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Purpose: Despite numerous recent advances in retinal gene therapy using adeno-associated viruses (AAVs) as delivery vectors, there remains a crucial need to identify viral vectors with the ability to transduce specific retinal cell types and that have a larger carrying capacity than AAV. In this study, we evaluate the retinal tropism of 2 chimeric helper-dependent adenoviruses (HDAds), helper-dependent adenovirus serotype 5 (HDAd5)/3 and HDAd5/35, both ex vivo using human retinal explants and in vivo using rats. Methods: We transduced cultured human retinal explants with HDAd5/3 and HDAd5/35 carrying an eGFP vector and evaluated tropism and transduction efficiency using immunohistochemistry. To assess in vivo transduction efficiency, subretinal injections were performed in wild-type Sprague-Dawley rats. For both explants and subretinal injections, we delivered 10 μL (1 × 10(6) vector genomes/mL) and assessed tropism at 7- and 14-days post-transduction, respectively. Results: HDAd5/3 and HDAd5/35 both transduced human retinal ganglion cells (RGCs) and Müller cells, but not photoreceptors, in human retinal explants. However, subretinal injections in albino rats resulted in transduction of the retinal pigmented epithelium only, highlighting species-specific differences in retinal tropism and the value of a human explant model when testing vectors for eventual human gene therapy. Conclusions: Chimeric HDAds are promising candidates for the delivery of large genes, multiple genes, or neuroprotective factors to Müller cells and RGCs. These vectors may have utility for targeted therapy of neurodegenerative diseases primarily involving retinal ganglion or Müller cell types, such as glaucoma or macular telangiectasia type 2.

PURPOSE: The Faroe Islands are home to 50,000 genetically isolated people in the North Atlantic. The prevalence of open-angle glaucoma (OAG) in the Faroese population is unknown. Consequently, we conducted a survey to determine the prevalence of OAG in the Faroese population. We also investigated the role of known glaucoma-causing genes in Faroese OAG.MATERIALS AND METHODS: We conducted a prospective survey of known and newly diagnosed glaucoma patients at the Faroese National Hospital, Landssjukrahusid, Tórshavn between October 1, 2015 to December 31, 2017. In addition we reviewed the only eye care provider in the Faroese Islands by scrutinizing electronic medical records between 2009 and June 15, 2014, October 1, 2015 and the partly overlapping prescriptions for ocular hypotensive medications in 2016 to identify patients with either a diagnosis of glaucoma, a diagnosis of ocular hypertension or a prescription for ocular hypotensive medications. Next, we prospectively confirmed diagnoses with complete eye examinations. Patient DNA samples were tested for variations in known glaucoma-causing genes [myocilin (MYOC), optineurin (OPTN), and TANK binding kinase 1 (TBK1)].RESULTS: We determined the age-related prevalence of OAG January 1, 2017 in individuals 40 years or older to be 10.7/1000 (1.07%) and highly age-related. A diagnosis of OAG was present in 264 patients, of whom 211 (79.9%) had primary OAG (including normal tension glaucoma), 49 (18.6%) had pseudoexfoliation glaucoma, and 4 (1.5%) had pigmentary glaucoma. Among patients receiving medications for glaucoma, nearly 50% had primary OAG, while the majority of the rest had ocular hypertension or secondary glaucoma. No disease-causing variants were detected in MYOC, OPTN, or TBK1.CONCLUSIONS: The calculated prevalence of OAG in the Faroe Islands was 1.07%. The absence of MYOC, OPTN, or TBK1 disease-causing variants in Faroese primary OAG patients suggests that a different, potentially unique set of genes may be contributing to the pathogenesis of glaucoma in this population.

The standardization of variant curation criteria is essential for accurate interpretation of genetic results and clinical care of patients. The variant curation guidelines developed by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) in 2015 are widely used but are not gene specific. To address this issue, the Clinical Genome Resource (ClinGen) Variant Curation Expert Panels (VCEP) have been tasked with developing gene-specific variant curation guidelines. The Glaucoma VCEP was created to develop rule specifications for genes associated with primary glaucoma, including myocilin (MYOC), the most common cause of Mendelian glaucoma. Of the 28 ACMG/AMP criteria, the Glaucoma VCEP adapted 15 rules to MYOC, and deemed 13 rules not applicable. Key specifications included determining minor allele frequency thresholds, developing an approach to counting probands and segregations, and reviewed functional assays. The rules were piloted on 81 variants and led to a change in classification in 38% of those that were classified in ClinVar with functional evidence influencing the classification of 18 variants. The standardized variant curation guidelines for MYOC provide a framework for the consistent application of the rules between laboratories, to improve MYOC genetic testing in the management of glaucoma.

Purpose To characterize the visual pathway integrity of five glaucoma animal models using diffusion tensor imaging (DTI). Methods Two experimentally induced and three genetically determined models of glaucoma were evaluated. For inducible models, chronic IOP elevation was achieved via intracameral injection of microbeads or laser photocoagulation of the trabecular meshwork in adult rodent eyes. For genetic models, the DBA/2J mouse model of pigmentary glaucoma, the LTBP2 mutant feline model of congenital glaucoma, and the transgenic TBK1 mouse model of normotensive glaucoma were compared with their respective genetically matched healthy controls. DTI parameters, including fractional anisotropy, axial diffusivity, and radial diffusivity, were evaluated along the optic nerve and optic tract. Results Significantly elevated IOP relative to controls was observed in each animal model except for the transgenic TBK1 mice. Significantly lower fractional anisotropy and higher radial diffusivity were observed along the visual pathways of the microbead- and laser-induced rodent models, the DBA/2J mice, and the LTBP2-mutant cats compared with their respective healthy controls. The DBA/2J mice also exhibited lower axial diffusivity, which was not observed in the other models examined. No apparent DTI change was observed in the transgenic TBK1 mice compared with controls. Conclusions Chronic IOP elevation was accompanied by decreased fractional anisotropy and increased radial diffusivity along the optic nerve or optic tract, suggestive of disrupted microstructural integrity in both inducible and genetic glaucoma animal models. The effects on axial diffusivity differed between models, indicating that this DTI metric may represent different aspects of pathological changes over time and with severity.

Purpose: Aniridia is a rare congenital eye disease, characterized by a constellation of symptoms including hypoplastic irides, foveal hypoplasia, early cataract, corneal stem cell deficienc...

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders.Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma.Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma.Exposures: Genetic variants associated with primary open-angle glaucoma.Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10−8 in the discovery stage and in the meta-analysis of combined discovery and validation data.Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10−8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10−13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry.Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.

Background Glaucoma is a leading cause of visual disability and blindness. Release of iris pigment within the eye, pigment dispersion syndrome (PDS), can lead to one type of glaucoma known as pigmentary glaucoma. PDS has a genetic component, however, the genes involved with this condition are largely unknown. We sought to discover genes that cause PDS by testing cohorts of patients and controls for mutations using a tiered analysis of exome data. Results Our primary analysis evaluated melanosome-related genes that cause dispersion of iris pigment in mice (TYRP1, GPNMB, LYST, DCT, and MITF). We identified rare mutations, but they were not statistically enriched in PDS patients. Our secondary analyses examined PMEL (previously linked with PDS), MRAP, and 19 other genes. Four MRAP mutations were identified in PDS cases but not in controls (p = 0.016). Immunohistochemical analysis of human donor eyes revealed abundant MRAP protein in the iris, the source of pigment in PDS. However, analysis of MRAP in additional cohorts (415 cases and 1645 controls) did not support an association with PDS. We also did not confirm a link between PMEL and PDS in our cohorts due to lack of reported mutations and similar frequency of the variants in PDS patients as in control subjects. Conclusions We did not detect a statistical enrichment of mutations in melanosome-related genes in human PDS patients and we found conflicting data about the likely pathogenicity of MRAP mutations. PDS may have a complex genetic basis that is not easily unraveled with exome analyses.

The extracellular matrix (ECM) plays a crucial role in all parts of the eye, from maintaining clarity and hydration of the cornea and vitreous to regulating angiogenesis, intraocular pressure maintenance, and vascular signaling. This review focuses on the interactions of the ECM for homeostasis of normal physiologic functions of the cornea, vitreous, retina, retinal pigment epithelium, Bruch’s membrane, and choroid as well as trabecular meshwork, optic nerve, conjunctiva and tenon’s layer as it relates to glaucoma. A variety of pathways and key factors related to ECM in the eye are discussed, including but not limited to those related to transforming growth factor-β, vascular endothelial growth factor, basic-fibroblastic growth factor, connective tissue growth factor, matrix metalloproteinases (including MMP-2 and MMP-9, and MMP-14), collagen IV, fibronectin, elastin, canonical signaling, integrins, and endothelial morphogenesis consistent of cellular activation-tubulogenesis and cellular differentiation-stabilization. Alterations contributing to disease states such as wound healing, diabetes-related complications, Fuchs endothelial corneal dystrophy, angiogenesis, fibrosis, age-related macular degeneration, retinal detachment, and posteriorly inserted vitreous base are also reviewed.

Background Changes in choroidal thickness are associated with various ocular diseases, and the choroid can be imaged using spectral-domain optical coherence tomography (SD-OCT) and enhanced depth imaging OCT (EDI-OCT). New method Eighty macular SD-OCT volumes from 80 patients were obtained using the Zeiss Cirrus machine. Eleven additional control subjects had two Cirrus scans done in one visit along with enhanced depth imaging (EDI-OCT) using the Heidelberg Spectralis machine. To automatically segment choroidal layers from the OCT volumes, our graph-theoretic approach was utilized. The segmentation results were compared with reference standards from two independent graders, and the accuracy of automated segmentation was calculated using unsigned/signed border positioning/thickness errors and Dice similarity coefficient (DSC). The repeatability and reproducibility of our choroidal thicknesses were determined by intraclass correlation coefficient (ICC), coefficient of variation (CV), and repeatability coefficient (RC). Results The mean unsigned/signed border positioning errors for the choroidal inner and outer surfaces are 3.39 ± 1.26 µm (mean ± standard deviation)/− 1.52 ± 1.63 µm and 16.09 ± 6.21 µm/4.73 ± 9.53 µm, respectively. The mean unsigned/signed choroidal thickness errors are 16.54 ± 6.47 µm/6.25 ± 9.91 µm, and the mean DSC is 0.949 ± 0.025. The ICC (95% confidence interval), CV, RC values are 0.991 (0.977–0.997), 2.48%, 14.25 µm for the repeatability and 0.991 (0.977–0.997), 2.49%, 14.30 µm for the reproducibility studies, respectively. Comparison with existing method(s) The proposed method outperformed our previous method using choroidal vessel segmentation and inter-grader variability. Conclusions This automated segmentation method can reliably measure choroidal thickness using different OCT platforms.

Background Nanophthalmos has a significant genetic background and disease-causing mutations have been recently been reported in the myelin regulatory factor (MYRF) gene. We report clinical features in a patient with nanophthalmos and a Thr518Met MYRF mutation. Case presentation A three-year-old male was discovered to have nanophthalmos after first presenting to the emergency department for a frontal headache, eye pain, emesis, and lethargy. Imaging studies (CT and MRI) were negative except for increased posterior fossa cerebrospinal fluid. Subsequent examinations revealed nanophthalmos (short axial eye lengths 18.1 mm OD and 18.3 mm OS), microcornea, and a large crystalline lens. Peripheral chorioretinal pigment abnormalities were also observed. He experienced episodes of marked ocular hypertension (53 mmHg OD and 60 mmHg) likely due to intermittent angle closure precipitated by nanophthalmos. The ocular hypertension was responsive to topical medicines. Genetic analysis of known nanophthalmos genes MFRP and TMEM98 were negative, while a novel mutation, Thr518Met was detected in MYRF. The Thr518Met mutation was absent from 362 matched normal controls and was extremely rare in a large population database, allele frequency of 0.000024. The Thr518Met mutation altered a highly conserved amino acid in the MYRF protein and three of four algorithms suggested that this mutation is likely pathogenic. Finally, molecular modeling showed that the Thr518Met mutation is damaging to MYRF structure. Together these data suggest that the Thr518Met mutation causes nanophthalmos. Conclusions Nanophthalmos may present at an early age with features of angle closure glaucoma and a Thr518Met mutation in MYRF was detected in a patient with nanophthalmos. Prevalence data, homology data, mutation analysis data, and protein modeling data suggest that this variant is pathogenic and may expand the phenotypic range of syndromic nanophthalmos caused by MYRF mutations to include central nervous system abnormalities (increased posterior fossa cerebrospinal fluid).

PURPOSE: To characterize features of glaucoma associated with a TANK binding kinase 1 (TBK1) gene duplication, which is among the most common molecularly defined causes of normal tension glaucoma (NTG). DESIGN: Retrospective observational case series METHODS: We conducted a retrospective case series, by reviewing medical records of 7 members of a pedigree with normal tension glaucoma (NTG) caused by TBK1 gene duplications. Clinical features of these patients at diagnosis, throughout management, and at latest follow up were identified including age, intraocular pressure (IOP), central corneal thickness (CCT), optic nerve head appearance, and mean deviation (MD) assessed with Humphrey visual field (HVF) testing protocols. RESULTS: At initial diagnosis, the mean age was 35 ± 7 years, IOP was 16 ± 2.1 mm Hg, cup-to-disc (C/D) ratio was 0.9 ± 0.08, and MD assessed via HVF 30-2 and/or 24-2 testing protocols was −9.0 ± 8.9 (range: −1.8 to −27) dB in the 14 study eyes. At initial diagnosis, 4 (28%) of 14 eyes had no visual field defect, 4 (28%) had early visual field defects, and 6 (43%) had severe visual field defects. Patients had a mean follow-up of 21.5 ± 9.0 years and experienced an average reduction of IOP by 28%. Four of 12 eyes (33%) had stable visual fields throughout follow-up, while 8 eyes (67%) had slow to moderate progression. The 30-2 and/or 24-2 HVF tests had an average change in MD of −0.53 ± 0.26 dB/year. No eyes had rapid progression with a MD > 1.0 dB/year. At final follow up, the mean IOP was 11.5 ± 2.9, and C/D ratio was 0.94 ± 0.4. At final follow up, 3 (21%) of 14 eyes had early visual field defects, 4 (29%) of 14 eyes had moderate visual field defects, and 7 (50%) had severe visual field defects. Six (43%) of 14 eyes met criteria for legal blindness. CONCLUSIONS: We provide the first report of the clinical features and long-term clinical course in a family of NTG patients with TBK1 gene duplications. TBK1-associated glaucoma exhibits classic features of NTG. Patients present with severe disease at a relatively early age and most (67%) have slow to moderate progression of their visual field fields. The rate of visual field change appears correlated with the magnitude of IOP, suggesting that it may be advantageous to set extremely low IOP targets for some patients with TBK1-associated glaucoma.

Glaucoma is a complex disease caused by the combined effects of many genetic and environmental risk factors. Approximately 5% of glaucoma has a strong genetic basis, whereby a mutation in a single gene is responsible for disease. Many of these rare, single-gene forms of glaucoma frequently have an early age of onset and severe disease progression. Genetic research over the last few decades has led to the identification of three genes, myocilin, optineurin, and TBK1, that can cause glaucoma with little influence from other genes or the environment. Study of these genes has provided important insights into glaucoma pathogenesis and led to the discovery of specific biological pathways that are altered by disease. Furthermore, the study of disease-causing mutations lays the foundation for developing clinical genetic testing and mutation-directed therapies to improve clinical outcomes.

OBJECTIVE: Mutations in myocilin (MYOC) may cause either juvenile open angle glaucoma (JOAG) or adult-onset primary open angle glaucoma (POAG). MYOC encodes a glycoprotein that is normally secreted from trabecular meshwork cells that regulate intraocular pressure. Prior in vitro, transgenic rodent, and organ culture experiments have suggested that abnormal accumulation of MYOC protein within trabecular meshwork cells is a key step in glaucoma pathophysiology. We investigated the pathogenesis of MYOC glaucoma by examining a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation. DESIGN: Case-control, immunohistochemical study of a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation and age-matched control donor eyes. SUBJECTS: An eye from a 59-year-old male with JOAG caused by a Tyr437His MYOC mutation and eyes from five donors (ages 51–66) with no known ocular disease were examined. METHODS: Frozen fixed sections of the iridocorneal angle were prepared from the donor eyes of the MYOC glaucoma patient and control eyes. We used antibodies directed against MYOC, collagen IV, and BiP/GRP78 as well as wheat germ agglutinin and concanavalin A lectins to localize MYOC protein in the trabecular meshwork. MAIN OUTCOME MEASURE: Qualitative comparison of MYOC protein labeling and localization in the trabecular meshwork of donor eyes from a glaucoma patient with a MYOC mutation and from control subjects. RESULTS: Using immunohistochemistry, we detected more abundant MYOC protein within the trabecular meshwork of the MYOC glaucoma patient’s eye than in control eyes. We further localized MYOC protein within the trabecular meshwork cells of the MYOC glaucoma patient’s eye by co-labeling with the endoplasmic reticulum (ER) marker GRP78 (BiP). Little to no MYOC was identified within the trabecular meshwork cells of control eyes. Minimal extracellular MYOC was detected in both MYOC glaucoma eyes and control eyes. CONCLUSIONS: This is the first histopathological analysis of an eye from a glaucoma patient with a MYOC mutation. Furthermore, this analysis supports our model of MYOC-associated glaucoma, in which MYOC mutations cause abnormal intracellular retention of MYOC within the ER of trabecular meshwork cells as a key step towards development of glaucoma.

Gene correction is a valuable strategy for treating inherited retinal degenerative diseases, a major cause of irreversible blindness worldwide. Single gene defects cause the majority of these retinal dystrophies. Gene augmentation holds great promise if delivered early in the course of the disease, however, many patients carry mutations in genes too large to be packaged into adeno-associated viral vectors and some, when overexpressed via heterologous promoters, induce retinal toxicity. In addition to the aforementioned challenges, some patients have sustained significant photoreceptor cell loss at the time of diagnosis, rendering gene replacement therapy insufficient to treat the disease. These patients will require cell replacement to restore useful vision. Fortunately, the advent of induced pluripotent stem cell and CRISPR-Cas9 gene editing technologies affords researchers and clinicians a powerful means by which to develop strategies to treat patients with inherited retinal dystrophies. In this review we will discuss the current developments in CRISPR-Cas9 gene editing in vivo in animal models and in vitro in patient-derived cells to study and treat inherited retinal degenerative diseases.

Down syndrome is a genetic disease caused by trisomy of chromosome 21 that is characterized by numerous systemic abnormalities including intellectual disability, stereotypical facies, and congenital heart malformations. Ocular abnormalities are commonly seen with Down syndrome including corneal disease (keratoconus), refractive error, and atypical irides (Brushfield spots). We report the first case of aqueous misdirection in a patient with Down syndrome after trabeculectomy. Patients with Down syndrome often have small, hyperopic eyes with narrow iridocorneal angles and may be at increased risk for aqueous misdirection associated with surgical procedures. Awareness of this risk may aid surgical planning and post-operative management.

BACKGROUND Approximately 1% of normal tension glaucoma (NTG) cases are caused by TANK-binding kinase 1 (TBK1) gene duplications and triplications. However, the precise borders and orientation of these TBK1 gene copy number variations (CNVs) on chromosome 12 are unknown. METHODS We determined the exact borders of TBK1 CNVs and the orientation of duplicated or triplicated DNA segments in 5 NTG patients with different TBK1 mutations using whole-genome sequencing. RESULTS Tandemly duplicated chromosome segments spanning the TBK1 gene were detected in 4 NTG patients, each with unique borders. Four of 5 CNVs had borders located within interspersed repetitive DNA sequences (Alu and long interspersed nuclear element-L1 elements), suggesting that mismatched homologous recombinations likely generated these CNVs. A fifth NTG patient had a complex rearrangement including triplication of a chromosome segment spanning the TBK1 gene. CONCLUSIONS No specific mutation hotspots for TBK1 CNVs were detected, however, interspersed repetitive sequences (ie, Alu elements) were identified at the borders of TBK1 CNVs, which suggest that mismatch of these elements during meiosis may be the mechanism that generated TBK1 gene dosage mutations.

International audience; Exfoliation syndrome (XFS) is the commonest known risk factor for secondary glaucoma and a significant cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A have been previously associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results between populations,and to identify new variants associated with XFS. We identified a rare, protective allele at LOXL1 (p.407Phe, OR= 25, P=2.9 x 10-14) through deep resequencing of XFS cases and controls from 9 countries. This variant results in increased cellular adhesion strength compared to the wild-type (p.407Tyr) allele. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 x 10-8). Index variants at the new loci map to chromosomes 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS, and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.

Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.

The structure of the cornea is vital to its transparency, and dystrophies that disrupt corneal organization are highly heritable. To understand the genetic aetiology of Fuchs endothelial corneal dystrophy (FECD), the most prevalent corneal disorder requiring transplantation, we conducted a genome-wide association study (GWAS) on 1,404 FECD cases and 2,564 controls of European ancestry, followed by replication and meta-analysis, for a total of 2,075 cases and 3,342 controls. We identify three novel loci meeting genome-wide significance (P, Fuchs endothelial corneal dystrophy (FECD) is one of the most common reasons for corneal transplantation, and is known to cluster in families. Here, the authors discover new genetic loci associated with FECD with sex-specific effects and implications for disease mechanism.

Purpose of review In recent decades, investigators have identified numerous genes and genetic factors that cause or contribute risk for glaucoma. These findings have increased our understanding of disease mechanisms, provided us with new diagnostic tools, and may allow for development of improved therapies for glaucoma. However, genetic testing is most useful when it is reserved for appropriate patients. The purpose of this article is to review key points and recent developments regarding the genetics and genetic testing for glaucoma and to provide recommendations for when genetic testing may be warranted. Recent findings Large genome-wide association studies have identified multiple new susceptibility loci associated with primary open angle glaucoma and primary angle closure glaucoma. Summary Several glaucoma-causing genes and genetic risk factors for glaucoma have been discovered. As a result, there are specific clinical scenarios in which genetic testing is warranted. In select cases (i.e., familial juvenile open angle glaucoma), genetic testing can serve as a powerful tool to improve diagnostic accuracy, efficiency of disease surveillance, and selection of treatment, enabling physicians to better optimize care for their patients.

Item does not contain fulltext Primary open-angle glaucoma (POAG) is the most common chronic optic neuropathy worldwide. Epidemiological studies show a robust positive relation between intraocular pressure (IOP) and POAG and modest positive association between IOP and blood pressure (BP), while the relation between BP and POAG is controversial. The International Glaucoma Genetics Consortium (n=27 558), the International Consortium on Blood Pressure (n=69 395), and the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (n=37 333), represent genome-wide data sets for IOP, BP traits and POAG, respectively. We formed genome-wide significant variant panels for IOP and diastolic BP and found a strong relation with POAG (odds ratio and 95% confidence interval: 1.18 (1.14-1.21), P=1.8 x 10(-27)) for the former trait but no association for the latter (P=0.93). Next, we used linkage disequilibrium (LD) score regression, to provide genome-wide estimates of correlation between traits without the need for additional phenotyping. We also compared our genome-wide estimate of heritability between IOP and BP to an estimate based solely on direct measures of these traits in the Erasmus Rucphen Family (ERF; n=2519) study using Sequential Oligogenic Linkage Analysis Routines (SOLAR). LD score regression revealed high genetic correlation between IOP and POAG (48.5%, P=2.1 x 10(-5)); however, genetic correlation between IOP and diastolic BP (P=0.86) and between diastolic BP and POAG (P=0.42) were negligible. Using SOLAR in the ERF study, we confirmed the minimal heritability between IOP and diastolic BP (P=0.63). Overall, IOP shares genetic basis with POAG, whereas BP has limited shared genetic correlation with IOP or POAG.

A novel mutation (LEU396ARG) in OPA1 is associated with a severe phenotype in a large dominant optic atrophy pedigree

Purpose A genetic correlation is the proportion of phenotypic variance between traits that is shared on a genetic basis. Here we explore genetic correlations between diabetes- and glaucoma-related traits. Design Cross-sectional study. Methods We assembled genome-wide association study summary statistics from European-derived participants regarding diabetes-related traits like fasting blood sugar (FBS) and type 2 diabetes (T2D) and glaucoma-related traits (intraocular pressure [IOP], central corneal thickness [CCT], corneal hysteresis [CH], corneal resistance factor [CRF], cup-to-disc ratio [CDR], and primary open-angle glaucoma [POAG]). We included data from the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database, the UK Biobank, and the International Glaucoma Genetics Consortium. We calculated genetic correlation (rg) between traits using linkage disequilibrium score regression. We also calculated genetic correlations between IOP, CCT, and select diabetes-related traits based on individual level phenotype data in 2 Northern European population-based samples using pedigree information and Sequential Oligogenic Linkage Analysis Routines. Results Overall, there was little rg between diabetes- and glaucoma-related traits. Specifically, we found a nonsignificant negative correlation between T2D and POAG (rg = −0.14; P = .16). Using Sequential Oligogenic Linkage Analysis Routines, the genetic correlations between measured IOP, CCT, FBS, fasting insulin, and hemoglobin A1c were null. In contrast, genetic correlations between IOP and POAG (rg ≥ 0.45; P ≤ 3.0 × 10−4) and between CDR and POAG were high (rg = 0.57; P = 2.8 × 10−10). However, genetic correlations between corneal properties (CCT, CRF, and CH) and POAG were low (rg range −0.18 to 0.11) and nonsignificant (P ≥ .07). Conclusion These analyses suggest that there is limited genetic correlation between diabetes- and glaucoma-related traits.

Background We performed clinical and genetic characterization of a family with cavitary optic disc anomaly (CODA), an autosomal dominant condition that causes vision loss due to adult-onset maculopathy in the majority of cases. CODA is characterized by a variably excavated optic nerve appearance such as morning glory, optic pit, atypical coloboma, and severe optic nerve cupping. Methods Four affected and fourteen unaffected family members of a multi-generation pedigree were phenotyped by visual acuity, intraocular pressure, dilated fundus examination, fundus photography, and optical coherence tomography. Genetic analysis was performed by breakpoint polymerase chain reaction (PCR), long range PCR, and direct Sanger sequencing. The functional relevance of the copy number alteration region was assessed by in silico analysis. Results We found progressive optic nerve cupping in three affected members of a family with CODA. In one individual, an optic pit developed over time from a normal optic nerve. By two independent methods, we detected a previously described intergenic triplication that segregated with disease in all adults of the family. The copy number alteration was also detected in five children with normal optic nerves. eQTL analysis demonstrated that this CNA region regulates expression of up to 4 genes in cis. Conclusions Morning glory, optic pit and atypical coloboma are currently considered congenital anomalies of the optic nerve, but our data indicate that in CODA, the excavated optic nerve appearance may develop after birth and into adulthood. In silico analysis of the CNA, may explain why vairable expressivity is observed in CODA. Electronic supplementary material The online version of this article (10.1186/s12881-019-0800-4) contains supplementary material, which is available to authorized users.

Purpose To evaluate the first association specific to exudative age-related macular degeneration (AMD) located near the matrix metalloproteinase 9 (MMP9) gene. Design Genetic association study. Participants One thousand seven hundred twelve patients with AMD (672 nonexudative, 1040 exudative) of predominantly northern European descent seeking treatment at the University of Iowa Hospitals and Clinics. Methods We reanalyzed the International AMD Genetics Consortium (IAMDGC) data to validate the association of polymorphisms near MMP9 with exudative AMD and to identify additional associated single nucleotide polymorphisms (SNPs), especially MMP9 coding sequence SNPs. We genotyped a cohort of 1712 AMD patients from Iowa with 3 SNPs identified with our analysis of the IAMDGC cohort using commercially available real-time quantitative polymerase chain reaction (PCR) assays. Firth regression was used to measure the association between MMP9 SNP genotypes and exudative AMD in our cohort of patients from Iowa. In addition, we developed a PCR-based assay to genotype the Iowa cohort at a short tandem repeat polymorphism (STRP) at the MMP9 locus. Main Outcome Measures Odds ratios and P values for exudative compared with nonexudative AMD patients in the Iowa cohort for MMP9 SNPs (rs4810482, rs17576, and rs17577) and STRP. Results We identified 3 SNPs in the MMP9 locus (rs4810482, rs17576, and rs17577) that are highly associated with exudative AMD in patient cohorts of the IAMDGC. These MMP9 SNPs also are associated with exudative AMD in the cohort of 1712 AMD patients from Iowa (rs4810482: odds ratio [OR], 0.82; P = 0.010; rs17576: OR, 0.86; P = 0.046; and rs17577: OR, 0.80; P = 0.041). We also genotyped the cohort of AMD patients from Iowa at rs142450006, another MMP9 polymorphism that previously was associated with exudative AMD. We detected a 4bp STRP, (TTTC)n, at the rs142450006 locus that is highly polymorphic and associated significantly with exudative AMD (OR, 0.78; P = 0.016). Conclusions This study independently confirms and expands an association between the MMP9 locus and exudative AMD, further implicating a role for extracellular matrix abnormalities in choroidal neovascularization.

Purpose Primary open-angle glaucoma (POAG) is a major cause of blindness and visual disability. Several genetic risk factors for POAG and optic nerve features have been identified. We measured the relative risk for glaucoma that these factors contribute to participants in the Ocular Hypertension Treatment Study (OHTS). Design Comparative series. Participants One thousand fifty-seven of 1636 participants (65%) of the OHTS were enrolled in this genetics ancillary study. Methods Samples of DNA were available from 1057 OHTS participants. Of these, 209 developed POAG (cases) and 848 did not develop glaucoma (controls) between 1994 and 2009. The frequencies of 13 risk alleles previously associated with POAG or with optic disc features in other cohorts were compared between POAG cases and controls in the OHTS cohort using analyses of variance. The 2 largest subgroups, non-Hispanic whites (n = 752; 70.7%) and blacks (n = 249, 23.7%), also were analyzed separately. The probability of glaucoma developing over the course of the OHTS was compared between participants stratified for transmembrane and coiled-coil domains 1 ( TMCO1 ) risk alleles using Kaplan-Meier and Cox proportional hazards analyses. Main Outcome Measures Association of POAG with known genetic factors. Results No association was detected between the known POAG risk alleles when the OHTS cohort was examined as a whole. However, in the subgroup of non-Hispanic whites, allele frequencies at the TMCO1 locus were statistically different between cases and controls ( P = 0.00028). By 13 years, non-Hispanic white participants with TMCO1 risk alleles had a 12% higher cumulative frequency of glaucoma developing than participants with no TMCO1 risk alleles. Moreover, the Cox proportional hazard analysis demonstrated that TMCO1 alleles increased relative risk comparable with that of some previously analyzed clinical measures (i.e., intraocular pressure). Conclusions The size of the OHTS cohort and its composition of 2 large racial subgroups may limit its power to detect some glaucoma risk factors. However, TMCO1 genotype was found to increase the risk of glaucoma developing among non-Hispanic whites, the largest racial subgroup in the OHTS cohort, at a magnitude similar to clinical predictors of disease that long have been associated with glaucoma.

To both characterize the clinical features of large primary open angle glaucoma (POAG) pedigree from a village in southern India and to investigate the genetic basis of their disease.Eighty-four members of a large pedigree received complete eye examinations including slit lamp examination, tonometry, gonioscopy, and ophthalmoscopy. Some were further studied with perimetry. Those diagnosed with POAG were tested for disease-causing mutations in the myocilin and optineurin genes with Sanger sequencing.Fourteen of 84 family members were diagnosed with POAG, while eight were clinically judged to be POAG-suspects. The family structure and the pattern of glaucoma in the pedigree are complex. Features of glaucoma in this pedigree include relatively early age at diagnosis (mean 50 ± 14 years) and maximum intraocular pressures ranging from 14 to 36 mm Hg with a mean of 23 mm Hg ± 6.5 mm Hg. Patients had an average central corneal thickness (mean 529 ± 37.8 microns) and moderate cup-to-disc ratios (0.74 ± 0.14). No mutations were detected in myocilin, optineurin, or TANK binding kinase 1 (TBK1).We report a five-generation pedigree with a complex pattern of POAG inheritance that includes 22 POAG patients and glaucoma suspects. Although the familial clustering of POAG in this pedigree is consistent with dominant inheritance of a glaucoma-causing gene, mutations were not detected in genes previously associated with autosomal dominant glaucoma, suggesting the involvement of a novel disease-causing gene in this pedigree.

PurposeTo identify specific mutations causing North Carolina macular dystrophy (NCMD).DesignWhole-genome sequencing coupled with reverse transcription polymerase chain reaction (RT-PCR) analysis of gene expression in human retinal cells.ParticipantsA total of 141 members of 12 families with NCMD and 261 unrelated control individuals.MethodsGenome sequencing was performed on 8 affected individuals from 3 families affected with chromosome 6–linked NCMD (MCDR1) and 2 individuals affected with chromosome 5–linked NCMD (MCDR3). Variants observed in the MCDR1 locus with frequencies

© 2016, Association for Research in Vision and Ophthalmology Inc. All rights reserved. PURPOSE. Recent studies indicate that mitochondrial proteins may contribute to the pathogenesis of primary open-angle glaucoma (POAG). In this study, we examined the association between POAG and common variations in gene-encoding mitochondrial proteins. METHODS. We examined genetic data from 3430 POAG cases and 3108 controls derived from the combination of the GLAUGEN and NEIGHBOR studies. We constructed biological-system coherent mitochondrial nuclear-encoded protein gene-sets by intersecting the MitoCarta database with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We examined the mitochondrial gene-sets for association with POAG and with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) subsets using Pathway Analysis by Randomization Incorporating Structure. RESULTS. We identified 22 KEGG pathways with significant mitochondrial protein-encoding gene enrichment, belonging to six general biological classes. Among the pathway classes, mitochondrial lipid metabolism was associated with POAG overall (P = 0.013) and with NTG (P = 0.0006), and mitochondrial carbohydrate metabolism was associated with NTG (P = 0.030). Examining the individual KEGG pathway mitochondrial gene-sets, fatty acid elongation and synthesis and degradation of ketone bodies, both lipid metabolism pathways, were significantly associated with POAG (P = 0.005 and P = 0.002, respectively) and NTG (P = 0.0004 and P < 0.0001, respectively). Butanoate metabolism, a carbohydrate metabolism pathway, was significantly associated with POAG (P = 0.004), NTG (P = 0.001), and HTG (P = 0.010). CONCLUSIONS. We present an effective approach for assessing the contributions of mitochondrial genetic variation to open-angle glaucoma. Our findings support a role for mitochondria in POAG pathogenesis and specifically point to lipid and carbohydrate metabolism pathways as being important.