Centre for Eye Research Australia (CERA) - 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 genetic and clinical landscape of nanophthalmos and posterior microphthalmos in an Australian cohort
    Siggs, OM ; Awadalla, MS ; Souzeau, E ; Staffieri, SE ; Kearns, LS ; Laurie, K ; Kuot, A ; Qassim, A ; Edwards, TL ; Coote, MA ; Mancel, E ; Walland, MJ ; Dondey, J ; Galanopoulous, A ; Casson, RJ ; Mills, RA ; MacArthur, DG ; Ruddle, JB ; Burdon, KP ; Craig, JE (WILEY, 2020-05)
    Nanophthalmos and posterior microphthalmos are ocular abnormalities in which both eyes are abnormally small, and typically associated with extreme hyperopia. We recruited 40 individuals from 13 kindreds with nanophthalmos or posterior microphthalmos, with 12 probands subjected to exome sequencing. Nine probands (69.2%) were assigned a genetic diagnosis, with variants in MYRF, TMEM98, MFRP, and PRSS56. Two of four PRSS56 families harbored the previously described c.1066dupC variant implicated in over half of all reported PRSS56 kindreds, with different surrounding haplotypes in each family suggesting a mutational hotspot. Individuals with a genetic diagnosis had shorter mean axial lengths and higher hyperopia than those without, with recessive forms associated with the most extreme phenotypes. These findings detail the genetic architecture of nanophthalmos and posterior microphthalmos in a cohort of predominantly European ancestry, their relative clinical phenotypes, and highlight the shared genetic architecture of rare and common disorders of refractive error.
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    Multitrait analysis of glaucoma identifies new risk loci and enables polygenic prediction of disease susceptibility and progression
    Craig, JE ; Han, X ; Qassim, A ; Hassall, M ; Bailey, JNC ; Kinzy, TG ; Khawaja, AP ; An, J ; Marshall, H ; Gharahkhani, P ; Igo, RP ; Graham, SL ; Healey, PR ; Ong, J-S ; Zhou, T ; Siggs, O ; Law, MH ; Souzeau, E ; Ridge, B ; Hysi, PG ; Burdon, KP ; Mills, RA ; Landers, J ; Ruddle, JB ; Agar, A ; Galanopoulos, A ; White, AJR ; Willoughby, CE ; Andrew, NH ; Best, S ; Vincent, AL ; Goldberg, I ; Radford-Smith, G ; Martin, NG ; Montgomery, GW ; Vitart, V ; Hoehn, R ; Wojciechowski, R ; Jonas, JB ; Aung, T ; Pasquale, LR ; Cree, AJ ; Sivaprasad, S ; Vallabh, NA ; Viswanathan, AC ; Pasutto, F ; Haines, JL ; Klaver, CCW ; van Duijn, CM ; Casson, RJ ; Foster, PJ ; Khaw, PT ; Hammond, CJ ; Mackey, DA ; Mitchell, P ; Lotery, AJ ; Wiggs, JL ; Hewitt, AW ; MacGregor, S (NATURE PORTFOLIO, 2020-02)
    Glaucoma, a disease characterized by progressive optic nerve degeneration, can be prevented through timely diagnosis and treatment. We characterize optic nerve photographs of 67,040 UK Biobank participants and use a multitrait genetic model to identify risk loci for glaucoma. A glaucoma polygenic risk score (PRS) enables effective risk stratification in unselected glaucoma cases and modifies penetrance of the MYOC variant encoding p.Gln368Ter, the most common glaucoma-associated myocilin variant. In the unselected glaucoma population, individuals in the top PRS decile reach an absolute risk for glaucoma 10 years earlier than the bottom decile and are at 15-fold increased risk of developing advanced glaucoma (top 10% versus remaining 90%, odds ratio = 4.20). The PRS predicts glaucoma progression in prospectively monitored, early manifest glaucoma cases (P = 0.004) and surgical intervention in advanced disease (P = 3.6 × 10-6). This glaucoma PRS will facilitate the development of a personalized approach for earlier treatment of high-risk individuals, with less intensive monitoring and treatment being possible for lower-risk groups.
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    Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error
    Fan, Q ; Pozarickij, A ; Tan, NYQ ; Guo, X ; Verhoeven, VJM ; Vitart, V ; Guggenheim, JA ; Miyake, M ; Tideman, JWL ; Khawaja, AP ; Zhang, L ; MacGregor, S ; Hoehn, R ; Chen, P ; Biino, G ; Wedenoja, J ; Saffari, SE ; Tedja, MS ; Xie, J ; Lanca, C ; Wang, YX ; Sahebjada, S ; Mazur, J ; Mirshahi, A ; Martin, NG ; Yazar, S ; Pennell, CE ; Yap, M ; Haarman, AEG ; Enthoven, CA ; Polling, J ; Hewitt, AW ; Jaddoe, VWV ; van Duijn, CM ; Hayward, C ; Polasek, O ; Tai, E-S ; Yoshikatsu, H ; Hysi, PG ; Young, TL ; Tsujikawa, A ; Wang, JJ ; Mitchell, P ; Pfeiffer, N ; Parssinen, O ; Foster, PJ ; Fossarello, M ; Yip, SP ; Williams, C ; Hammond, CJ ; Jonas, JB ; He, M ; Mackey, DA ; Wong, T-Y ; Klaver, CCW ; Saw, S-M ; Baird, PN ; Cheng, C-Y (NATURE PORTFOLIO, 2020-03-19)
    Corneal curvature, a highly heritable trait, is a key clinical endophenotype for myopia - a major cause of visual impairment and blindness in the world. Here we present a trans-ethnic meta-analysis of corneal curvature GWAS in 44,042 individuals of Caucasian and Asian with replication in 88,218 UK Biobank data. We identified 47 loci (of which 26 are novel), with population-specific signals as well as shared signals across ethnicities. Some identified variants showed precise scaling in corneal curvature and eye elongation (i.e. axial length) to maintain eyes in emmetropia (i.e. HDAC11/FBLN2 rs2630445, RBP3 rs11204213); others exhibited association with myopia with little pleiotropic effects on eye elongation. Implicated genes are involved in extracellular matrix organization, developmental process for body and eye, connective tissue cartilage and glycosylation protein activities. Our study provides insights into population-specific novel genes for corneal curvature, and their pleiotropic effect in regulating eye size or conferring susceptibility to myopia.