A rare missense PAX6 mutation causes atypical aniridia in a three-generation Chinese family

●AIM:To investigate the molecular diagnosis of a threegeneration Chinese family affected with aniridia,and further to identify clinically a PAX6 missense mutation in members with atypical aniridia.●METHODS:Eleven family members with and without atypical aniridia were recruited.All family members underwent comprehensive ophthalmic examinations.A combination of whole exome sequencing(WES)and direct Sanger sequencing were performed to uncover the causative mutation.●RESULTS:Among the 11 family members,8 were clinically diagnosed with congenital aniridia(atypical aniridia phenotype).A rare heterozygous mutation c.622C>T(p.Arg208Trp)in exon 8 of PAX6 was identified in all affected family members but not in the unaffected members or in healthy control subjects.●CONCLUSION:A rare missense mutation in the PAX6 gene is found in members of a three-generation Chinese family with congenital atypical aniridia.This result contributes to an increase in the phenotypic spectrum caused by PAX6 missense heterozygous variants and provides useful information for the clinical diagnosis of atypical aniridia,which may also contribute to genetic counselling and family planning.

Analysis of Phenotypes Associated with Deficiency of PAX6 Haplotypes in Chinese Aniridia Families

Objective To examine the clinical phenotype and genetic deficiencies present in Chinese aniridia families with PAX6 haplotype deficiency.Methods A comprehensive questionnaire and ophthalmological assessments were administered to both affected patients and unaffected relatives.The clinical feature analysis included the evaluation of visual acuity,intraocular pressure,slit-lamp anterior segment examination,fundus photography,and spectral domain optical coherence tomography.To identify the mutation responsible for aniridia,targeted next-generation sequencing was used as a beneficial technique.Results A total of 4 mutations were identified,consisting of two novel frameshift mutations(c.314delA,p.K105Sfs*33 and c.838_845dup AACACACC,p.S283Tfs*85),along with two recurring nonsense mutations(c.307C>T,p.R103X and c.619A>T,p.K207*).Complete iris absence,macular foveal hypoplasia,and nystagmus were consistent in these PAX6 haplotype-deficient Chinese aniridia families,while corneal lesions,cataracts,and glaucoma exhibited heterogeneity both among the families and within the same family.Conclusion In our study,two novel PAX6 mutations associated with aniridia were identified in Chinese families,which expanded the phenotypic and genotypic spectrum of PAX6 mutations.We also analyzed the clinical characteristics of PAX6 haplotype deficiency in Chinese aniridia families.

Black diaphragm intraocular lens implantation and penetrating keratoplasty in aphakic eyes with traumatic aniridia

AIM:To evaluate the long-term outcome of implantation of black diaphragm intraocular (BDI) lens combined with penetrating keratoplasty (PKP) for managing aphakic eyes with traumatic aniridia and corneal damage. METHODS: Six aphakic eyes of six patients with traumatic aniridia and corneal damage had BDI lens implantation at Qingdao Eye Hospital, Shandong Eye Institute from June 2008 to November 2011. Medical records of the patients were reviewed. Three patients received PKP and after 12-18months were implanted with BDI lens. The other three patients completed PKP and BDI lens implantation at the same time. The corrected visual acuity, intraocular pressure and number of corneal endothelial cells were monitored. RESULTS: The patients were followed up for an average of 24.3 ±12.1months (range 14-48 months). All BDI lenses were located well. The best corrected visual acuity got improved in 5 patients (0.1-1.0) and decreased in 1 patient from 0.4 to 0.2. Three patients had normal intraocular pressure (IOP) after implantation. Two patients required antiglaucoma medications to control IOP within the normal range and 1 patient implanted Ahmed glaucoma valve to control IOP. The corneal grafts kept transparent in all eyes and the corneal endothelial counting 】1 000/mm2 , although two patients experienced acute graft rejection and loss more than 30% corneal endothelial cells.CONCLUSION: Implantation of BDI lens combined with PKP is an effective option for managing aphakic eyes with traumatic aniridia and corneal damage. Although the results in our study are encouraging, additional studies of the long -term safety and efficacy are required. Alarger study population and longer follow-up may be beneficial.

Clinical Manifestation of Congenital Aniridia in Indonesia

Background: Congenital aniridia is a rare, panophthalmic disorder that can cause vision loss. Knowledge of aniridia as an isolated ocular abnormality or as a part of systemic abnormalities is important. Management of congenital aniridia should be carried out comprehensively based on it. Objective: To describe clinical features and management of congenital aniridia in a top referral eye hospital in Indonesia. Methods: A retrospective study involving 43 eyes of 22 children (younger than 18 years) diagnosed with congenital aniridia from 2013 to 2018. A detailed history was taken and a complete ophthalmic examination and a systemic examination were performed as required. Clinical characteristics associated with ocular and systemic manifestation and its management were noted. Results: Mean age of patients was 7.6 ± 5.2 years (range 0 - 17 years). Most cases were female (55%) and sporadic (77%). Twenty-one (96%) patients had bilateral involvement at presentation. Foveal hypoplasia was found in 36 eyes (84%), followed by cataract in 26 eyes (61%) and secondary glaucoma in 13 eyes (30%). Nine patients (43%) with cataract had cataract surgery performed. Only 1 patient (5%) with secondary glaucoma underwent filtration surgery. All patients had moderate to severe visual impairment and low vision aid was considered. Regarding its systemic manifestation, none of the patients was diagnosed with an abnormality in the abdomen. Conclusion: There were various ocular features associated with congenital aniridia. Understanding the clinical characteristic and its management could improve the quality of vision in aniridia patients.

ABNORMALITIES OF ERG IN CONGENITAL ANIRIDIA

Congenital aniridia is generally associated with nystagmus, corneal pannus, cataract, ectopia lentis, glaucoma, macular hypoplasia, optic nerve hypoplasia and compromised visual function. Many theories have been proposed, including a failure in the development of the neural ectoderm and/or an aberrant development of mesoderm. We observed the ERG from 19 patients with congenital aniridia. Fourteen patients had abnormal ERG, including the reduced a wave trough under dark adapted red stimuli with dark adap...

Management of Post-traumatic Aniridia with Retinal Detachment

Purpose: To reconstruct the anatomic and functional impairment in patients with post-traumatic aniridia, aphakia, and retinal detachment. Methods: Four patients with unilateral aniridia and aphakia as well as retinal detachment as results of severe eye injuries underwent scleral buckling, vitrectomy, membrane peeling, endolaser photocoagulation, silicone oil or gas temponade, combined with iris diaphragm-IOL implantation. Results: All four patients achieved successfully anatomic and functional reconstruction after surgery. During five to 22 months postoperative follow-up, all retinas remained attached. The final visual acuity increased from finger counting to 0.1 ～ 0.3. Conclusions: The combination of vitreoretinal surgery and iris diaphrgm-IOL implantation is an effective method for post-traumatic aniridia, aphakia and traumatic retinal detachment. It could ameliorate photophobia and improve the biocular vision.Furthermore, artificial iris diaphragm implantation could prevent silicone oil-endothelia contact and salvage silicone keratopathy. Eye Science 2001; 17:35 ～ 38.

Mutation analysis of PAX6 gene in a large Chinese family with aniridia

Background Mutations in PAX6 gene have been shown to be the genetic cause of aniridia, which is a severe panocular eye disease characterised by iris hypoplasia. However, there is no study to do genetic analysis of aniridia, although there are several case reports in China. Here, we describe a mutation analysis of PAX6 in a large Chinese family with aniridia. Methods Genomic DNA from venous blood samples was prepared. Haplotype analysis was performed with two genetic markers ( D11S904 and D11S935). Fourteen exons of the PAX6 gene were amplified from genomic DNA. Polymerase chain reaction ( PCR) products of each exon were analysed by single strand conformational polymorphism (SSCP). The PCR products having an abnormal pattern were sequenced to confirm the mutation. Results Significant evidence for allele sharing in affected patients was detected suggesting that PAX6 mutation links to aniridia in this family. An extra band corresponding to exon 9 in PAX6 was found by single strand conformational polymorphism analysis in all the aniridia patients in this family, but not detected in the unaffected members. A mutation of C to T was detected by sequencing at the nucleotide 1080 that converts the Arg codon (CGA) to the termination codon (TGA). Conclusions Aniridia is caused by a nonsense mutation of PAX6 gene in the large Chinese kindred. Genetic test is important to prevent the transmission of aniridia to their offsprings in the kindred by prenatal diagnosis.

Analysis of PAX6 gene in a Chinese aniridia family

Aniridia is a dominantly inherited eye anomaly characterized by the near or complete absence of the iris with an incidence of approximately 1：80 000.1 Other ocular complications include glaucoma, cataract, and optic nerve hypoplasia. Aniridia can occur by itself, showing an autosomal dominant inheritance, or as part of the WAGR syndrome （Wilm＇s tumor, aniridia, genitourinary abnormalities, and mental retardation）.2 The PAX6 gene, a transcriptional regulator, is of high homology in many kinds of animal, which involves in ocular morphogenesis3 and responsible for aniridia.＂ It is located on chromosome 11p13 and consists of 14 exons with the initiation codon in exon 4 and the termination codon in exon 13. The PAX6 protein has an unusual structure with two DNA-binding domains,

先天性无虹膜1家系临床特征及基因检测分析

目的分析先天性无虹膜1家系遗传学特点,了解PAX6基因突变特点及临床表型的差异。方法收集该家系的病史及临床资料,进行全外显子基因测序检查及数据分析,应用同源建模服务器SWISS-MODEL构建对应的蛋白质模型进行分析。结果本家系中4名发病者均因虹膜缺失存在畏光、睁眼困难症状,相同临床表型为无虹膜、白内障、黄斑中心凹发育不良,还存在个体差异表型。基因检测结果显示:4名发病者均为PAX6基因上c.442_452del:p.M148Afs*48的杂合缺失移码变异,该变异在物种间高度保守。同源建模结果提示突变的PAX6基因最终导致蛋白质构象发生差异变化。结论新发现的PAX6基因变异在发病的家系成员中表型不完全相同,通过同源建模分析增加了对PAX6异常表达导致蛋白质结构异常的认识,遗传学检查可对该家系提供遗传学证据。

PAX6新发移码和无义变异导致中国先天性无虹膜病一家系临床表型和基因型分析

目的分析先天性无虹膜病一家系的临床表现及其致病原因,并分析候选变异对蛋白结构的影响。方法采用家系调查研究方法,收集2023年6月于河南省立眼科医院就诊的中国河南地区汉族先天性无虹膜病一家系2代3人的临床资料,其中患者1例。详细询问患者及其家系成员病史,并进行全面眼科检查,包括视力、眼压、眼前节照相、彩色眼底照相、超声生物显微镜、光学相干断层扫描等。采集该家系成员外周血,对患者进行全外显子组测序,其他成员采用Sanger测序验证。对新发现的变异位点进行致病性和蛋白结构分析。结果先证者男,23岁,双眼视力较差、无虹膜、角膜变性、晶状体轻度混浊、前房较浅且眼压高、周边视网膜变性、黄斑发育不良。先证者父母临床表型未见明显异常。全外显子组测序显示,PAX 6基因外显子10存在移码和无义变异c.734_735del(p.Arg245Asnfs*20),该变异为第734~735位碱基缺失,导致其245位精氨酸变异为天冬酰胺,并在其后19个氨基酸处提前出现终止密码子。该变异在HGMD、Clinvar、千人基因组和gnomAD数据库均未见收录。先证者父母未携带该变异,符合家系共分离。通过SMART工具进行亚结构鉴定发现该变异位于HOX结构域中。氨基酸保守性分析发现PAX 6基因翻译的氨基酸序列第245位精氨酸在人、小家鼠、家犬、非洲爪蟾、猕猴等物种中高度保守。经ACMG《序列变异解读标准和指南》评估,该变异被分类为致病性变异(PVS1+PS2+PM2+PP3)。蛋白结构分析显示,PAX6蛋白的同源结构域和富含脯氨酸-丝氨酸-苏氨酸的结构域缺失。结论PAX 6基因新发移码和无义致病性变异c.734_735del(p.Arg245Asnfs*20)是该先天性无虹膜病家系的致病变异位点,该变异使PAX6蛋白同源结构域和富含脯氨酸-丝氨酸-苏氨酸的结构域缺失。

家族性先天性无虹膜合并白内障患者晶状体前囊膜异常的临床病理学研究

目的:观察先天性无虹膜家系并发白内障患者的晶状体前囊膜的病理学变化,探讨晶状体前囊膜变薄,变脆的病理学机制及对手术方案的意义。方法:收集家族性先天性无虹膜并发白内障患者术中的晶状体前囊膜或晶状体,分别进行光镜和电镜检查。结果:家族性先天性无虹膜合并白内障患者的晶状体前囊膜明显脆弱、变薄。光镜和电镜见晶状体上皮细胞呈变性、坏死、脱失,致使上皮细胞层不连续;有的病例晶状体上皮细胞局灶性增生、复层化;前囊膜表层板层结构均变薄甚至消失。结论:晶状体上皮细胞的退行性和增殖性改变可能是导致先天性无虹膜合并白内障患者的晶状体前囊膜变薄、囊膜的脆弱性增加的原因。提高对前囊膜脆弱性的认识,有助于减少术中囊膜的并发症,达到安全的手术结果。

遗传性先天无虹膜患者的PAX6基因新突变(c．1286del C)

为了研究遗传性先天无虹膜(Hereditary congenital aniridia)患者发病的分子遗传学机制,采用PCR扩增PAX6基因编码区的11个外显子(exon4-13)及外显子和内含子相连接的区域、PCR产物直接测序的方法对1个遗传性先天无虹膜家系的所有成员进行了遗传突变分析。结果表明,在家系中两个患者的PAX6基因exon11均存在c.1286delC新突变。此单个碱基的缺失造成了移码突变,导致肽链自309位氨基酸开始产生一段含55个氨基酸的异常肽段,并产生提前终止密码子(Premature termination codon,PTC),使PAX6蛋白羧基端的59个氨基酸缺失。另外,通过PCR-RFLP分析的方法对家系中所有正常成员和50名中国汉族健康对照个体基因组DNA进行分析均未检测到该突变。

先天性无虹膜患者Pax6基因突变筛查

背景 先天性无虹膜是一种罕见的先天性常染色体显性遗传疾病,表现为双眼无虹膜,目前已知配对盒基因6（Pax6）突变与先天性无虹膜相关. 目的 对先天性无虹膜患者进行Pax6基因突变筛查.方法 纳入2012年8月至2015年10月在天津市眼科医院就诊的先天性无虹膜患者11例,包括来自3个先天性无虹膜家系的6例患者及5例散发病例,所有患者均接受常规眼科检查.采集所有患者的外周静脉血各3 ml,按照DNA分离试剂盒说明书描述的标准流程提取DNA,对Pax6和Elp4基因全部外显子、外显子5＇和3＇端与内含子拼接部序列、SIMO序列进行PCR扩增,采用Sanger直接测序法以及多重连接探针扩增技术（MLPA）对患者的Pax6基因进行序列分析,并与500例无眼前节异常的眼外伤患者的测序结果进行比对.结果 所有患者均虹膜缺如,视力为手动/眼前,1例患者存在晶状体脱位.直接测序结果发现,AN-01家系中的3例患者均携带Pax6基因c.688g＞t（p.E230X）突变,5例散发病例中3例携有Pax6基因突变,分别为c.468g＞a（p.W156X）、c.613c＞t（p.Q205X）和c.141＋2t＞c突变,其中c.688g＞t （pE230X）为新发现的突变.AN-02家系的1例患者、AN-03家系的2例患者及另2例散发病例经直接测序和MLPA验证,均未发现Pax6、Elp4基因以及SIMO片段的突变.500名正常个体均未发现上述突变.结论 先天性无虹膜可由Pax6基因突变引起,c.688g＞t（p.E230X）为新发现的Pax6突变体,扩大了Pax6基因突变谱.

PAX6基因突变至先天性无虹膜一家系的临床相关性研究

目的探讨PAX6基因突变引起先天性无虹膜症眼部及全身疾病发病的规律。方法对家系成员进行详细的视力检查、裂隙灯检查、前房角检查、眼底检查及眼压测量;应用核磁共振(MRI)技术对该家系的18例带有PAX6突变基因的患者和家系中6名正常人及人群中与该家系年龄段匹配的正常人进行脑部结构的扫描和应用CT技术进行脑结构的扫描;口服葡萄糖耐受实验;家系所有成员及与家系中患者年龄相当的对照组人员,空腹12 h以上,抽取静脉血6 mL,口服葡萄糖75 g后分别抽取0.5 h和2 h的静脉血各6 mL,分离血清,对所有血样测定葡萄糖水平。家系成员进行鼻内窥镜检查和CT扫描。结果该家系患者除无虹膜外,还合并多种眼部疾病,随年龄增长眼部并发症逐渐增多,视力逐渐下降甚至失明;家系大部分患者表现有不同程度的脑部结构异常,且年龄越小的患者其胼胝体的变性萎缩越轻,随年龄增长胼胝体的变性萎缩加重;该家系中所有30岁以上的患者均有不同程度的糖耐量异常甚至糖尿病;该家系患者有鼻结构异常或鼻窦炎,患病率明显高于正常人群。结论PAX6基因突变所致先天性无虹膜症不是独立的眼科疾病,而是以无虹膜为首发症状,同时合并多种全身疾病的一种综合征。

无虹膜眼人工晶状体植入术

目的 探讨无虹膜眼人工晶状体植入的手术方法,并评价其疗效。方法 对46例(47眼)无虹膜眼行人工晶状体植入术。其中外伤性白内障42眼,先天性白内障5眼。手术方式:晶状体玻璃体切除人工晶状体睫状沟缝线固定术、囊袋内人工晶状体植入术、带虹膜隔人工晶状体植入术及联合穿透性角膜移植术。随访1-14月,平均4.8月。结果 47眼手术顺利,术后人工晶状体位置正。术后矫正视力≥0.5者33眼(70.21％),0.1-0.4者12眼(25.56％);术后4眼眼压升高,10眼前房纤维蛋白渗出。无严重远期并发症。结论 无虹膜眼人工晶状体植入是可行的,但患者眼部情况复杂,应根据眼部具体情况选择手术方式和人工晶状体的类型。影响术后视力恢复的主要因素是散光。

先天性无虹膜患者中央角膜厚度异常分析

目的测量先天性无虹膜患者与正常人的中央角膜厚度,分析差异存在可能的原因。方法选取2008-2009年我院7名确诊为先天性无虹膜患者(14只眼),通过角膜内皮镜观察角膜内皮细胞的形态和密度,通过超声角膜测厚仪测量中央角膜的厚度,50只正常眼做对照。结果患者的平均中央角膜厚度为(645±32.8)μm,正常人为(552±35.6)μm,无虹膜患者的平均中央角膜厚度明显高于正常人,差异有统计学意义(P<0.01);角膜内皮镜检查显示无虹膜患者角膜内皮细胞均正常。结论先天性无虹膜患者的中央角膜厚度明显增加,中央角膜厚度的增加与角膜内皮细胞无关;对于无虹膜患者进行眼压测量,结果会过高估计眼压。

应用带虹膜人工晶状体植入术治疗外伤性无虹膜无晶状体眼

目的应用带虹膜人工晶状体植入术治疗外伤性无虹膜无晶状体眼，以解决患者严重的畏光症状，并矫正视力。方法引进德国Morcher公司生产的带虹膜人工晶状体，为6例外伤性无虹膜无晶状体眼施行二期人工晶状体缝线固定术。结果术后患者畏光症状明显改善，视力有不同程度提高。结论带虹膜人工晶状体植入术用于治疗外伤性无虹膜无晶状体眼，实用有效，具有良好的应用推广前景，但术后并发症值得注意。

PAX6基因在一先天性无虹膜家系中的突变筛查

目的研究PAX6基因突变是否是导致一先天性无虹膜家系致病的原因。方法收集一先天性无虹膜家系,制备外周血基因组DNA,PCR扩增PAX6基因的外显子及其邻近的内含子,应用单链构象多态性(SSCP)法检测,如果发现变异条带,将相应的扩增产物回收并纯化后进行PAX6基因测序。测序结果与GenBank公布的PAX6基因正常序列比对,寻找有无突变。结果本家系43名成员中有8例患病,遗传方式符合常染色体显性遗传特点,40岁以上的4例患者眼压高于35mmHg。所有患者中未发现全身并发症。在家系所有患者中均未发现异常条带。结论 PAX6基因与该先天性无虹膜家系无关。该家系的致病基因有待进一步通过全基因组扫描的方法来确定。

先天性无虹膜家系Pax6基因的突变研究

目的对一先天性无虹膜症家系的致病基因Pax6基因进行突变检测分析。方法对该家系进行家系调查及外周血样本采集,Pax6基因全部外显子测序,使用美国ABIPRISMTM377XLDNA自动测序仪,应用双脱氧末端终止法进行序列分析;用MspI进行突变鉴定。结果该家系共5代58人,患病21例,采集血样28人份,测序结果发现Pax6基因R254X(760C>T)突变。结论先天性无虹膜症的遗传方式为常染色体显性遗传,呈高度临床及遗传异质性,无义突变R254X(760C>T)为一新突变。

糖尿病合并先天性无虹膜症家系存在PAX6基因无义突变

目的探讨1个糖尿病合并无虹膜症家系成员的基因缺陷及其临床特点。方法收集1个糖尿病合并无虹膜症家系的4名患者和2名健康亲属的外周血标本,提取基因组DNA,针对人类配对盒基因（PAX6）4-13外显子设计引物,采用聚合酶链反应结合直接测序法（PCR-Sequencing）分析PAX6基因编码序列有无异常。结果在糖尿病和糖耐量异常合并无虹膜症患者中发现PAX6基因Arg240X杂合无义突变。结论 PAX6基因Arg240X无义突变可能通过影响胰岛素基因的转录,导致胰岛素分泌减少所致的糖代谢异常,同时也可能导致先天性遗传性无虹膜症的发生。