常染色体显性遗传核性白内障合并小角膜的CRYAA基因突变研究

目的 研究一个4代常染色体显性遗传先天性核性白内障伴小角膜家系的致病基因.方法 实验研究.对12例家系成员(6例患者,6例非患者)进行眼部检查并采集静脉血,提取基因组DNA.在已知的与先天性白内障伴小角膜相关致病基因附近选择微卫星标记,进行聚合酶链反应扩增-变性聚丙烯酰胺凝胶电泳,并进行基因型分析和连锁分析.对连锁区域内候选基因的外显子、外显子和内含子交界区进行测序.限制性内切酶ApaL Ⅰ法在全部家系成员和正常人群中验证突变.结果 该家系患者表型为先天性核性白内障伴小角膜;在染色体21q22.3区域的D21S1885和D21S1890两个标记,家系患者均有共享基因型,并且两点连锁分析Lod值为2.11,提示该位点与家系致病基因连锁;对此区域内候选基因CRYAA测序发现cDNA序列第34位碱基存在C＞T杂合突变(c.34C＞T),导致其编码肽链第12位精氨酸变为半胱氨酸(p.R12C).ApaL Ⅰ酶切验证家系患者均携带c.34C＞T突变,家系中及对照正常个体均不携带此突变.结论 CRYAA的p.R12C突变可能是该先天性白内障伴小角膜家系发病的遗传基础.

Abstract：

Objective To identify the gene mutation in a four-generation Chinese family with autosomal dominant congenital cataract associated with microcornea. Methods Experimental research.Twelve members in this family (including six affected and six unaffected individuals) were enrolled into this study. They underwent full ophthalmological and clinical examinations to rule out any concomitant disorders.Blood samples were collected and genomic DNA was extracted. Microsatellite markers near the reported loci,which are associated with congenital cataract and microcornea were selected and amplified from DNA samples using polymerase chain reaction. Linkage analysis was performed. The exons and exon/intron junction of candidate gene in the related chromosome were sequenced. The product of the first exon was digested by ApaL Ⅰ restriction enzyme to certify the mutation. Results The phenotype studied in this family was nuclear cataract accompanied with microcornea. At markers D21S1885 and D21S1890 near the locus 21q22. 3, the affected members had the same allele, but the unaffected did not. The Lod scores were 2. 11in both markers, indicating that this locus were linked to the congenital cataract in this family. DNA sequencing of candidate gene CRYAA showed a heterozygous mutation c. 34C ＞ T in exon 1, which led to condon 12 in peptide chain encoding arginine substituted by cysteine. ApaL Ⅰ enzyme digestion certified that all of the affected members had the same mutation c. 34C ＞T, but the unaffected and normal individuals did not. Conclusion Mutation (p. R12C) of CRYAA is the genetic change that causes the occurrence of congenital cataract with microcornea in this family.     

常染色体显性遗传核性白内障合并小角膜的CRYAA基因突变研究

Objective To identify the gene mutation in a four-generation Chinese family with autosomal dominant congenital cataract associated with microcornea. Methods Experimental research.Twelve members in this family (including six affected and six unaffected individuals) were enrolled into this study. They underwent full ophthalmological and clinical examinations to rule out any concomitant disorders.Blood samples were collected and genomic DNA was extracted. Microsatellite markers near the reported loci,which are associated with congenital cataract and microcornea were selected and amplified from DNA samples using polymerase chain reaction. Linkage analysis was performed. The exons and exon/intron junction of candidate gene in the related chromosome were sequenced. The product of the first exon was digested by ApaL Ⅰ restriction enzyme to certify the mutation. Results The phenotype studied in this family was nuclear cataract accompanied with microcornea. At markers D21S1885 and D21S1890 near the locus 21q22. 3, the affected members had the same allele, but the unaffected did not. The Lod scores were 2. 11in both markers, indicating that this locus were linked to the congenital cataract in this family. DNA sequencing of candidate gene CRYAA showed a heterozygous mutation c. 34C ＞ T in exon 1, which led to condon 12 in peptide chain encoding arginine substituted by cysteine. ApaL Ⅰ enzyme digestion certified that all of the affected members had the same mutation c. 34C ＞T, but the unaffected and normal individuals did not. Conclusion Mutation (p. R12C) of CRYAA is the genetic change that causes the occurrence of congenital cataract with microcornea in this family.     

常染色体显性遗传核性白内障合并小角膜的CRYAA基因突变研究

Objective To identify the gene mutation in a four-generation Chinese family with autosomal dominant congenital cataract associated with microcornea. Methods Experimental research.Twelve members in this family (including six affected and six unaffected individuals) were enrolled into this study. They underwent full ophthalmological and clinical examinations to rule out any concomitant disorders.Blood samples were collected and genomic DNA was extracted. Microsatellite markers near the reported loci,which are associated with congenital cataract and microcornea were selected and amplified from DNA samples using polymerase chain reaction. Linkage analysis was performed. The exons and exon/intron junction of candidate gene in the related chromosome were sequenced. The product of the first exon was digested by ApaL Ⅰ restriction enzyme to certify the mutation. Results The phenotype studied in this family was nuclear cataract accompanied with microcornea. At markers D21S1885 and D21S1890 near the locus 21q22. 3, the affected members had the same allele, but the unaffected did not. The Lod scores were 2. 11in both markers, indicating that this locus were linked to the congenital cataract in this family. DNA sequencing of candidate gene CRYAA showed a heterozygous mutation c. 34C ＞ T in exon 1, which led to condon 12 in peptide chain encoding arginine substituted by cysteine. ApaL Ⅰ enzyme digestion certified that all of the affected members had the same mutation c. 34C ＞T, but the unaffected and normal individuals did not. Conclusion Mutation (p. R12C) of CRYAA is the genetic change that causes the occurrence of congenital cataract with microcornea in this family.     

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)     

*常染色体显性先天性缝合状白内障家系致病基因的定位

目的对我国一常染色体显性先天性缝合状白内障家系进行致病基因的定位。方法采集家系成员外周静脉血提取基因组DNA。选用美国Applied Biosystems公司提供的约400个遗传标记物进行基因扫描。数据经Linkage软件包进行连锁分析,初步确定致病基因所在染色体区域。在阳性区域内选取更高密度的荧光标记物进行精细扫描,用Cyrillic软件进行单体型分析。结果两点间连锁分析在D3S1279处获得最大对数优势记分（LOD）值Zmax=2．32（θmax=0．00）。通过精细扫描和单体型分析将致病基因定位于D3S1267和D3S1614之间约38．6厘摩（cM）区域内。结论先天性缝合状白内障家系的致病基因位于3号染色体3q21．1-q26．2约38．6cM区域内。（中华腥科杂志,2006,42：908—912）     

A mutated CRYGD associated with congenital coralliform cataracts in two Chinese pedigrees

AIM: To investigate the causal gene mutation and clinical characteristics for two Chinese families with autosomal dominant congenital coralliform cataract. METHODS: Two Chinese pedigrees with congenital cataract were investigated. Routine ophthalmic examinations were performed on all patients and non-affected family members. Peripheral blood samples were collected, and the genomic DNAs were extracted. The coding regions of proband’s DNAs were analyzed with cataract gene panel. The identified mutation was amplified by polymerase chain reaction, and automated sequencing was performed in other members of two families to verify whether the mutated gene was co-segregated with the disease. RESULTS: Congenital coralliform cataract was inherited in an autosomal dominant mode in both pedigrees. For each family, more than half of the family members were affected. All patients presented with severe visual impairment after birth as a result of bilateral symmetric coralliform lens opacification. An exact the same defect in the same gene, a heterozygous mutation of c.70C>A (p. P24T) in exon 2 of γD-crystallin gene, was detected in both probands from each family. Sanger sequencing analysis demonstrated that the mutated CRYGD was co-segregated in these two families. CONCLUSION: A c.70C>A (p. P24T) variant in CRYGD gene was reconfirmed to be the causal gene in two Chinese pedigrees. It is known that mutated CRYGD caused most of the congenital coralliform cataracts, suggesting that the CRYGD gene is associated with coralliform congenital cataract.     

Reliability of Chinese web-based ocular surface disease index questionnaire in dry eye patients: a randomized, crossover study

AIM: To investigate the causal gene mutation and clinical characteristics in two Chinese families with autosomal dominant congenital coralliform cataracts. METHODS: Two unrelated Chinese pedigrees with congenital cataract were investigated. Routine ophthalmic examinations were performed on all patients and non-affected family members. Peripheral blood samples were collected, and the genomic DNAs were extracted. The coding regions of probands’ DNAs were analyzed with cataract gene panel. The identified gene was amplified by polymerase chain reaction and sequenced in other members of two families to verify if the mutated gene was co-segregated with the disease. RESULTS: Congenital coralliform cataract was inherited in an autosomal dominant mode in both pedigrees. For each family, more than half of the family members were affected. All patients presented with severe visual impairment after birth as a result of bilateral symmetric coralliform lens opacification. An exact same defect in the same gene, heterozygous mutation of c.70C>A (p. P24T) in exon 2 of γD-crystallin CRYGD gene, was identified in both probands from each family. Sanger sequencing analysis demonstrated that the mutated CRYGD was co-segregated in these two families. CONCLUSION: A known substitution c.70C>A (p. P24T) in CRYGD gene appears to be the disease-causing gene in these two Chinese families. It is known that mutated CRYGD caused most of the congenital coralliform cataracts, suggesting that the CRYGD gene are associated with phenotype of congenital coralliform cataract.     

花冠状常染色体显性遗传性先天性自内障致病基因初步定位

目的 初步定位具有花冠状表型的常染色体显性遗传性先天性白内障一家系的致病基因.方法 收集家系成员的资料,提取基因组DNA,据文献报道在已知先天性白内障致病基因和位点附近,选择合适的短串联重复序列多态性标记,使用LINKAGE 5.1软件计算标准LOD值,对此家系进行连锁分析.结果 此表型先天性白内障的致病基因定位在3q22.3-q25.2,即D3S3612至D3S1594之间15.2 cM范围内.在D3S1569和D3S3599处,得到与致病基因住点连锁的最大LOD值均为3.01(重组率=0.00).结论 该花冠状常染色体显性遗传性先天性白内障致病基因初步定位在第3对染色体上3q22.3-q25.2.     

Avellino角膜营养不良家系致病基因的定位研究

目的：对收集到的一个常染色体显性遗传性Avellino角膜营养不良家系的致病基因进行初步定位。
　　方法：采集家系中所有成员的外周静脉血,从中提取基因组DNA样本。在热点区域内选取微卫星标记进行基因扫描,分别利用LINKAGE软件和CYRILLIC软件进行连锁分析及单体型分析,以确定候选基因所在的染色体区域。
　　结果：该Avellino角膜营养不良家系的连锁分析结果在D5 S396和D5 S393这两个微卫星标记处获得最大优势对数计分(LOD)值,Zmax=3.01(θ=0.00)。单体型分析将致病基因定位于微卫星标记D5 S808和D5 S638之间。
　　结论：该Avellino角膜营养不良家系的致病基因初步定位于染色体5q上的遗传距离约为11.2厘摩( cM)的一段区域内。     

先天性广泛眼外肌纤维化综合征一家系的连锁分析和候选基因研究

目的探讨先天性广泛眼外肌纤维化综合征(CFEOM)一家系的临床表型特征和致病基因。方法收集CFEOM一家系,对全部患者进行临床检查和全基因组扫描及连锁分析(1inkage analysis),对连锁区域内的候选基因KIf21A进行基因序列分析。结果此家系中4例患者具有典型CFEOM临床表现。连锁分析显示微卫星标记物D12S1648、D12s345、D12S1692、D12S59、D12S1090、D12S2194、D12S1048、D12S1668在家系中与全部患者的疾病表型共分离,并在D12S1090取得最大LOD值(2．12)。KIf21A基因测序未发现突变,仅在外显子21发现一单个碱基多态性改变。结论此家系属常染色体显性遗传CFEOM1型,致病基因定位于染色体带12p11．2-q12微卫星标记物D12S1648和D12S1668之间约4cM的区域。KIF21A基因可能不是此家系的致病基因。(中华眼科杂志,2005,41：594-599)     

Genetic heterogeneity in microcornea-cataract: five novel mutations in CRYAA, CRYGD, and GJA8

PURPOSE: To unravel the molecular genetic background in families with congenital cataract in association with microcornea (CCMC, OMIM 116150). METHODS: CCMC families were recruited from a national database on hereditary eye diseases; DNA was procured from a national gene bank on hereditary eye diseases and by blood sampling from one large family. Genomewide linkage analysis, fine mapping, and direct genomic DNA sequencing of nine cataract candidate genes were applied. Restriction enzyme digests confirmed identified mutations. RESULTS: Analyses of 10 Danish families with hereditary congenital cataract and microcornea revealed five novel mutations. Three of these affected the crystallin, alpha-A gene (CRYAA), including two mutations (R12C and R21W) in the crystallin domain and one mutation (R116H) in the small heat shock domain. One mutation (P189L) affected the gap junction protein alpha 8 (GJA8), and one mutation (Y134X) was detected in crystallin gamma-D (CRYGD). CONCLUSIONS: The identification of a CRYGD mutation adds another gene to those that may be mutated in CCMC and underscores the genetic heterogeneity of this condition. Three CRYAA mutations at the R116 position, in association with CCMC, suggest that R116 represents a CCMC-mutational hotspot. The CCMC phenotype demonstrates variable expression with regard to cataract morphology and age of appearance. Clinical heterogeneity, including additional malformation of the anterior segment of the eye, confirm that dedicated cataract genes may be involved in the largely unknown developmental molecular mechanisms involved in lens-anterior segment interactions.     

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。     

Posterior Polar Cataract: Genetic Analysis of a Large Family

Congenital cataracts are clinically and genetically heterogeneous. Loci for autosomal dominant posterior polar cataracts have been mapped to chromosomes 1p36, 11q22-q22.3, 16q22, and 20p12-q12. We investigated a large four-generation family with 20 individuals affected with congenital posterior polar cataracts. After exclusion of known loci for posterior polar cataracts, a genome-wide screen was conducted. In this family, we mapped dominant congenital posterior polar cataracts to chromosome 10q24. On haplotype analysis, we identified an 11-cM interval between loci D10S1680 and D10S467, which included the PITX3 gene. On sequencing the coding region of PITX3, we found a 17-base-pair duplication in exon 4. Although the same genotype was described in a family with ASMD and cataracts, the common phenotype of this mutation is probably posterior polar cataract; a modifier gene is presumed to cause anterior segment abnormalities in the previously described patients. The same mutation was recently identified in four families with congenital cataracts. This study provides further evidence of genetic heterogeneity of autosomal dominant posterior polar cataract.     

Posterior polar cataract: genetic analysis of a large family

Congenital cataracts are clinically and genetically heterogeneous. Loci for autosomal dominant posterior polar cataracts have been mapped to chromosomes 1p36, 11q22-q22.3, 16q22, and 20p12-q12. We investigated a large four-generation family with 20 individuals affected with congenital posterior polar cataracts. After exclusion of known loci for posterior polar cataracts, a genome-wide screen was conducted. In this family, we mapped dominant congenital posterior polar cataracts to chromosome 10q24. On haplotype analysis, we identified an 11-cM interval between loci D10S1680 and D10S467, which included the PITX3 gene. On sequencing the coding region of PITX3, we found a 17-base-pair duplication in exon 4. Although the same genotype was described in a family with ASMD and cataracts, the common phenotype of this mutation is probably posterior polar cataract; a modifier gene is presumed to cause anterior segment abnormalities in the previously described patients. The same mutation was recently identified in four families with congenital cataracts. This study provides further evidence of genetic heterogeneity of autosomal dominant posterior polar cataract.     

Recessive congenital total cataract with microcornea and heterozygote carrier signs caused by a novel missense CRYAA mutation (R54C)

PURPOSE: To determine the genetic basis for congenital total white cataract with microcornea in three affected siblings. DESIGN: Prospective interventional case series. METHODS: Clinical ophthalmic examination, venous blood sampling for linkage analyses, and diagnostic testing of identified candidate gene(s). RESULTS: Three siblings had congenital total white cataract with microcornea; the parents and seven other siblings were asymptomatic. Linkage analysis mapped the phenotype to Hsa 21q22.3, the region of the gene for the alpha-A component of alpha-crystallin (CRYAA), with a logarithm of odds (LOD) score of 2.5. Diagnostic CRYAA sequencing revealed a novel homozygous nonsense mutation (R54C) in the three affected individuals only. One other sibling and the two parents were heterozygotes; these individuals had punctuate lenticular opacities evident by careful slit-lamp biomicroscopy which were not present in the noncarriers, all of whom had unremarkable ophthalmic examinations. CONCLUSION: R54C is the second reported recessive CRYAA mutation associated with congenital cataract and the first with described morphology: punctuate lenticular opacities in carriers and congenital total white cataract with microcornea in homozygotes. The microcornea may have been caused by an inductive effect on the developing cornea from the abnormal lens and/or reduced CRYAA molecular chaperoning of the cornea.     

先天性粉尘状白内障一家系基因突变定位

目的 探讨先天性粉尘状白内障一家系的基因突变定位.方法 回顾性研究.对一先天性白内障家系成员(共32人,其巾患者15人)散瞳后采用裂隙灯显微镜观察晶状体,并取外周血提取DNA样品.选取常染色体上微卫星标记物,通过聚合酶链反应(PCR)进行扩增后,进行基因扫描.利用GeneMapper软件进行PCR扩增产物片段大小和单体型分析.分别通过Linkage 5.1和GeneHunter软件进行两点法和多点法对数优势记分(LOD)值计算.对候选基因通过测序进行基因序列分析.结果 家系成员中的白内障患者晶状体环胎儿核可见散在的类似于蚁卵的短棒状混浊.在不同患者间以及同一患者的不同眼别存在晶状体混浊程度和形态的差异.两点法计算LOD值,在重组率(θ)为0时,微卫星位点D20S186、D230S163、D20S915、D20S152、D20S98、D20S904、D20S875、D20S112、D20S1140、D20S432均获得正值,其中在D20S904获得最大LOD值6.02.通过单体型构建,发现微卫星位点D20S163在Ⅳ7患者发生交换,而D20S912在Ⅱ3患者发生交换.基因序列分析未发现BFSP1、PLCB4基因突变.结论 该家系突变基因位于常染色体20p12.1-p11.23上微卫星位点D20S186和D20S912间5.47厘摩范围内.