuals had peripheral cystic retinal patches and in some cases non-cystic retinal tufts, associated with peripapillary pigmentation. Mean age at first examination of affected and non-affected individuals was the same. During follow-up the fundal findings remained unchanged in the affected group and no clinical characteristics developed in the unaffected individuals. Two affected siblings had associated uveitis and rhegmatogenous retinal detachment, which were successfully treated, while a third affected individual had a pigmented retinal break not requiring treatment. Heterozygosity for the CBS 307G-S mutation did not segregate with affected individuals while the MTHFR 677C-T mutation was not detected. CONCLUSIONS: This family has previously undescribed fundal findings inherited in an apparent autosomal dominant pattern associated with retinal breaks and uveitis. There is no associated inherited alteration of homocysteine metabolism.     

Polymorphic corneal amyloidosis: a disorder due to a novel mutation in the transforming growth factor beta-induced (BIGH3) gene

PURPOSE: To characterize the clinicopathologic phenotype as well as the molecular genetic basis of an autosomal dominant form of corneal amyloidosis. DESIGN: Clinicopathologic and molecular genetic study of a family with a form of corneal amyloidosis. PARTICIPANTS: Forty-nine individuals from one family were studied. METHODS: The medical records of affected family members were reviewed, and corneal tissue from those who had undergone penetrating keratoplasty (PK) was examined. Several family members were examined clinically, and corneas were photographed. Deoxyribonucleic acid from blood or buccal swabs was extracted from each consenting family member to determine the status of their transforming growth factor beta-induced (TGFBI) gene. The coding region of the TGFBI gene was analyzed for mutations in the proband's DNA, and compared with the nucleotide sequences of normal individuals. This was performed by amplifying and sequencing all exons of the TGFBI gene. In all other family members, only exons 4, 8, 11, and 12 of the gene were amplified, sequenced, and analyzed for mutations. MAIN OUTCOME MEASURES: Clinicopathologic manifestations in relation to mutational status of the TGFBI gene. RESULTS: Slit-lamp biomicroscopy revealed bilateral multiple polymorphic, polygonal, refractile, chipped ice-appearing gray and white opacities. There were also occasional deep filamentous lines that did not form a distinct lattice pattern. Corneal tissue of affected individuals who underwent PK contained widespread deposits of amyloid within the corneal stroma, particularly in the deep central stroma. Twelve members of the family were found to have a heterozygous single mutation in the TGFBI gene leading to a predicted amino acid substitution of aspartic acid for alanine (A546D). Nine of these individuals had ophthalmologist-documented corneal disease. The remaining 3, who were 11, 14, and 15 years old, were asymptomatic. In addition, 4 inconsequential polymorphisms with the nucleotide changes 387 G/A (R129R), 981 G/A (V327V), 1416 T/C (L472L), and 1620 C/T (F540F) were found. CONCLUSION: A distinct, progressive form of corneal amyloidosis with an autosomal dominant mode of inheritance is characterized clinically by the presence of refractile polymorphic corneal opacities. We have designated this entity, which is caused by an A546D mutation in the TGFBI gene, polymorphic corneal amyloidosis.     

Phenotype and genotype correlations in two best families

OBJECTIVE: To evaluate mutations in the Best mascular dystrophy (VMD2) gene in two families with Best disease and to describe the phenotype-genotype correlations of genetically determined affected and unaffected individuals. DESIGN: Family genetic study. PARTICIPANTS: Two families with Best disease were identified, and family members were evaluated by ophthalmologic examination or fundus photography to assess their phenotype. All affected patients and some of the unaffected family members had a blood sample drawn, and the DNA was analyzed for mutations in the VMD2 gene. MAIN OUTCOME MEASURES: Twenty-one subjects in the two pedigrees with Best disease were studied. One amino acid-changing mutation in the VMD2 gene was found to segregate independently in each family (P297S or E300D, respectively). RESULTS: Eleven individuals had some evidence of maculopathy, including retinal pigment epithelial changes, drusen, pigment epithelial irregularities, or cicatricial changes. Ten of these 11 patients (91%) with maculopathy had a mutation in the VMD2 gene, of whom 8 were clinically diagnosed as having Best disease and 2 were diagnosed as having possible Best maculopathy. The one patient without a mutation in the VMD2 gene had age-related macular degeneration (AMD). Ten family members did not have evidence of maculopathy, of whom 6 had no mutation in the VMD2 gene. Four family members (2 in each pedigree) had mutations in the VMD2 gene, abnormal electro-oculogram (EOG) results, but normal maculae at age 40 or older. Of the 7 individuals with no mutation in the VMD2 gene, 6 were phenotypically normal and the other had late-onset visual loss resulting from AMD. CONCLUSIONS: All family members with maculopathy consistent with Best disease (n = 10) had an amino acid-changing mutation in the VMD2 gene. Four individuals who did not have maculopathy, but did have an abnormal EOG, also had mutations in the VMD2 gene. The presence of a VMD2 mutation is associated with abnormal retinal function, which can occur in the absence of phenotypic manifestation of macular disease.     

Congenital stationary night blindness and a "Schubert-Bornschein" type electrophysiology in a family with dominant inheritance

BACKGROUND/AIMS: To present the clinical, psychophysical, and electrophysiological characteristics of a family with dominantly inherited congenital stationary night blindness (CSNB). METHODS: Five affected family members from three generations were ascertained. Four affected individuals underwent ophthalmic examination and electrodiagnostic investigations. Three affected individuals also underwent scanning laser ophthalmoscopy and psychophysical testing. RESULTS: Affected individuals reported night blindness from an early age. Visual acuities were normal. Fundal appearances were normal apart from one older patient showing areas of peripheral chorioretinal atrophy. Autofluorescence images showed no gross abnormality. International Society for Clinical Electrophysiology of Vision (ISCEV) standard electroretinography (ERG) showed undetectable rod specific responses and electronegative maximal responses, but normal ISCEV cone responses. Additional S-cone specific ERG recordings were of reduced amplitude in all patients studied. There was no apparent rod component to the dark adaptation curve. Central 30 degrees thresholds were normal under photopic conditions but showed increased thresholds under scotopic conditions for both red and blue stimuli. CONCLUSION: Results from investigation of this family are consistent with an impairment of rod photoreceptor signalling. The ERG findings suggest an abnormality occurring after phototransduction with rod and S-cone pathway involvement. These findings differ from those rare families reported previously with dominant CSNB.     

Variant phenotype of Best vitelliform macular dystrophy associated with compound heterozygous mutations in VMD2

PURPOSE: To characterize the phenotype of members of a Swedish family with Best macular dystrophy and two distinct mutations in VMD2. METHODS: Venous blood samples were obtained from six family members and screened for mutations in VMD2. Six individuals were examined clinically, four of whom were further investigated with full-field electroretinography (ERG), electro-oculography (EOG), multifocal electroretinography (mfERG), and optical coherence tomography (OCT). RESULTS: The VMD2 mutations resulting in Arg141His and Tyr29stop were identified in family members. Two individuals harbored both mutations, one mutation in each VMD2 allele. These two family members had an abnormal EOG and their full-field ERG demonstrated widespread degeneration with a prolonged implicit time in the cone 30-Hz flicker ERG. MfERG verified reduction of the central retinal function and OCT demonstrated intraretinal fluid, swelling, and thickening of the outer retina-RPE-choroid complex (ORCC). CONCLUSION: A previously undescribed severe form of Best macular dystrophy is associated with compound heterozygous mutations in VMD2.