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）知情同意进人本研究,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、GJA8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Βb1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＆gt;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＆gt;A引起。     

先天性白内障一家系晶状体蛋白突变基因筛查

目的对先天性白内障一家系进行晶状体蛋白致病基因的初步筛查。方法通过聚合酶链反应（PCR）对先天性白内障一家系中4代8例患者进行CRYAA、CRYAB、CRYA1／A3、CRYBB2、CRYGC和CRYGD6个候选基因的外显子及内含子扩增,扩增产物进行直接测序,测序结果与GeneBank中原始序列进行BLAST比对分析。结果该家系每代均有先天性白内障患者,遗传方式为常染色体显性遗传。该家系的CRYAA、CRYAB、CRYA1／A3、CRYBB2、CRYGC和CRYGD6个晶状体蛋白候选基因的外显子及其邻近的内含子与基因库对照未发现任何突变。结论CRYAA、CRYAB、CRYA1／A3、CRYBB2、CRYGC和CRYGD为该先天性白内障家系的非致病基因。     

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。     

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.     

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.     

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。     

全外显子组测序法对一中国常染色体显性遗传先天性白内障家系GJA3基因突变位点的分析

背景 先天性白内障是儿童致盲的重要原因,多数先天性白内障与遗传有关.目前已知的与常染色体显性遗传先天性白内障(ADCC)有关的基因有39个. 目的 采用全外显子组测序法对一ADCC家系的致病突变基因进行筛查和分析.方法 纳入2014年8月-9月在郑州大学第一附属医院就诊的一ADCC家系,分别采集家系中14例患者和14名表型正常成员外周静脉血各10 ml,同期同法采集100名健康体检者10 ml的外周静脉血作为对照.用标准酚-氯仿提取法提取所有受检者基因组DNA,并采用全外显子组测序法将先证者的DNA进行全外显子组测序,与数据库对比后筛选出候选基因突变位点,设计突变基因位点引物后采用PCR技术对家系中受检者及100名健康对照者的该基因位点进行扩增并测序,以验证候选基因的致病性并分析其致病机制.结果 该家系共5代68名成员,患病者20例,遗传方式符合常染色体显性遗传方式.患者均双眼发病,晶状体混浊以皮质性为主.先证者全外显子组测序后分析发现,13号染色体GJA3基因的2号外显子第143位核糖核苷酸A突变为G(c.143A＞G),导致其编码的第48位氨基酸由谷氨酸变为甘氨酸(p.E48G).PCR扩增产物测序结果显示该家系中患病受检者DNA均有此突变,但该家系中表型正常的受检者及100名健康对照者该候选基因均不存在此突变.结论 GJA3基因c.143A＞G为该ADCC家系的致病基因突变位点,增补了GJA3基因的突变谱.     

国人常染色体显性先天性白内障家系致病基因的突变分析

目的 分析国人6个常染色体显性先天性白内障(ADCC)家系的基因突变,确定其致病基因及突变形式.设计实验性研究.研究对象6个ADCC家系.方法 应用聚合酶链反应(PCR)和DNA直接测序方法,对家系进行ADCC常见致病基因突变分析.主要指标基因序列.结果 对12个ADCC常见致病基因(CRYAA, CRYAB, CRYBB1, CRYBB2, CRYBA1, CRYGS ,CRYGC, CRYGD, GJA8, GJA3, MIP, BESP2)外显子及外显子内含子连接区进行DNA直接测序,发现7种碱基序列改变,并导致相应编码氨基酸变化,分别是位于CRYBB2基因cDNA序列445位C→T(R145W),452位A→G(0147R),461位C→T(T150M)和388位G→T碱基改变(D126Y);GJA8基因cDNA序列1055位A→G碱基替代(E352G);BFSP2基因cDNA序列1295位C→A(A407D)及MIP基因cDNA序列96位T→A碱基改变(Y23N).其中前3种序列改变已报道为单核苷酸多态性(SNP),经过对相应家系其他成员的分析发现后4种序列改变也为SNP.结论 先天性白内障的临床表型与基因型均有明显的遗传异质性,本试验在12个基因外显子及外显子内含子连接区内未发现导致这6个ADCC家系疾病表型的致病基因突变,但是发现了7种SNP改变,其中4种为本研究首次发现.     

第二代测序技术在一中国先天性白内障家系致病基因检测中的应用

背景 某些遗传性疾病具有高度遗传异质性,因此传统的Sanger测序技术已经不能满足医学研究及临床工作的需求.第二代测序(NGS)技术由于具有费用低及检测速度快的优点而得到广泛应用,但在先天性眼病突变基因的检测中的应用效果有待验证.目的 探讨NGS技术对先天性白内障患者进行致病基因诊断和产前诊断的可行性.方法 于2013年1月收集来自河南省洛阳市的一汉族先天性白内障家系,抽取家系中3例患者(Ⅱ2、Ⅲ3、Ⅲ4)和3名表型正常者(Ⅱ3、Ⅲ1、Ⅲ2)的外周血各2 ml,EDTA抗凝,在河南省医学遗传研究所应用NGS技术对先证者进行基因突变位点检测,并采用Sanger测序技术对NGS结果进行验证,然后用Sanger测序技术对该家系其他成员的外周血样本进行突变位点的序列分析,根据确定的致病突变位点对先证者的胎儿进行产前诊断.本研究遵循赫尔辛基宣言,检测方案经河南省人民医院医学伦理委员会批准,所有研究对象均签署知情同意书.结果 该家系4代14位成员中共5例患者,其中男2例,女3例,分布于Ⅰ、Ⅱ、Ⅲ代中,其他家系成员表型正常,符合常染色体显性遗传方式.NGS检测发现先证者Ⅲ3CRYBB1基因第6外显子上存在c.682T＞C(p.S228P)杂合突变,Sanger法验证了该点突变.Sanger法检测发现家系中患者均存在CRYBB1基因c.682 T＞C突变,而家系中表型正常者CRYBB1基因的c.682位点基因型为T/T野生型.产前诊断结果显示胎儿(Ⅳ1)CRYBB1基因c.682位点基因型为T/T野生型.结论 NGS可用于先天性白内障基因突变的快速检测,该家系致病性基因为CRYBB1基因c.682T＞C突变,应用NGS技术结合一代测序技术成功对先证者进行了产前诊断.     

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。     

Changes in Bruch's membrane in experimental hypercholesteremia in rats

PURPOSE: We investigated the effect of high cholesterol diet for the aging changes in Bruch's membrane of rats. METHODS: After feeding a 4% cholesterol diet for 15 weeks to three young rats 3 months old and four aged rats 23 months old, we observed the morphological changes of Bruch's membrane by electron microscopy, and made a comparison with rats fed an ordinary diet. RESULTS: In one young rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris formed multiple folds separated from the plasma membrane of the endothelium and showed lamellar thickening and crack in some areas. The elastic fiber layer in Bruch's membrane disappeared partly and some new microfibrils appeared. In one aged rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris showed more lamellar thickening with lumps in some parts. Compared with rats fed an ordinary diet, rats fed a high-cholesterol diet showed thickening of the basement membrane and the changes were more severe. CONCLUSIONS: Our data indicated that high-cholesterol diet might promote age-related changes of Bruch's membrane.     

Advances in imaging in oculoplastics

Color Doppler imaging, computed tomography (CT) and magnetic resonance (MR) imaging are the most precious imaging tools for the clinician in the field of oculoplastics. Orbital and facial vasculature, with its dynamic changes and flow velocities seen in orbital varices, carotid-cavernous fistulas, and dural cavernous arteriovenous malformations, is best detected by Color Doppler imaging. Computed tomography remains the dominant imaging modality in the evaluation of orbital trauma. Helical CT axial scanning with multiplanar reconstruction and three-dimensional CT imaging are most helpful in assessing iatrogenic, traumatogenic, and teratogenic orbital abnormalities. Despite its poor histologic specificity, MR imaging provides superior soft tissue contrast, and contrast-enhanced MR imaging has an established role regarding soft tissue tumor infiltration. The greatest value of MR studies in the evaluation of orbital and palpebral tumors is that it has the capacity to show the precise relation between lesions and adjacent structures before the clinician contemplates a surgical approach. Finally, contrast-enhanced MR imaging proved to be a valuable vascularization indicator based upon the extent of relative enhancement within porous orbital implant in anophthalmic socket.     

Follow-up studies in pattern VECP in demyelinating diseases in children

Spectral sensitivity functions and the transient decrease of sensitivity to short wavelengths after the offset of yellow light (transient tritanopia) were measured by increment threshold techniques in patients suffering from hereditary macular degenerations. Color vision defects were determined by arrangement tests and the anomaloscope. Central areolar choroidal dystrophy was found to produce a mild protan defect and to reduce foveal spectral sensitivity throughout the visible spectrum by a factor of 100; it also abolishes transient tritanopia. Electroretinogram (ERG) was normal, electrooculogram (EOG) subnormal. Stargardt's disease, despite numerous fluorescent macular spots, does not abolish transient tritanopia nor does it reduce spectral sensitivity, although scotopic matches were performed on the Nagel anomaloscope. Only in severe, advanced cases was transient tritanopia reduced and spectral sensitivity found to follow the absorption spectrum of rods. Routine ERGs and EOGs were normal. Vitelliform macular degeneration, despite the ophthalmoscopically pronounced dystrophic macula, produced only very small changes in spectral sensitivity and transient tritanopia, although a widened matching range on the Nagel anomaloscope and electrophysiological abnormalities were found. Apparently damage of the retinal circuit which connects long and short wavelength-sensitive cones, caused by hereditary conditions, is different from that caused by retinotoxic drugs.     

Refractive error in children in a rural population in India

PURPOSE: To assess the prevalence of refractive error and related visual impairment in school-aged children in the rural population of the Mahabubnagar district in the southern Indian state of Andhra Pradesh. METHODS: Random selection of village-based clusters was used to identify a sample of children 7 to 15 years of age. From April 2000 through February 2001, children in the 25 selected clusters were enumerated in a door-to-door survey and examined at a rural eye center in the district. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in seven clusters. RESULTS: A total of 4414 children from 4876 households was enumerated, and 4074 (92.3%) were examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 2.7%, 2.6%, and 0.78%, respectively. Refractive error was the cause in 61% of eyes with vision impairment, amblyopia in 12%, other causes in 15%, and unexplained causes in the remaining 13%. A gradual shift toward less-positive values of refractive error occurred with increasing age in both boys and girls. Myopia in one or both eyes was present in 4.1% of the children. Myopia risk was associated with female gender and having a father with a higher level of schooling. Higher risk of myopia in children of older age was of borderline statistical significance (P = 0.069). Hyperopia in at least one eye was present in 0.8% of children, with no significant predictors. CONCLUSIONS: Refractive error was the main cause of visual impairment in children aged between 7 and 15 years in rural India. There was a benefit of spectacles in 70% of those who had visual acuity of 20/40 or worse in the better eye at baseline examination. Because visual impairment can have a significant impact on a child's life in terms of education and development, it is important that effective strategies be developed to eliminate this easily treated cause of visual impairment.     

Vitrectomy in traumatic cataracts and in the complications of surgery in congenital cataract in children

Vitrectomies were carried out in 35 children with traumatic cataracts and complications of surgery for cataracts, caused by injury to the posterior lenticular capsule and incorporation of its fragments to the vitreous. Complete removal of lenticular rudiments rapidly eliminated phacogenic iridocyclitis and improved visual acuity. Improvement of visual functions was attained in 66.6% cases; in 33.4% cases visual acuity did not change. Hemorrhages to the vitreous cavity occurred in 4 cases with pronounced iridocyclitis; therefore, a corneal approach is preferable for cases with pronounced iridocyclitis.