Leber先天性黑蒙临床与GUCY2D基因突变分析

目的 分析Leber先天性黑蒙的临床特点及其候选基因变异情况。方法 连续收集分析27例年龄4mo-18a的Leber先天性黑蒙先证者临床资料,应用PCR-异源双链-SSCP法分析GUCY2D基因外显子2和8,寻找可能的变异结果 27例患者均在2a以内出现视力差或对光、物体无反应,最最好视力小于0.1。症状年龄21例在3mo内,27例均有眼球震颤（其中15例为眼球扫视运动）,22例有眼底异常,5例眼底未见异常,3例有家族史并呈常染色体隐性遗传,ERG锥杆反应重度下降或记录不到波,未发现GUCY2D基因突变。结论 Leber先天 性黑蒙临床表现多样,诊断有赖于ERG。本组病例可能与GUCY2D外显子2、8突变无关。     

RPE65 Mutations in Two Japanese Families with Leber Congenital Amaurosis

Purpose: To investigate genetic and clinical features of patients with Leber congenital amaurosis (LCA) caused by RPE65 mutations.

Methods: Five Japanese families with LCA were recruited. We performed complete ophthalmic examinations, with optical coherence tomography, fundus autofluorescence imaging, and full-field electroretinography (ERG). Genetic analysis was performed with whole-exome sequencing analysis and Sanger sequencing.

Results: We identified RPE65 mutations in two unrelated LCA patients from two families. Case 1: A 5-month-old girl was diagnosed with LCA because of nystagmus, loss of vision and non-recordable ERG. She was the only one affected in her non-consanguineous family, and exhibited novel compound heterozygous RPE65 mutations (c.177C>G, p.H59Q and c.183_184insT, p.D62X). Case 2: A 30-year-old woman, who had night blindness and poor ocular pursuit during the first year of life, exhibited severe retinal degeneration and non-recordable ERG. She was the only affected in her non-consanguineous family, and showed a homozygous RPE65 mutation (c.1543C>T, p.R515W).

Conclusions: By using whole-exome sequencing analysis, three RPE65 mutations were identified in two Japanese patients with LCA. This approach would be useful for identification of disease-causing mutations of LCA.     

A high prevalence of biallelic RPE65 mutations in Costa Rican children with Leber congenital amaurosis and early-onset retinal dystrophy

Background: Leber congenital amaurosis (LCA) and early-onset retinal dystrophy (EORD), are primary causes of inherited childhood blindness. Both are autosomal recessive diseases, with mutations in more than 25 genes explaining approximately ~70% of cases. However, the genetic cause for many cases remains unclear. Sequencing studies from genetically isolated populations with increased prevalence of a disorder has proven useful for rare variant studies, making Costa Rica an ideal place to study LCA/EORD genetics.

Materials and Methods: Twenty-eight affected children (25 LCA, three EORD) and their immediate family members, totaling 52 individuals (30 affected) from 22 families, were sequenced. Whole exome sequencing was performed on all affected individuals. Available parents were analyzed either by whole exome sequencing (WES) or Sanger sequencing to determine transmission.

Results: All affected individuals demonstrated compound heterozygous or homozygous mutations in known Inherited Retinal Disease (IRD) associated genes. Twelve variants were identified in at least one individual in three genes, RDH12, RPE65, and USH2A. Four recurrent RPE65 mutations were observed in 97% of individuals and 95% of families. All patients with LCA and two of the three individuals with EORD had biallelic mutations in RPE65; one child with EORD had a homozygous RDH12 mutation.

Conclusions: These data suggest that the majority of LCA/EORD in Costa Rica is due to four founder mutations in RPE65 which have been maintained in this genetically isolated population. This finding is of great clinical significance due to the availability of gene therapy recently approved in the US and European Union for patients with biallelic RPE65 defects.     

LCA2型基因治疗临床试验研究进展

Leber先天性黑矇(Leber''s congenital amaurosis,LCA)是一种遗传性致盲性眼病,在婴儿早期出现严重的视力低下或丧失丧失。该疾病的LCA2型与RPE65的突变相关。既往对于LCA2在内的遗传性视网膜疾病无有效治疗方法。近年来,随着基因治疗技术的进步,遗传性视网膜疾病的治疗进展取得了巨大进步,其中最成功的便是LCA2的基因治疗。本文简要介绍了LCA2基因治疗的发展,并对既往LCA2临床试验中的注射剂型、剂量、注射方式、测量方法、治疗效果与年龄的相关性和治疗效果的稳定性进行综述,为LCA2基因治疗进入我国临床工作提供参考及临床治疗经验。     

Genetic testing for retinal dystrophies and dysfunctions: benefits, dilemmas and solutions

Human retinal dystrophies have unparalleled genetic and clinical diversity and are currently linked to more than 185 genetic loci. Genotyping is a crucial exercise, as human gene-specific clinical trials to study photoreceptor rescue are on their way. Testing confirms the diagnosis at the molecular level and allows for a more precise prognosis of the possible future clinical evolution. As treatments are gene-specific and the 'window of opportunity' is time-sensitive; accurate, rapid and cost-effective genetic testing will play an ever-increasing crucial role. The gold standard is sequencing but is fraught with excessive costs, time, manpower issues and finding non-pathogenic variants. Therefore, no centre offers testing of all currently 132 known genes. Several new micro-array technologies have emerged recently, that offer rapid, cost-effective and accurate genotyping. The new disease chips from Asper Ophthalmics (for Stargardt dystrophy, Leber congenital amaurosis [LCA], Usher syndromes and retinitis pigmentosa) offer an excellent first pass opportunity. All known mutations are placed on the chip and in 4 h a patient's DNA is screened. Identification rates (identifying at least one disease-associated mutation) are currently approximately 70% (Stargardt), approximately 60-70% (LCA) and approximately 45% (Usher syndrome subtype 1). This may be combined with genotype-phenotype correlations that suggest the causal gene from the clinical appearance (e.g. preserved para-arteriolar retinal pigment epithelium suggests the involvement of the CRB1 gene in LCA). As approximately 50% of the retinal dystrophy genes still await discovery, these technologies will improve dramatically as additional novel mutations are added. Genetic testing will then become standard practice to complement the ophthalmic evaluation.     

Leber先天性黑矇六家系临床表现和遗传分析

目的:观察分析Leber先天性黑矇（LCA）致病基因类型及临床表型特征。方法:回顾性临床研究。基因检测确诊的LCA患者6例及其家系成员18名纳入研究。患者分别来自6个无血缘关系家系。采集所有受检者外周静脉血,提取全基因组DNA。应用包含463个致病基因的遗传眼病捕获芯片进行靶向捕获富集高通量测序,对 TUL...     

Comprehensive analysis of genetic variations in strictly-defined Leber congenital amaurosis with whole-exome sequencing in Chinese

AIM: To make a comprehensive analysis of the potential pathogenic genes related with Leber congenital amaurosis (LCA) in Chinese. METHODS: LCA subjects and their families were retrospectively collected from 2013 to 2015. Firstly, whole-exome sequencing was performed in patients who had underwent gene mutation screening with nothing found, and then homozygous sites was selected, candidate sites were annotated, and pathogenic analysis was conducted using softwares including Sorting Tolerant from Intolerant (SIFT), Polyphen-2, Mutation assessor, Condel, and Functional Analysis through Hidden Markov Models (FATHMM). Furthermore, Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of pathogenic genes were performed followed by co-segregation analysis using Fisher exact Test. Sanger sequencing was used to validate single-nucleotide variations (SNVs). Expanded verification was performed in the rest patients. RESULTS: Totally 51 LCA families with 53 patients and 24 family members were recruited. A total of 104 SNVs (66 LCA-related genes and 15 co-segregated genes) were submitted for expand verification. The frequencies of homozygous mutation of KRT12 and CYP1A1 were simultaneously observed in 3 families. Enrichment analysis showed that the potential pathogenic genes were mainly enriched in functions related to cell adhesion, biological adhesion, retinoid metabolic process, and eye development biological adhesion. Additionally, WFS1 and STAU2 had the highest homozygous frequencies. CONCLUSION: LCA is a highly heterogeneous disease. Mutations in KRT12, CYP1A1, WFS1, and STAU2 may be involved in the development of LCA.     

RPGRIP1基因新突变致Leber先天性黑矇一家系

目的确定1个汉族Leber先天性黑矇(LCA)家系的致病基因突变。方法回顾性研究。2018年10月在河南省立眼科医院就诊的LCA一家系1例患者和3名家系成员纳入研究。详细询问患者病史并行物体注视性质、追随试验、裂隙灯显微镜、散瞳验光、眼底照相及全视野ERG检查;家系成员行BCVA、裂隙灯显微镜联合前置镜、验光、眼底照相及全视野ERG检查。采集先证者及其兄长、父母的外周静脉血5 ml,提取全基因组DNA。应用包含441个致病基因的遗传眼病捕获芯片进行靶向捕获富集高通量测序以获得致病基因及突变。对可疑致病突变位点通过Sanger进行验证,并行生物信息学分析确定基因突变位点的致病性。结果患者表现为自幼不追物但有明显畏光和眼球震颤;双眼眼前节及眼底无异常;全视野ERG检查可见双眼视锥、视杆系统功能严重下降。基因检测结果显示,患者RPGRIP1基因存在c.1635dupA和c.3565C>T两个突变。其中,RPGRIP1 c.1635dupA为新发突变。RPGRIP1基因c.1635dupA和c.3565C>T构成复合杂合突变。生物信息学分析结果显示,c.3565C>T为致病突变,c.1635dupA为可能致病突变。结论RPGRIP1基因新发突变c.1635dupA与c.3565C>T构成复合杂合突变可能是本家系的致病原因。     

Leber先天性黑矇患者五种血清离子的异常变化

目的：分析Leber先天性黑矇(Leber congenital amaurosis,LCA)患者血清中镁、钙、钾、钠及氯离子浓度的变化情况。

方法：采用回顾性序列病例研究方法,纳入临床诊断的LCA患者50例,正常对照组99例,按盲法由专业技术人员完成血清离子浓度检查,并分别行LCA组和正常对照组比较。

结果：在LCA患者检测的血清离子浓度中,钙离子浓度和钾离子浓度分别为2.338±0.090mmol/L和4.164±0.356 mmol/L,分别与正常组相比均显著升高(均P<0.05); 镁离子浓度为0.835±0.059mmol/L,与正常组相比显著下降(P<0.05); 其他两种离子血清浓度与正常组相比无统计学差异(均P>0.05)。

结论：LCA患者血清镁、钙和钾离子浓度异常变化应该引起眼科医师的关注,其可能与LCA的发病有关。     

Leber先天性黑矇患者血清脂质浓度的变化

目的：分析Leber先天性黑矇(Leber congenital amaurosis,LCA)患者血清脂质浓度的变化。

方法：采用回顾性序列病例研究方法,选取临床诊断为LCA的患者50例作为LCA组,选取52例正常人作为正常对照组,按盲法由专业技术人员测量两组受检者血清中低密度脂蛋白胆固醇(low density lipoprotein cholesterol,LDL-C)、高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-C)、甘油三酯(triglycerides,TG)、总胆固醇(total cholesterol,TC)含量,并对两组受检者的测量结果进行比较。

结果：LCA患者50例中,血脂水平异常者占46%,其中低HDL-C血症者占26%,高TG血症者占48%,高TC血症者占17%,混合型高脂血症者占9%。LCA患者血清HDL-C浓度为1.221±0.317mmol/L,较正常对照组明显下降,差异有统计学意义(P<0.05); 血清TG浓度(1.377±1.171mmol/L)和TC浓度(4.506±0.694mmol/L)与正常对照组相比均明显升高,差异有统计学意义(均P<0.01); LDL-C浓度与正常对照组相比,差异无统计学意义(P>0.05)。

结论：LCA患者血清HDL-C、TG和TC浓度异常变化可能与LCA的发病相关。     

Analysis of three genes in Leber congenital amaurosis in Indonesian patients

PURPOSE: To assess the frequency, the pattern of disease causing mutations, and phenotypic variations in patients with Leber congenital amaurosis (LCA) from Indonesia. PATIENTS AND METHODS: Twenty-one unrelated index cases with a clinical diagnosis of LCA were screened for mutations in the coding sequence of RetGC1, RPE65 and AIPL1 gene with single strand conformation polymorphism analysis followed by direct sequencing and restriction enzyme digestion. RESULTS: Four novel disease causing mutations were identified: Three in the RPE65 gene (106del9bp, G32V and Y435C) in two of 21 index cases and one in the AIPL1 (K14E). Two of them were homozygous and one was compound-heterozygous. No disease causing mutation was identified in RetGC1. CONCLUSIONS: The four novel disease causing mutations identified in this study confirmed the diagnosis of LCA which has not been recognized before in Indonesia. The frequency of RPE65 mutations was 9.5%; and of AIPL1 mutations 4.8%. This was in general accordance with previous studies reported from other countries. Unlike in those studies, no disease causing RetGC1 mutations could be identified in our patients. Phenotypically, the RPE65 and AIPL1 mutations identified in this study caused nearly total blindness by the second decade of life, but had a different onset of symptoms. The patients with the RPE65 mutations retained some useful visual function until the end of the first decade, which progressed to total blindness during the second decade of life, whereas the (homozygous) AIPL1 mutation was associated with nearly total blindness from infancy on. Therefore, RPE65 mutations have to be considered to cause early onset severe retinal degeneration (EOSRD), and AIPL1 mutations a form of LCA.     

Mutation screening of Pakistani families with congenital eye disorders

To map the disease loci several Pakistani families suffering from autosomal recessive retinitis pigmentosa with preserved para-arteriolar retinal pigment epithelium and Leber congenital amaurosis (LCA) were analyzed. Analysis revealed close genetic linkage between the disease phenotype of some of the families (3330RP, 111RP and 010LCA) and the microsatellite markers on chromosome 1q31. Mutation screening of the candidate gene CRB1 revealed a G to A transversion in exon 7 in arRP family 330RP and a T to C substitution in another arRP family, 111RP. In exon 9 of the CRB1 gene a T to C transversion was found in the family suffering from LCA (010LCA).The LCA phenotype of another family (011LCA) in which the CRB1 locus was excluded, showed linkage with microsatellite markers D17S1294 and D17S796 on chromosome 17p13.1. The association of the candidate gene GUCY2D (17p13.1) with the disease phenotype was excluded as no disease-associated mutation was found in any of its exons. Mutation screening of another candidate gene, AIPL1 located in the same region, showed a novel homozygous C to A substitution in exon 2. These sequence changes are unique for the Pakistani families and some of these have not been reported previously.     

Efficacy of topical brinzolamide in children with retinal dystrophies

ABSTRACT

Background: Inherited retinal dystrophies are a leading cause of irreversible blindness in children in the United States. Topical carbonic anhydrase inhibitors have improved central vision and cystoid macular edema in patients with retinal dystrophies, but few studies have assessed their efficacy in children.

Materials and Methods: A retrospective chart review was performed with Institutional Review Board approval to identify pediatric patients with inherited retinal dystrophies who received topical brinzolamide at a single university center between 2008 and 2015. Serial visual acuity and central macular thicknesses were compared to assess the efficacy of brinzolamide.

Results: Seven subjects were identified who met the inclusion criteria. Four had juvenile X-linked retinoschisis, two had retinitis pigmentosa, and one had Leber congenital amaurosis. All were prescribed brinzolamide thrice daily; however, one patient was completely non-compliant. Four of the six treated patients exhibited a mild decrease in central macular thickness in both eyes during the study with all six treated patients having significantly improved vision at the first endpoint, 33.2 ± 8.2 months after treatment initiation. For treated patients, average visual acuity (LogMAR) ± standard error of the mean improved from 0.5 ± 0.04 pre-treatment to 0.3 ± 0.1 at the second endpoint, 50.2 ± 7.3 months after treatment initiation.

Conclusions: Mild anatomic improvement of macular cysts was seen in pediatric patients using brinzolamide. Visual acuity improvement occurred even without significant reduction in macular cysts. Further studies are needed to determine whether the beneficial effects of carbonic anhydrase inhibitors are sustained in children with inherited retinal degenerations.     

An overview of Leber congenital amaurosis: a model to understand human retinal development

Leber congenital amaurosis is a congenital retinal dystrophy described almost 150 years ago. Today, Leber congenital amaurosis is proving instrumental in our understanding of the molecular events that determine normal and aberrant retinal development. Six genes have been shown to be mutated in Leber congenital amaurosis, and they participate in a wide variety of retinal pathways: retinoid metabolism (RPE65), phototransduction (GUCY2D), photoreceptor outer segment development (CRX), disk morphogenesis (RPGRIP1), zonula adherens formation (CRB1), and cell-cycle progression (AIPL1). Longitudinal studies of visual performance show that most Leber congenital amaurosis patients remain stable, some deteriorate, and rare cases exhibit improvements. Histopathological analyses reveal that most cases have extensive degenerative retinal changes, some have an entirely normal retinal architecture, whereas others have primitive, poorly developed retinas. Animal models of Leber congenital amaurosis have greatly added to understanding the impact of the genetic defects on retinal cell death, and response to rescue. Gene therapy for RPE65 deficient dogs partially restored sight, and provides the first real hope of treatment for this devastating blinding condition.     

Long term follow-up of a family with GUCY2D dominant cone dystrophy

AIM: To describe long term follow-up in a family with GUCY2D dominant cone dystrophy. METHODS: Optical coherence tomography scans and fundus autofluorescence images were obtained. Flash and pattern electroretinograms (ERGs) and occipital pattern reversal visual evoked potentials were recorded. RESULTS: Two members of the same family (father and son) were identified to have the heterozygous R838C mutation in the GUCY2D gene. The father presented at the age of 45 with bilateral bull’s eye maculopathy and temporal disc pallor. Over 13y of serial follow up visits, the bull’s eye maculopathy progressed gradually into macular atrophy. Electrophysiological tests were significantly degraded suggesting poor macular function. Spectral-domain optical coherence tomography (SD-OCT) scans showed progressive loss and disruption of the ellipsoid layer at the foveal level. His son presented at the age of 16 with bilateral granular retinal pigment epithelial changes in both maculae. Electrophysiological testing was initially borderline normal but has gradually deteriorated to show reduced cone ERGs and macula function. SD-OCT demonstrated gradual macular thinning and atrophy bilaterally. Unlike his father, there was no disruption of the ellipsoid layer. CONCLUSION: Both family members exhibited gradual changes in their fundi, electrophysiological testing and multimodal imaging. Changes were milder than those observed in other mutations of the same gene.     

Detailed functional and structural phenotype of Bietti crystalline dystrophy associated with mutations in CYP4V2 complicated by choroidal neovascularization

Purpose: To describe in detail the phenotype of a patient with Bietti crystalline dystrophy (BCD) complicated by choroidal neovascularization (CNV) and the response to intravitreal Bevacizumab (Avastin^®; Genentech/Roche).

Methods: A 34-year-old woman with BCD and mutations in CYP4V2 (c.802-8_806del13/p.H331P:c992A>C) underwent a complete ophthalmic examination, full-field flash electroretinography (ERG), kinetic and two-color dark-adapted perimetry, and dark-adaptometry. Imaging was performed with spectral domain optical coherence tomography (SD-OCT), near infrared (NIR) and short wavelength (SW) fundus autofluorescence (FAF), and fluorescein angiography (FA).

Results: Best-corrected visual acuity (BCVA) was 20/20 and 20/60 for the right and left eye, respectively. There were corneal paralimbal crystal-like deposits. Kinetic fields were normal in the peripheral extent. Retinal crystals were most obvious on NIR-reflectance and corresponded with hyperreflectivities within the RPE on SD-OCT. There was parafoveal/perifoveal hypofluorescence on SW-FAF and NIR-FAF. Rod > cone sensitivity loss surrounded fixation and extended to ~10° of eccentricity corresponding to regions of photoreceptor outer segment-retinal pigmented epithelium (RPE) interdigitation abnormalities. The outer nuclear layer was normal in thickness. Recovery of sensitivity following a ~76% rhodopsin bleach was normal. ERGs were normal. A subretinal hemorrhage in the left eye co-localized with elevation of the RPE on SD-OCT and leakage on FA, suggestive of CNV. Three monthly intravitreal injections of Bevacizumab led to restoration of BCVA to baseline (20/25).

Conclusion: crystals in BCD were predominantly located within the RPE. Photoreceptor outer segment and apical RPE abnormalities underlie the relatively extensive retinal dysfunction observed in relatively early-stage BCD. Intravitreal Bevacizumab was effective in treating CNV in this setting.     

Progress in treating inherited retinal diseases: Early subretinal gene therapy clinical trials and candidates for future initiatives

Due to improved phenotyping and genetic characterization, the field of ‘incurable’ and ‘blinding’ inherited retinal diseases (IRDs) has moved substantially forward. Decades of ascertainment of IRD patient data from Philadelphia and Toronto centers illustrate the progress from Mendelian genetic types to molecular diagnoses. Molecular genetics have been used not only to clarify diagnoses and to direct counseling but also to enable the first clinical trials of gene-based treatment in these diseases. An overview of the recent reports of gene augmentation clinical trials by subretinal injections is used to reflect on the reasons why there has been limited success in this early venture into therapy. These first-in human experiences have taught that there is a need for advancing the techniques of delivery of the gene products - not only for refining further subretinal trials, but also for evaluating intravitreal delivery. Candidate IRDs for intravitreal gene delivery are then suggested to illustrate some of the disorders that may be amenable to improvement of remaining central vision with the least photoreceptor trauma. A more detailed understanding of the human IRDs to be considered for therapy and the calculated potential for efficacy should be among the routine prerequisites for initiating a clinical trial.