Ophthalmology (Eye & Ear Hospital) - Research Publications

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    Diagnostic yield of candidate genes in an Australian corneal dystrophy cohort
    Souzeau, E ; Siggs, OM ; Mullany, S ; Schmidt, JM ; Hassall, MM ; Dubowsky, A ; Chappell, A ; Breen, J ; Bae, H ; Nicholl, J ; Hadler, J ; Kearns, LS ; Staffieri, SE ; Hewitt, AW ; Mackey, DA ; Gupta, A ; Burdon, KP ; Klebe, S ; Craig, JE ; Mills, RA (WILEY, 2022-10)
    Corneal dystrophies describe a clinically and genetically heterogeneous group of inherited disorders. The International Classification of Corneal Dystrophies (IC3D) lists 22 types of corneal dystrophy, 17 of which have been demonstrated to result from pathogenic variants in 19 identified genes. In this study, we investigated the diagnostic yield of genetic testing in a well-characterised cohort of 58 individuals from 44 families with different types of corneal dystrophy. Individuals diagnosed solely with Fuchs endothelial corneal dystrophy were excluded. Clinical details were obtained from the treating ophthalmologist. Participants and their family members were tested using a gene candidate and exome sequencing approach. We identified a likely molecular diagnosis in 70.5% families (31/44). The detection rate was significantly higher among probands with a family history of corneal dystrophy (15/16, 93.8%) than those without (16/28, 57.1%, p = .015), and among those who had undergone corneal graft surgery (9/9, 100.0%) compared to those who had not (22/35, 62.9%, p = .041). We identified eight novel variants in five genes and identified five families with syndromes associated with corneal dystrophies. Our findings highlight the genetic heterogeneity of corneal dystrophies and the clinical utility of genetic testing in reaching an accurate clinical diagnosis.
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    Attitudes Toward Glaucoma Genetic Risk Assessment in Unaffected Individuals
    Hollitt, GL ; Siggs, OM ; Ridge, B ; Keane, MC ; Mackey, DA ; MacGregor, S ; Hewitt, AW ; Craig, JE ; Souzeau, E (ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 2022-10)
    PURPOSE: Integrating polygenic risk scores (PRS) into healthcare has the potential to stratify an individual's risk of glaucoma across a broad population. Glaucoma is the most common cause of irreversible blindness worldwide, therefore effective screening for glaucoma endorsed by the population is highly important. This study assessed the attitude of unaffected individuals toward PRS testing for glaucoma, and sought to identify factors associated with interest in testing. METHODS: We surveyed 418 unaffected individuals including 193 with a first-degree relative with glaucoma, 117 who had a recent eye examination, and 108 general members of the community. RESULTS: Overall, 71.3% of the individuals indicated an interest in taking a polygenic risk test for glaucoma. Interest was more likely in those who believed glaucoma to be a severe medical condition (odds ratio [OR] = 14.58, 95% confidence interval [CI] = 1.15-185.50, P = 0.039), those concerned about developing glaucoma (OR = 4.37, 95% CI = 2.32-8.25, P < 0.001), those with an intention to take appropriate measures regarding eye health (OR = 2.39, 95% CI = 1.16-4.95, P = 0.019), and those preferring to know if considered to be at-risk or not (OR = 4.52, 95% CI = 2.32-8.83, P < 0.001). CONCLUSIONS: Our results show strong interest in genetic risk assessment for glaucoma among unaffected individuals in Australia. TRANSLATIONAL RELEVANCE: These findings represent a valuable assessment of interest in glaucoma polygenic risk testing among potential target populations, which will be integral to the implementation and uptake of novel PRS-based tests into clinical practice.
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    Retinal ganglion cell-specific genetic regulation in primary open-angle glaucoma
    Daniszewski, M ; Senabouth, A ; Liang, HH ; Han, X ; Lidgerwood, GE ; Hernandez, D ; Sivakumaran, P ; Clarke, JE ; Lim, SY ; Lees, JG ; Rooney, L ; Gulluyan, L ; Souzeau, E ; Graham, SL ; Chan, C-L ; Nguyen, U ; Farbehi, N ; Gnanasambandapillai, V ; Mccloy, RA ; Clarke, L ; Kearns, LS ; Mackey, DA ; Craig, JE ; Macgregor, S ; Powell, JE ; Pebay, A ; Hewitt, AW (ELSEVIER, 2022-06-08)
    To assess the transcriptomic profile of disease-specific cell populations, fibroblasts from patients with primary open-angle glaucoma (POAG) were reprogrammed into induced pluripotent stem cells (iPSCs) before being differentiated into retinal organoids and compared with those from healthy individuals. We performed single-cell RNA sequencing of a total of 247,520 cells and identified cluster-specific molecular signatures. Comparing the gene expression profile between cases and controls, we identified novel genetic associations for this blinding disease. Expression quantitative trait mapping identified a total of 4,443 significant loci across all cell types, 312 of which are specific to the retinal ganglion cell subpopulations, which ultimately degenerate in POAG. Transcriptome-wide association analysis identified genes at loci previously associated with POAG, and analysis, conditional on disease status, implicated 97 statistically significant retinal ganglion cell-specific expression quantitative trait loci. This work highlights the power of large-scale iPSC studies to uncover context-specific profiles for a genetically complex disease.
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    The APOE E4 Allele Is Associated with Faster Rates of Neuroretinal Thinning in a Prospective Cohort Study of Suspect and Early Glaucoma
    Mullany, S ; Marshall, H ; Diaz-Torres, S ; Berry, EC ; Schmidt, JM ; Thomson, D ; Qassim, A ; To, M-S ; Dimasi, D ; Kuot, A ; Knight, LSW ; Hollitt, G ; Kolovos, A ; Schulz, A ; Lake, S ; Mills, RA ; Agar, A ; Galanopoulos, A ; Landers, J ; Mitchell, P ; Healey, PR ; Graham, SL ; Hewitt, AW ; Souzeau, E ; Hassall, MM ; Klebe, S ; MacGregor, S ; Gharahkhani, P ; Casson, RJ ; Siggs, OM ; Craig, JE (Elsevier, 2022-06)
    Purpose: To investigate the association between the apolipoprotein E (APOE) E4 dementia-risk allele and prospective longitudinal retinal thinning in a cohort study of suspect and early manifest glaucoma. Design: Retrospective analysis of prospective cohort data. Participants: This study included all available eyes from participants recruited to the Progression Risk of Glaucoma: Relevant SNPs [single nucleotide polymorphisms] with Significant Association (PROGRESSA) study with genotyping data from which APOE genotypes could be determined. Methods: Apolipoprotein E alleles and genotypes were determined in PROGRESSA, and their distributions were compared with an age-matched and ancestrally matched normative cohort, the Blue Mountains Eye Study. Structural parameters of neuroretinal atrophy measured using spectral-domain OCT were compared within the PROGRESSA cohort on the basis of APOE E4 allele status. Main Outcome Measures: Longitudinal rates of thinning in the macular ganglion cell–inner plexiform layer (mGCIPL) complex and the peripapillary retinal nerve fiber layer (pRNFL). Results: Rates of mGCIPL complex thinning were faster in participants harboring ≥1 copies of the APOE E4 allele (β = –0.13 μm/year; P ≤0.001). This finding was strongest in eyes affected by normal-tension glaucoma (NTG; β = –0.20 μm/year; P = 0.003). Apolipoprotein E E4 allele carriers were also more likely to be lost to follow-up (P = 0.01) and to demonstrate a thinner average mGCIPL complex (70.9 μm vs. 71.9 μm; P = 0.011) and pRNFL (77.6 μm vs. 79.2 μm; P = 0.045) after a minimum of 3 years of monitoring. Conclusions: The APOE E4 allele was associated with faster rates of mCGIPL complex thinning, particularly in eyes with NTG. These results suggest that the APOE E4 allele may be a risk factor for retinal ganglion cell degeneration in glaucoma.
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    The Relationship Between Fetal Growth and Retinal Nerve Fiber Layer Thickness in a Cohort of Young Adults
    Dyer, KIC ; Sanfilippo, PG ; Yazar, S ; Craig, JE ; Hewitt, AW ; Newnham, JP ; Mackey, DA ; Lee, SSY (ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 2022-07)
    PURPOSE: To explore relationships between patterns of fetal anthropometric growth, as reflective of fetal wellbeing, and global retinal nerve fiber layer (RNFL) thickness measured in young adulthood. METHODS: Participants (n = 481) from within a Western Australian pregnancy cohort study underwent five serial ultrasound scans during gestation, with fetal biometry measured at each scan. Optic disc parameters were measured via spectral-domain optical coherence tomography imaging at a 20-year follow-up eye examination. Generalized estimating equations were used to evaluate differences in global RNFL thickness between groups of participants who had undergone similar growth trajectories based on fetal head circumference (FHC), abdominal circumference (FAC), femur length (FFL), and estimated fetal weight (EFW). RESULTS: Participants with consistently large FHCs throughout gestation had significantly thicker global RNFLs than those with any other pattern of FHC growth (P = 0.023), even after adjustment for potential confounders (P = 0.037). Based on model fit statistics, FHC growth trajectory was a better predictor of global RNFL thickness than birth weight or head circumference at birth. RNFL thickness did not vary significantly between groups of participants with different growth trajectories based on FAC, FFL, or EFW. CONCLUSIONS: FHC growth is associated with RNFL thickness in young adulthood and, moreover, is a better predictor than either birth weight or head circumference at birth. TRANSLATIONAL RELEVANCE: This research demonstrates an association between intrauterine growth and long-term optic nerve health, providing a basis for further exploring the extent of the influence of fetal wellbeing on clinical conditions linked to RNFL thinning.
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    Attitudes Towards Polygenic Risk Testing in Individuals with Glaucoma
    Hollitt, GL ; Siggs, OM ; Ridge, B ; Keane, MC ; Mackey, DA ; MacGregor, S ; Hewitt, AW ; Craig, JE ; Souzeau, E (ELSEVIER, 2022-09)
    PURPOSE: Glaucoma is the leading cause of irreversible blindness worldwide; however, vision loss resulting from glaucoma generally can be prevented through early identification and timely implementation of treatment. Recently, polygenic risk scores (PRSs) have shown promise in stratifying individual risk and prognostication for primary open-angle glaucoma (POAG) to reduce disease burden. Integrating PRS testing into clinical practice is becoming increasingly realistic; however, little is known about the attitudes of patients toward such testing. DESIGN: Cross-sectional, questionnaire-based study. PARTICIPANTS: Among the participants in the Australian and New Zealand Registry of Advanced Glaucoma, 2369 were invited to participate who fit the inclusion criteria of adults with a diagnosis of POAG who had not received genetic results that explain their condition, were not known to be deceased, resided in Australia, and had agreed to receive correspondence. METHODS: One thousand one hundred sixty-nine individuals (response rate, 49%) with POAG completed the survey evaluating their attitudes towards polygenic risk testing for glaucoma. MAIN OUTCOME MEASURES: Sociodemographic, health, perception, and emotional factors were examined to assess associations with interest in PRS testing. Interest in PRS testing was evaluated through assessing likelihood to take the test to predict personal risk of disease and disease severity, and whether the individual would recommend the test to family members or others. RESULTS: Our results show strong interest in the test, with 69.4% of individuals (798 of 1150) indicating a keenness in testing before diagnosis, had it been available. In particular, interest was seen in those from an urban area (odds ratio [OR], 1.70; 95% confidence interval [CI], 1.15-2.49; P = 0.007), those who perceived their risk of developing glaucoma as higher (OR, 2.05; 95% CI, 1.28-3.29; P = 0.003), and those who were worried about developing glaucoma (OR, 2.07; 95% CI, 1.27-3.37; P = 0.004). People who were interested in testing were more likely to change their eye health-seeking intentions and to recommend testing to family members and others, as well as to undergo testing for prognostication. CONCLUSIONS: These findings will help to facilitate the clinical implementation of PRS testing for glaucoma to reduce irreversible vision loss.
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    Cardiovascular Disease Predicts Structural and Functional Progression in Early Glaucoma
    Marshall, H ; Mullany, S ; Qassim, A ; Siggs, O ; Hassall, M ; Ridge, B ; Thi, N ; Awadalla, M ; Andrew, NH ; Healey, PR ; Agar, A ; Galanopoulos, A ; Hewitt, AW ; MacGregor, S ; Graham, SL ; Mills, R ; Shulz, A ; Landers, J ; Casson, RJ ; Craig, JE (ELSEVIER SCIENCE INC, 2021-01)
    PURPOSE: To investigate the association between cardiovascular disease and baseline structural defects and disease progression in glaucoma. DESIGN: Prospective, longitudinal study of preperimetric and perimetric glaucoma. PARTICIPANTS: Two thousand six hundred twenty-eight eyes from 1314 participants recruited to the Progression Risk of Glaucoma: Relevant SNPs with Significant Association (PROGRESSA) study were evaluated for baseline and longitudinal structural thinning using spectral-domain OCT and for visual field progression on Humphrey visual field (HVF) assessment. METHODS: Patients were classified as either predominantly macula ganglion cell-inner plexiform layer (mGCIPL), predominantly peripapillary retinal nerve fiber layer (pRNFL), or both mGCIPL and pRNFL structural change at enrollment, and then evaluated for longitudinal OCT or HVF progression. Cardiovascular disease and medication characteristics of the participants were compared with a reference group of stable patients. MAIN OUTCOME MEASURES: OCT and HVF baseline status and longitudinal progression. RESULTS: After accounting for age and cardiovascular characteristics, patients with predominantly mGCIPL thinning at baseline showed a higher prevalence of hypertension (odds ratio [OR], 2.70; 95% confidence interval [CI], 1.66-4.41; P < 0.001), antihypertensive use (OR, 2.03; 95% CI, 1.20-3.46; P = 0.008), and statin use (OR, 1.98; 95% CI, 1.07-3.66; P = 0.029) than reference patients. Patients with predominantly pRNFL thinning exhibited a comparable prevalence of cardiovascular disease or medication with reference patients. Review of longitudinal OCT and HVF data (mean follow-up, 5.34 ± 1.29 years) showed that hypertension was associated with an increased risk of both OCT (OR, 1.79; 95% CI, 1.17-2.75; P = 0.006) and HVF progression (OR, 1.92; 95% CI, 1.18-3.15; P = 0.013). A 1-standard deviation (approximately 21 mmHg) increase in systolic blood pressure at baseline was associated with a greater risk of OCT progression (OR, 1.27; 95% CI, 1.01-1.63; P = 0.041) and HVF progression (OR, 1.32; 95% CI, 1.01-1.73; P = 0.043). The association between systolic blood pressure and structural progression was comparable to that observed between intraocular pressure and structural progression (OR, 1.30; 95% CI, 1.01-1.67; P = 0.039). CONCLUSIONS: Cardiovascular disease is an important risk factor for glaucoma progression.
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    Identifying Genetic Biomarkers Predicting Response to Anti-Vascular Endothelial Growth Factor Injections in Diabetic Macular Edema
    Gurung, RL ; FitzGerald, LM ; Liu, E ; McComish, BJ ; Kaidonis, G ; Ridge, B ; Hewitt, AW ; Vote, BJ ; Verma, N ; Craig, JE ; Burdon, KP (MDPI, 2022-04)
    Intraocular anti-vascular endothelial growth factor (VEGF) therapies are the front-line treatment for diabetic macular edema (DME); however, treatment response varies widely. This study aimed to identify genetic determinants associated with anti-VEGF treatment response in DME. We performed a genome-wide association study on 220 Australian patients with DME treated with anti-VEGF therapy, genotyped on the Illumina Global Screening Array, and imputed to the Haplotype Reference Consortium panel. The primary outcome measures were changes in central macular thickness (CMT in microns) and best-corrected visual acuity (BCVA in ETDRS letters) after 12 months. Association between single nucleotide polymorphism (SNP) genotypes and DME outcomes were evaluated by linear regression, adjusting for the first three principal components, age, baseline CMT/BCVA, duration of diabetic retinopathy, and HbA1c. Two loci reached genome-wide significance (p < 5 × 10−8) for association with increased CMT: a single SNP on chromosome 6 near CASC15 (rs78466540, p = 1.16 × 10−9) and a locus on chromosome 12 near RP11-116D17.1 (top SNP rs11614480, p = 2.69 × 10−8). Four loci were significantly associated with reduction in BCVA: two loci on chromosome 11, downstream of NTM (top SNP rs148980760, p = 5.30 × 10−9) and intronic in RP11-744N12.3 (top SNP rs57801753, p = 1.71 × 10−8); one near PGAM1P1 on chromosome 5 (rs187876551, p = 1.52 × 10−8); and one near TBC1D32 on chromosome 6 (rs118074968, p = 4.94 × 10−8). In silico investigations of each locus identified multiple expression quantitative trait loci and potentially relevant candidate genes warranting further analysis. Thus, we identified multiple genetic loci predicting treatment outcomes for anti-VEGF therapies in DME. This work may potentially lead to managing DME using personalized treatment approaches.
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    The effect of insulin on response to intravitreal anti-VEGF injection in diabetic macular edema in type 2 diabetes mellitus
    Gurung, RL ; FitzGerald, LM ; Liu, E ; McComish, BJ ; Kaidonis, G ; Ridge, B ; Hewitt, AW ; Vote, BJ ; Verma, N ; Craig, JE ; Burdon, KP (BMC, 2022-02-28)
    OBJECTIVES: To assess whether insulin therapy impacts the effectiveness of anti-vascular endothelial growth factor (anti-VEGF) injection for the treatment of diabetic macular edema (DME) in type 2 diabetes mellitus. METHODS: This was a retrospective multi-center analysis. The best-corrected visual acuity (BCVA) at 12 months, BCVA change, central macular thickness (CMT), CMT change, and cumulative injection number were compared between the insulin and the oral hypoglycemic agent (OHA) groups. RESULTS: The mean final BCVA and CMT improved in both the insulin (N = 137; p < 0.001; p < 0.001, respectively) and the OHA group (N = 61; p = 0.199; p < 0.001, respectively). The two treatment groups were comparable for final BCVA (p = 0.263), BCVA change (p = 0.184), final CMT (p = 0.741), CMT change (p = 0.458), and the cumulative injections received (p = 0.594). The results were comparable between the two groups when stratified by baseline vision (p > 0.05) and baseline HbA1c (p > 0.05). CONCLUSION: Insulin therapy does not alter treatment outcomes for anti-VEGF therapy in DME.
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    Rare variants in optic disc area gene CARD10 enriched in primary open-angle glaucoma
    Zhou, T ; Souzeau, E ; Sharma, S ; Siggs, OM ; Goldberg, I ; Healey, PR ; Graham, S ; Hewitt, AW ; Mackey, DA ; Casson, RJ ; Landers, J ; Mills, R ; Ellis, J ; Leo, P ; Brown, MA ; MacGregor, S ; Burdon, KP ; Craig, JE (WILEY, 2016-11)
    BACKGROUND: Genome-wide association studies (GWAS) have identified association of common alleles with primary open-angle glaucoma (POAG) and its quantitative endophenotypes near numerous genes. This study aims to determine whether rare pathogenic variants in these disease-associated genes contribute to POAG. METHODS: Participants fulfilled strict inclusion criteria of advanced POAG at a young age of diagnosis. Myocilin mutation carriers were excluded using direct sequencing. Whole exome sequencing was performed on 187 glaucoma cases and 103 local screened nonglaucoma controls then joint-called with exomes of 993 previously sequenced Australian controls. GWAS-associated genes were assessed for enrichment of rare predicted pathogenic variants in POAG. Significantly enriched genes were compared against Exome Aggregation Consortium (ExAC) public control. RESULTS: Eighty-six GWAS disease or trait-associated glaucoma genes were captured and sequenced. CARD10 showed enrichment after Bonferroni correction for rare variants in glaucoma cases (OR = 13.2, P = 6.94 × 10-5) with mutations identified in 4.28% of our POAG cohort compared to 0.27% in controls. CARD10 was significantly associated with optic disc parameters in previous GWAS. The whole GWAS gene set showed no enrichment in POAG overall (OR = 1.12, P = 0.51). CONCLUSION: We report here an enrichment of rare predicted pathogenic coding variants within a GWAS-associated locus in POAG (CARD10). These findings indicate that both common and rare pathogenic coding variants in CARD10 may contribute to POAG pathogenesis.