1
|
Aslaksen S, Aukrust I, Molday L, Holtan JP, Jansson RW, Berland S, Rødahl E, Bredrup C, Bragadóttir R, Bratland E, Molday RS, Knappskog PM. Functional Characterization of ABCA4 Missense Variants Aids Variant Interpretation and Phenotype Prediction in Patients With ABCA4-Retinal Dystrophies. Invest Ophthalmol Vis Sci 2024; 65:2. [PMID: 39087934 PMCID: PMC11305421 DOI: 10.1167/iovs.65.10.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 07/01/2024] [Indexed: 08/02/2024] Open
Abstract
Purpose Biallelic pathogenic variants in the gene encoding the ATP-binding cassette transporter ABCA4 are the leading cause of irreversible vision loss in inherited retinal dystrophies (IRDs). Interpretation of ABCA4 variants is challenging, due to cis-modifying and hypomorphic variants. We have previously detected 10 missense variants of unknown significance (VUS) in patients with suspected ABCA4-retinal dystrophies (ABCA4-RDs) in Norway. In this study, we functionally characterized the VUS to aid interpretation of the variants and to determine if they are associated with the disease. Methods The ABCA4 VUS were expressed in HEK293T cells and the ABCA4 expression level and ATPase activity were determined and correlated with the patients' phenotype. The functional data further used for reclassification of the VUS following the American College of Medical Genetics and Genomics (ACMG) guidelines. Results Of the 10 VUSs, 2 variants, Cys205Phe and Asn415Thr, were categorized as functionally severe. The age at presentation in the 2 patients carrying these variants was divergent and seemed to be driven by the patients' second pathogenic variants Gly1961Glu and c.5461-10T>C, respectively. Three variants, Val643Gly, Pro799Leu, and Val1433Ile were categorized as functionally moderate, and were found in patients with intermediate/late age at presentation. The remaining five variants were categorized as functionally normal/mild. Based on our data, c.614G>T p.(Cys205Phe), c.1244A>C p.(Asn415Thr), and c.2396C>T p.(Pro799Leu) were reclassified to (likely) pathogenic, while 4 of the functionally normal/mild variants could be reclassified to likely benign. Conclusions Functional analyses of ABCA4 variants are a helpful tool in variant classification and enable us to better predict the disease severity in patients with ABCA4-RDs.
Collapse
Affiliation(s)
- Sigrid Aslaksen
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Ingvild Aukrust
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Laurie Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | | | | | - Siren Berland
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Eyvind Rødahl
- Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Cecilie Bredrup
- Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Ragnheiður Bragadóttir
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Eirik Bratland
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Robert S. Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Per Morten Knappskog
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
2
|
Lin S, Vermeirsch S, Pontikos N, Martin-Gutierrez MP, Daich Varela M, Malka S, Schiff E, Knight H, Wright G, Jurkute N, Simcoe MJ, Yu-Wai-Man P, Moosajee M, Michaelides M, Mahroo OA, Webster AR, Arno G. Spectrum of Genetic Variants in the Most Common Genes Causing Inherited Retinal Disease in a Large Molecularly Characterized United Kingdom Cohort. Ophthalmol Retina 2024; 8:699-709. [PMID: 38219857 DOI: 10.1016/j.oret.2024.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/12/2023] [Accepted: 01/08/2024] [Indexed: 01/16/2024]
Abstract
PURPOSE Inherited retinal disease (IRD) is a leading cause of blindness. Recent advances in gene-directed therapies highlight the importance of understanding the genetic basis of these disorders. This study details the molecular spectrum in a large United Kingdom (UK) IRD patient cohort. DESIGN Retrospective study of electronic patient records. PARTICIPANTS Patients with IRD who attended the Genetics Service at Moorfields Eye Hospital between 2003 and July 2020, in whom a molecular diagnosis was identified. METHODS Genetic testing was undertaken via a combination of single-gene testing, gene panel testing, whole exome sequencing, and more recently, whole genome sequencing. Likely disease-causing variants were identified from entries within the genetics module of the hospital electronic patient record (OpenEyes Electronic Medical Record). Analysis was restricted to only genes listed in the Genomics England PanelApp R32 Retinal Disorders panel (version 3.24), which includes 412 genes associated with IRD. Manual curation ensured consistent variant annotation and included only plausible disease-associated variants. MAIN OUTCOME MEASURES Detailed analysis was performed for variants in the 5 most frequent genes (ABCA4, USH2A, RPGR, PRPH2, and BEST1), as well as for the most common variants encountered in the IRD study cohort. RESULTS We identified 4415 individuals from 3953 families with molecularly diagnosed IRD (variants in 166 genes). Of the families, 42.7% had variants in 1 of the 5 most common IRD genes. Complex disease alleles contributed to disease in 16.9% of affected families with ABCA4-associated retinopathy. USH2A exon 13 variants were identified in 43% of affected individuals with USH2A-associated IRD. Of the RPGR variants, 71% were clustered in the ORF15 region. PRPH2 and BEST1 variants were associated with a range of dominant and recessive IRD phenotypes. Of the 20 most prevalent variants identified, 5 were not in the most common genes; these included founder variants in CNGB3, BBS1, TIMP3, EFEMP1, and RP1. CONCLUSIONS We describe the most common pathogenic IRD alleles in a large single-center multiethnic UK cohort and the burden of disease, in terms of families affected, attributable to these variants. Our findings will inform IRD diagnoses in future patients and help delineate the cohort of patients eligible for gene-directed therapies under development. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Collapse
Affiliation(s)
- Siying Lin
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Sandra Vermeirsch
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Nikolas Pontikos
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Maria Pilar Martin-Gutierrez
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Malena Daich Varela
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Samantha Malka
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Elena Schiff
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Hannah Knight
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Genevieve Wright
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Neringa Jurkute
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom; Department of Neuro-Ophhalmology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Mark J Simcoe
- UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Patrick Yu-Wai-Man
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Mariya Moosajee
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Michel Michaelides
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Omar A Mahroo
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom; Department of Ophthalmology, St Thomas' Hospital, London, United Kingdom
| | - Andrew R Webster
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom
| | - Gavin Arno
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom; UCL Institute of Ophthalmology, University College London, United Kingdom.
| |
Collapse
|
3
|
Cornelis SS, IntHout J, Runhart EH, Grunewald O, Lin S, Corradi Z, Khan M, Hitti-Malin RJ, Whelan L, Farrar GJ, Sharon D, van den Born LI, Arno G, Simcoe M, Michaelides M, Webster AR, Roosing S, Mahroo OA, Dhaenens CM, Cremers FPM. Representation of Women Among Individuals With Mild Variants in ABCA4-Associated Retinopathy: A Meta-Analysis. JAMA Ophthalmol 2024; 142:463-471. [PMID: 38602673 PMCID: PMC11009866 DOI: 10.1001/jamaophthalmol.2024.0660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/27/2024] [Indexed: 04/12/2024]
Abstract
Importance Previous studies indicated that female sex might be a modifier in Stargardt disease, which is an ABCA4-associated retinopathy. Objective To investigate whether women are overrepresented among individuals with ABCA4-associated retinopathy who are carrying at least 1 mild allele or carrying nonmild alleles. Data Sources Literature data, data from 2 European centers, and a new study. Data from a Radboudumc database and from the Rotterdam Eye Hospital were used for exploratory hypothesis testing. Study Selection Studies investigating the sex ratio in individuals with ABCA4-AR and data from centers that collected ABCA4 variant and sex data. The literature search was performed on February 1, 2023; data from the centers were from before 2023. Data Extraction and Synthesis Random-effects meta-analyses were conducted to test whether the proportions of women among individuals with ABCA4-associated retinopathy with mild and nonmild variants differed from 0.5, including subgroup analyses for mild alleles. Sensitivity analyses were performed excluding data with possibly incomplete variant identification. χ2 Tests were conducted to compare the proportions of women in adult-onset autosomal non-ABCA4-associated retinopathy and adult-onset ABCA4-associated retinopathy and to investigate if women with suspected ABCA4-associated retinopathy are more likely to obtain a genetic diagnosis. Data analyses were performed from March to October 2023. Main Outcomes and Measures Proportion of women per ABCA4-associated retinopathy group. The exploratory testing included sex ratio comparisons for individuals with ABCA4-associated retinopathy vs those with other autosomal retinopathies and for individuals with ABCA4-associated retinopathy who underwent genetic testing vs those who did not. Results Women were significantly overrepresented in the mild variant group (proportion, 0.59; 95% CI, 0.56-0.62; P < .001) but not in the nonmild variant group (proportion, 0.50; 95% CI, 0.46-0.54; P = .89). Sensitivity analyses confirmed these results. Subgroup analyses on mild variants showed differences in the proportions of women. Furthermore, in the Radboudumc database, the proportion of adult women among individuals with ABCA4-associated retinopathy (652/1154 = 0.56) was 0.10 (95% CI, 0.05-0.15) higher than among individuals with other retinopathies (280/602 = 0.47). Conclusions and Relevance This meta-analysis supports the likelihood that sex is a modifier in developing ABCA4-associated retinopathy for individuals with a mild ABCA4 allele. This finding may be relevant for prognosis predictions and recurrence risks for individuals with ABCA4-associated retinopathy. Future studies should further investigate whether the overrepresentation of women is caused by differences in the disease mechanism, by differences in health care-seeking behavior, or by health care discrimination between women and men with ABCA4-AR.
Collapse
Affiliation(s)
- Stéphanie S. Cornelis
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joanna IntHout
- Radboud Institute for Health Sciences, Department for Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Esmee H. Runhart
- Rotterdam Ophthalmic Institute, The Rotterdam Eye Hospital, Rotterdam, the Netherlands
| | - Olivier Grunewald
- Lille Neuroscience & Cognition, University of Lille, Inserm, CHU Lille, Lille, France
| | - Siying Lin
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
| | | | - Laura Whelan
- Smurfit Institute of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - G. Jane Farrar
- Smurfit Institute of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Gavin Arno
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Mark Simcoe
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Michel Michaelides
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Andrew R. Webster
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Omar A. Mahroo
- National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Claire-Marie Dhaenens
- Lille Neuroscience & Cognition, University of Lille, Inserm, CHU Lille, Lille, France
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| |
Collapse
|
4
|
Sabharwal J, Liu TYA, Antonio-Aguirre B, Abousy M, Patel T, Cai CX, Jones CK, Singh MS. Automated identification of fleck lesions in Stargardt disease using deep learning enhances lesion detection sensitivity and enables morphometric analysis of flecks. Br J Ophthalmol 2024:bjo-2023-323592. [PMID: 38408857 DOI: 10.1136/bjo-2023-323592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 01/20/2024] [Indexed: 02/28/2024]
Abstract
PURPOSE To classify fleck lesions and assess artificial intelligence (AI) in identifying flecks in Stargardt disease (STGD). METHODS A retrospective study of 170 eyes from 85 consecutive patients with confirmed STGD. Fundus autofluorescence images were extracted, and flecks were manually outlined. A deep learning model was trained, and a hold-out testing subset was used to compare with manually identified flecks and for graders to assess. Flecks were clustered using K-means clustering. RESULTS Of the 85 subjects, 45 were female, and the median age was 37 years (IQR 25-59). A subset of subjects (n=41) had clearly identifiable fleck lesions, and an AI was successfully trained to identify these lesions (average Dice score of 0.53, n=18). The AI segmentation had smaller (0.018 compared with 0.034 mm2, p<0.001) but more numerous flecks (75.5 per retina compared with 40.0, p<0.001), but the total size of flecks was not different. The AI model had higher sensitivity to detect flecks but resulted in more false positives. There were two clusters of flecks based on morphology: broadly, one cluster of small round flecks and another of large amorphous flecks. The per cent frequency of small round flecks negatively correlated with subject age (r=-0.31, p<0.005). CONCLUSIONS AI-based detection of flecks shows greater sensitivity than human graders but with a higher false-positive rate. With further optimisation to address current shortcomings, this approach could be used to prescreen subjects for clinical research. The feasibility and utility of quantifying fleck morphology in conjunction with AI-based segmentation as a biomarker of progression require further study.
Collapse
Affiliation(s)
| | | | | | - Mya Abousy
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Tapan Patel
- Johns Hopkins Wilmer Eye Institute, Baltimore, Maryland, USA
| | - Cindy X Cai
- Johns Hopkins Wilmer Eye Institute, Baltimore, Maryland, USA
| | - Craig K Jones
- The Malone Center for Engineering in Healthcare, Johns Hopkins University, Baltimore, Maryland, USA
| | - Mandeep S Singh
- Johns Hopkins Wilmer Eye Institute, Baltimore, Maryland, USA
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| |
Collapse
|
5
|
Xiao YL, Wu Y, Tang W. An adenine base editor variant expands context compatibility. Nat Biotechnol 2024:10.1038/s41587-023-01994-3. [PMID: 38168987 DOI: 10.1038/s41587-023-01994-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 09/15/2023] [Indexed: 01/05/2024]
Abstract
Adenine base editors (ABEs) are precise gene-editing agents that convert A:T pairs into G:C through a deoxyinosine intermediate. Existing ABEs function most effectively when the target A is in a TA context. Here we evolve the Escherichia coli transfer RNA-specific adenosine deaminase (TadA) to generate TadA8r, which extends potent deoxyadenosine deamination to RA (R = A or G) and is faster in processing GA than TadA8.20 and TadA8e, the two most active TadA variants reported so far. ABE8r, comprising TadA8r and a Streptococcus pyogenes Cas9 nickase, expands the editing window at the protospacer adjacent motif-distal end and outperforms ABE7.10, ABE8.20 and ABE8e in correcting disease-associated G:C-to-A:T transitions in the human genome, with a controlled off-target profile. We show ABE8r-mediated editing of clinically relevant sites that are poorly accessed by existing editors, including sites in PCSK9, whose disruption reduces low-density lipoprotein cholesterol, and ABCA4-p.Gly1961Glu, the most frequent mutation in Stargardt disease.
Collapse
Affiliation(s)
- Yu-Lan Xiao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
| | - Yuan Wu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
| | - Weixin Tang
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA.
| |
Collapse
|
6
|
Kadyshev VV, Alekseeva EA, Strelnikov VV, Stepanova AA, Polyakov AV, Marakhonov AV, Kutsev SI, Zinchenko RA. Major Contribution of c.[1622T>C;3113C>T] Complex Allele and c.5882G>A Variant in ABCA4-Related Retinal Dystrophy in an Eastern European Population. Int J Mol Sci 2023; 24:16231. [PMID: 38003421 PMCID: PMC10671488 DOI: 10.3390/ijms242216231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/05/2023] [Accepted: 11/11/2023] [Indexed: 11/26/2023] Open
Abstract
Inherited retinal diseases (IRDs) constitute a prevalent group of inherited ocular disorders characterized by marked genetic diversity alongside moderate clinical variability. Among these, ABCA4-related eye pathology stands as a prominent form affecting the retina. In this study, we conducted an in-depth analysis of 96 patients harboring ABCA4 variants in the European part of Russia. Notably, the complex allele c.[1622T>C;3113C>T] (p.Leu541Pro;Ala1038Val, or L541P;A1038V) and the variant c.5882G>A (p.Gly1961Glu or G1961E) emerged as primary contributors to this ocular pathology within this population. Additionally, we elucidated distinct disease progression characteristics associated with the G1961E variant. Furthermore, our investigation revealed that patients with loss-of-function variants in ABCA4 were more inclined to develop phenotypes distinct from Stargardt disease. These findings provide crucial insights into the genetic and clinical landscape of ABCA4-related retinal dystrophies in this specific population.
Collapse
Affiliation(s)
- Vitaly V. Kadyshev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (E.A.A.); (V.V.S.); (A.A.S.); (A.V.P.); (A.V.M.); (S.I.K.); (R.A.Z.)
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Whelan L, Dockery A, Stephenson KAJ, Zhu J, Kopčić E, Post IJM, Khan M, Corradi Z, Wynne N, O' Byrne JJ, Duignan E, Silvestri G, Roosing S, Cremers FPM, Keegan DJ, Kenna PF, Farrar GJ. Detailed analysis of an enriched deep intronic ABCA4 variant in Irish Stargardt disease patients. Sci Rep 2023; 13:9380. [PMID: 37296172 PMCID: PMC10256698 DOI: 10.1038/s41598-023-35889-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Over 15% of probands in a large cohort of more than 1500 inherited retinal degeneration patients present with a clinical diagnosis of Stargardt disease (STGD1), a recessive form of macular dystrophy caused by biallelic variants in the ABCA4 gene. Participants were clinically examined and underwent either target capture sequencing of the exons and some pathogenic intronic regions of ABCA4, sequencing of the entire ABCA4 gene or whole genome sequencing. ABCA4 c.4539 + 2028C > T, p.[= ,Arg1514Leufs*36] is a pathogenic deep intronic variant that results in a retina-specific 345-nucleotide pseudoexon inclusion. Through analysis of the Irish STGD1 cohort, 25 individuals across 18 pedigrees harbour ABCA4 c.4539 + 2028C > T and another pathogenic variant. This includes, to the best of our knowledge, the only two homozygous patients identified to date. This provides important evidence of variant pathogenicity for this deep intronic variant, highlighting the value of homozygotes for variant interpretation. 15 other heterozygous incidents of this variant in patients have been reported globally, indicating significant enrichment in the Irish population. We provide detailed genetic and clinical characterization of these patients, illustrating that ABCA4 c.4539 + 2028C > T is a variant of mild to intermediate severity. These results have important implications for unresolved STGD1 patients globally with approximately 10% of the population in some western countries claiming Irish heritage. This study exemplifies that detection and characterization of founder variants is a diagnostic imperative.
Collapse
Affiliation(s)
- Laura Whelan
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland.
| | - Adrian Dockery
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
- Next Generation Sequencing Laboratory, Pathology Department, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Kirk A J Stephenson
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Julia Zhu
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Ella Kopčić
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Iris J M Post
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- International Max Planck Research School for Language Sciences, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Niamh Wynne
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - James J O' Byrne
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
- International Max Planck Research School for Language Sciences, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- National Centre for Inherited Metabolic Disorders, The Mater Misericordiae University Hospital, Dublin 7, Ireland
- School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Emma Duignan
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - Giuliana Silvestri
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
- School of Medicine, University College Dublin, Dublin 4, Ireland
- Department of Ophthalmology, The Royal Victoria Hospital, Belfast, Northern Ireland, UK
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - David J Keegan
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Paul F Kenna
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - G Jane Farrar
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
8
|
Cevik S, Biswas SB, Biswas-Fiss EE. Structural and Pathogenic Impacts of ABCA4 Variants in Retinal Degenerations-An In-Silico Study. Int J Mol Sci 2023; 24:ijms24087280. [PMID: 37108442 PMCID: PMC10138569 DOI: 10.3390/ijms24087280] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
The retina-specific ATP-binding cassette transporter protein ABCA4 is responsible for properly continuing the visual cycle by removing toxic retinoid byproducts of phototransduction. Functional impairment caused by ABCA4 sequence variations is the leading cause of autosomal recessive inherited retinal disorders, including Stargardt disease, retinitis pigmentosa, and cone-rod dystrophy. To date, more than 3000 ABCA4 genetic variants have been identified, approximately 40 percent of which have not been able to be classified for pathogenicity assessments. This study examined 30 missense ABCA4 variants using AlphaFold2 protein modeling and computational structure analysis for pathogenicity prediction. All variants classified as pathogenic (n = 10) were found to have deleterious structural consequences. Eight of the ten benign variants were structurally neutral, while the remaining two resulted in mild structural changes. This study's results provided multiple lines of computational pathogenicity evidence for eight ABCA4 variants of uncertain clinical significance. Overall, in silico analyses of ABCA4 can provide a valuable tool for understanding the molecular mechanisms of retinal degeneration and their pathogenic impact.
Collapse
Affiliation(s)
- Senem Cevik
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Subhasis B Biswas
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Esther E Biswas-Fiss
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| |
Collapse
|
9
|
He D, Tao L, Cai B, Chen X, Wang Y, Li S, Liao C, Chen Y, Chen J, Liu Z, Wu Y. eIF2α incites photoreceptor cell and retina damage by all-trans-retinal. J Biol Chem 2023; 299:104686. [PMID: 37031820 DOI: 10.1016/j.jbc.2023.104686] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/21/2023] [Accepted: 03/31/2023] [Indexed: 04/11/2023] Open
Abstract
Dry age-related macular degeneration (AMD) and recessive Stargardt's disease (STGD1) lead to irreversible blindness in humans. The accumulation of all-trans-retinal (atRAL) induced by chaos in visual cycle is closely associated with retinal atrophy in dry AMD and STGD1, but its critical downstream signaling molecules remain ambiguous. Here, we reported that activation of eukaryotic translation initiation factor 2α (eIF2α) by atRAL promoted retinal degeneration and photoreceptor loss through activating c-Jun N-terminal kinase (JNK) signaling-dependent apoptosis and gasdermin E (GSDME)-mediated pyroptosis. We determined that eIF2α activation by atRAL in photoreceptor cells resulted from endoplasmic reticulum (ER) homeostasis disruption caused at least in part by reactive oxygen species (ROS) production, and it activated JNK signaling independent of and dependent on activating transcription factor 4 (ATF4) and the ATF4/transcription factor C/EBP homologous protein (CHOP) axis. CHOP overexpression induced apoptosis of atRAL-loaded photoreceptor cells through activating JNK signaling rather than inhibiting the expression of anti-apoptotic gene Bcl2. JNK activation by eIF2α facilitated photoreceptor cell apoptosis caused by atRAL via caspase-3 activation and DNA damage. Additionally, we demonstrated that eIF2α was activated in neural retina of light-exposed Abca4-/-Rdh8-/- mice, a model that shows severe defects in atRAL clearance and displays primary features of human dry AMD and STGD1. Of note, inhibition of eIF2α activation by salubrinal effectively ameliorated retinal degeneration and photoreceptor apoptosis in Abca4-/-Rdh8-/- mice upon light exposure. The results of this study suggest that eIF2α is an important target to develop drug therapies for the treatment of dry AMD and STGD1.
Collapse
Affiliation(s)
- Danxue He
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Lei Tao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Binxiang Cai
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou, China
| | - Yan Wang
- Department of Ophthalmology, South China Hospital, Medical School, Shenzhen University, Shenzhen, China
| | - Shiying Li
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Chunyan Liao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Yuling Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Jingmeng Chen
- School of Medicine, Xiamen University, Xiamen, China
| | - Zuguo Liu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, China; Shenzhen Research Institute of Xiamen University, Shenzhen, China; Xiamen Eye Center of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
| |
Collapse
|
10
|
Chen LJ, Chen ZJ, Pang CP. Latest Development on Genetics of Common Retinal Diseases. Asia Pac J Ophthalmol (Phila) 2023; 12:228-251. [PMID: 36971708 DOI: 10.1097/apo.0000000000000592] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/15/2022] [Indexed: 03/29/2023] Open
Abstract
Many complex forms of retinal diseases are common and pan-ethnic in occurrence. Among them, neovascular age-related macular degeneration, polypoidal choroidal vasculopathy, and central serous choroid retinopathy involve both choroidopathy and neovascularization with multifactorial etiology. They are sight-threatening and potentially blinding. Early treatment is crucial to prevent disease progression. To understand their genetic basis, candidate gene mutational and association analyses, linkage analysis, genome-wide association studies, transcriptome analysis, next-generation sequencing, which includes targeted deep sequencing, whole-exome sequencing, and whole genome sequencing have been conducted. Advanced genomic technologies have led to the identification of many associated genes. But their etiologies are attributed to complicated interactions of multiple genetic and environmental risk factors. Onset and progression of neovascular age-related macular degeneration and polypoidal choroidal vasculopathy are affected by aging, smoking, lifestyle, and variants in over 30 genes. Although some genetic associations have been confirmed and validated, individual genes or polygenic risk markers of clinical value have not been established. The genetic architectures of all these complex retinal diseases that involve sequence variant quantitative trait loci have not been fully delineated. Recently artificial intelligence is making an impact in the collection and advanced analysis of genetic, investigative, and lifestyle data for the establishment of predictive factors for the risk of disease onset, progression, and prognosis. This will contribute to individualized precision medicine for the management of complex retinal diseases.
Collapse
Affiliation(s)
- Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital Eye Centre, Hong Kong, China
- Hong Kong Hub of Pediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
| | - Zhen Ji Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Hong Kong Hub of Pediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
- Joint Shantou International Eye Centre of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| |
Collapse
|
11
|
Chen C, Yang K, He D, Yang B, Tao L, Chen J, Wu Y. Induction of ferroptosis by HO-1 contributes to retinal degeneration in mice with defective clearance of all-trans-retinal. Free Radic Biol Med 2023; 194:245-254. [PMID: 36509314 DOI: 10.1016/j.freeradbiomed.2022.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
The accumulation of all-trans-retinal (atRAL) in photoreceptors and the retinal pigment epithelium (RPE), which is induced by chaos in visual (retinoid) cycle, is closely associated with the pathogenesis of dry age-related macular degeneration (AMD) and autosomal recessive Stargardt's disease (STGD1). Although we have reported that the induction of ferroptosis by atRAL is an important cause of photoreceptor loss, but its mechanisms still remain unclear. In this study, we identified heme oxygenase-1 (HO-1) as an inducer of photoreceptor ferroptosis elicited by atRAL. In atRAL-loaded photoreceptor cells, inhibition of Kelch-like ECH-associated protein 1 (KEAP1) at least in part by reactive oxygen species (ROS) production evoked the release of nuclear factor-erythroid 2-related factor-2 (NRF2) from KEAP1, followed by the translocation of active NRF2 into the nucleus where it promoted the transcription of the Ho-1 gene, thereby leading to HO-1 overexpression in the cytosol. A significant elevation of Fe2+ levels in photoreceptor cells resulted from activation of HO-1 by atRAL, and it facilitated ROS overproduction and then triggered ferroptotic cell death through ROS-mediated lipid peroxidation. Both treatment with HO-1 repressor Zinc protoporphyrin IX (ZnPP) and knockout of Ho-1 gene clearly rescued photoreceptor cells against ferroptosis arising from atRAL overload. Light-exposed Abca4-/-Rdh8-/- mice rapidly display severe defects in atRAL clearance, and serve as an acute model of dry AMD and STGD1. HO-1 activation was distinctly observed in neural retina of Abca4-/-Rdh8-/- mice after exposure to light, and it was visibly relieved by intraperitoneally injected ferroptosis inhibitor ferrostatin-1. More notably, intraperitoneal administration of ZnPP effectively alleviated both photoreceptor degeneration and RPE atrophy in Abca4-/-Rdh8-/- mice in response to light exposure by repressing HO-1-mediated ferroptosis. Our study suggests that HO-1 is a key factor that regulates atRAL-induced ferroptosis in photoreceptors and the RPE, and its inhibition may hold promises for the therapy of dry AMD and STGD1.
Collapse
Affiliation(s)
- Chao Chen
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Kunhuan Yang
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Danxue He
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Bo Yang
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Lei Tao
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Jingmeng Chen
- School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China
| | - Yalin Wu
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Fujian Engineering and Research Center of Eye Regenerative Medicine, Department of Ophthalmology, Xiang'an Hospital of Xiamen University, Eye Institute of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, Fujian, China; Shenzhen Research Institute of Xiamen University, Shenzhen, 518063, Guangdong, China; Xiamen Eye Center of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361001, Fujian, China.
| |
Collapse
|
12
|
Elsayed MEAA, Kaukonen M, Kiraly P, Kapetanovic JC, MacLaren RE. Potential CRISPR Base Editing Therapeutic Options in a Sorsby Fundus Dystrophy Patient. Genes (Basel) 2022; 13:2103. [PMID: 36421778 PMCID: PMC9690532 DOI: 10.3390/genes13112103] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 07/30/2023] Open
Abstract
TIMP3 mutations are associated with early-onset macular choroidal neovascularisation for which no treatment currently exists. CRISPR base editing, with its ability to irreversibly correct point mutations by chemical modification of nucleobases at DNA level, may be a therapeutic option. We report a bioinformatic analysis of potential therapeutic options in a patient presenting with Sorsby fundus dystrophy. Genetic testing in a 35-year-old gentleman with bilateral macular choroidal neovascularisation revealed the patient to be heterozygous for a TIMP3 variant c.610A>T, p.(Ser204Cys). Using a glycosylase base editor (GBE), another DNA-edit could be introduced that would revert the variant back to wild-type on amino acid level. Alternatively, the mutated residue could be changed to another amino acid that would be better tolerated, and for that, an available 'NG'-PAM site was found to be available for the SpCas9-based adenine base editor (ABE) that would introduce p.(Ser204Arg). In silico analyses predicted this variant to be non-pathogenic; however, a bystander edit, p.Ile205Thr, would be introduced. This case report highlights the importance of considering genetic testing in young patients with choroidal neovascularisation, particularly within the context of a strong family history of presumed wet age-related macular degeneration, and describes potential therapeutic options.
Collapse
Affiliation(s)
| | - Maria Kaukonen
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX3 9DU, UK
| | - Peter Kiraly
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Jasmina Cehajic Kapetanovic
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX3 9DU, UK
| | - Robert E. MacLaren
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX3 9DU, UK
| |
Collapse
|
13
|
Lugo-Merly A, Molina Thurin LJ, Izquierdo-Encarnacion NJ, Casillas-Murphy SM, Oliver-Cruz A. Stargardt Disease Due to an Intronic Mutation in the ABCA4: A Case Report. Int Med Case Rep J 2022; 15:693-698. [DOI: 10.2147/imcrj.s391001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/23/2022] [Indexed: 11/30/2022] Open
|
14
|
Stradiotto E, Allegrini D, Fossati G, Raimondi R, Sorrentino T, Tripepi D, Barone G, Inforzato A, Romano MR. Genetic Aspects of Age-Related Macular Degeneration and Their Therapeutic Potential. Int J Mol Sci 2022; 23:13280. [PMID: 36362067 PMCID: PMC9653831 DOI: 10.3390/ijms232113280] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/05/2022] [Accepted: 10/28/2022] [Indexed: 08/27/2023] Open
Abstract
Age-related macular degeneration (AMD) is a complex and multifactorial disease, resulting from the interaction of environmental and genetic factors. The continuous discovery of associations between genetic polymorphisms and AMD gives reason for the pivotal role attributed to the genetic component to its development. In that light, genetic tests and polygenic scores have been created to predict the risk of development and response to therapy. Still, none of them have yet been validated. Furthermore, there is no evidence from a clinical trial that the determination of the individual genetic structure can improve treatment outcomes. In this comprehensive review, we summarize the polymorphisms of the main pathogenetic ways involved in AMD development to identify which of them constitutes a potential therapeutic target. As complement overactivation plays a major role, the modulation of targeted complement proteins seems to be a promising therapeutic approach. Herein, we summarize the complement-modulating molecules now undergoing clinical trials, enlightening those in an advanced phase of trial. Gene therapy is a potential innovative one-time treatment, and its relevance is quickly evolving in the field of retinal diseases. We describe the state of the art of gene therapies now undergoing clinical trials both in the field of complement-suppressors and that of anti-VEGF.
Collapse
Affiliation(s)
- Elisa Stradiotto
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Davide Allegrini
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Giovanni Fossati
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Raffaele Raimondi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Tania Sorrentino
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Domenico Tripepi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Gianmaria Barone
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| | - Antonio Inforzato
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano-Milan, Italy
| | - Mario R. Romano
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072 Milan, Italy
- Department of Ophthalmology, Eye Unit Humanitas Gavazzeni-Castelli, Via Mazzini 11, 24128 Bergamo, Italy
| |
Collapse
|
15
|
Benson MD, Feldman CB, Zein WM. Evolution of focal choroidal excavation in ABCA4-related retinopathy. Am J Ophthalmol Case Rep 2022; 28:101740. [DOI: 10.1016/j.ajoc.2022.101740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 11/05/2022] Open
|
16
|
Farnoodian M, Bose D, Khristov V, Susaimanickam PJ, Maddileti S, Mariappan I, Abu-Asab M, Campos M, Villasmil R, Wan Q, Maminishkis A, McGaughey D, Barone F, Gundry RL, Riordon DR, Boheler KR, Sharma R, Bharti K. Cell-autonomous lipid-handling defects in Stargardt iPSC-derived retinal pigment epithelium cells. Stem Cell Reports 2022; 17:2438-2450. [DOI: 10.1016/j.stemcr.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
|
17
|
Thirunavukarasu AJ, Ross AC, Gilbert RM. Vitamin A, systemic T-cells, and the eye: Focus on degenerative retinal disease. Front Nutr 2022; 9:914457. [PMID: 35923205 PMCID: PMC9339908 DOI: 10.3389/fnut.2022.914457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
The first discovered vitamin, vitamin A, exists in a range of forms, primarily retinoids and provitamin carotenoids. The bioactive forms of vitamin A, retinol and retinoic acid, have many critical functions in body systems including the eye and immune system. Vitamin A deficiency is associated with dysfunctional immunity, and presents clinically as a characteristic ocular syndrome, xerophthalmia. The immune functions of vitamin A extend to the gut, where microbiome interactions and nutritional retinoids and carotenoids contribute to the balance of T cell differentiation, thereby determining immune status and contributing to inflammatory disease around the whole body. In the eye, degenerative conditions affecting the retina and uvea are influenced by vitamin A. Stargardt’s disease (STGD1; MIM 248200) is characterised by bisretinoid deposits such as lipofuscin, produced by retinal photoreceptors as they use and recycle a vitamin A-derived chromophore. Age-related macular degeneration features comparable retinal deposits, such as drusen featuring lipofuscin accumulation; and is characterised by parainflammatory processes. We hypothesise that local parainflammatory processes secondary to lipofuscin deposition in the retina are mediated by T cells interacting with dietary vitamin A derivatives and the gut microbiome, and outline the current evidence for this. No cures exist for Stargardt’s or age-related macular degeneration, but many vitamin A-based therapeutic approaches have been or are being trialled. The relationship between vitamin A’s functions in systemic immunology and the eye could be further exploited, and further research may seek to leverage the interactions of the gut-eye immunological axis.
Collapse
Affiliation(s)
- Arun J. Thirunavukarasu
- Corpus Christi College, University of Cambridge, Cambridge, United Kingdom
- University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - A. Catharine Ross
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Rose M. Gilbert
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- *Correspondence: Rose M. Gilbert,
| |
Collapse
|
18
|
Kamenarova K, Mihova K, Veleva N, Mermeklieva E, Mihaylova B, Dimitrova G, Oscar A, Shandurkov I, Cherninkova S, Kaneva R. Panel-based next-generation sequencing identifies novel mutations in Bulgarian patients with inherited retinal dystrophies. Mol Genet Genomic Med 2022; 10:e1997. [PMID: 35656873 PMCID: PMC9356554 DOI: 10.1002/mgg3.1997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 04/07/2022] [Accepted: 05/13/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Next-generation sequencing (NGS)-based method is being used broadly for genetic testing especially for clinically and genetically heterogeneous disorders, such as inherited retinal degenerations (IRDs) but still not routinely used for molecular diagnostics in Bulgaria. Consequently, the purpose of this study was to evaluate the effectiveness of a molecular diagnostic approach, based on targeted NGS for the identification of the disease-causing mutations in 16 Bulgarian patients with different IRDs. METHODS We applied a customized NGS panel, including 125 genes associated with retinal and other eye diseases to the patients with hereditary retinopathies. RESULTS Systematic filtering approach coupled with copy number variation analysis and segregation study lead to the identification of 16 pathogenic and likely pathogenic variants in 12/16 (75%) of IRD patients, 2 of which novel (12.5%): ABCA4-c.668delA (p.K223Rfs18) and RР1-c.2015dupA (p.K673Efs*25). Mutations in the ABCA4, PRPH2, USH2A, BEST1, RР1, CDHR1, and RHO genes were detected reaching a diagnostic yield between 42.9% for Retinitis pigmentosa cases and 100% for macular degeneration, Usher syndrome, and cone-rod dystrophy patients. CONCLUSION Our results confirm the usefulness of targeted NGS approach based on frequently mutated genes as a comprehensive and successful genetic diagnostic tool for IRDs with significant impact on patients counseling.
Collapse
Affiliation(s)
- Kunka Kamenarova
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria.,Laboratory of Genomic Diagnostics, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria
| | - Kalina Mihova
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria.,Laboratory of Genomic Diagnostics, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria
| | - Nevyana Veleva
- Department of Ophthalmology, University Hospital "Alexandrovska", Medical University of Sofia, Sofia, Bulgaria
| | - Elena Mermeklieva
- Clinic of Ophthalmology, University Hospital "Lozenetz", Medical Faculty, Sofia University "St. Kliment Ohridski", Sofia, Bulgaria
| | | | - Galina Dimitrova
- Department of Ophthalmology, University Hospital "Alexandrovska", Medical University of Sofia, Sofia, Bulgaria
| | - Alexander Oscar
- Department of Ophthalmology, University Hospital "Alexandrovska", Medical University of Sofia, Sofia, Bulgaria
| | | | - Sylvia Cherninkova
- Department of Neurology, University hospital "Alexandrovska", Medical University of Sofia, Sofia, Bulgaria
| | - Radka Kaneva
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria.,Laboratory of Genomic Diagnostics, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria
| |
Collapse
|
19
|
Xiang L, Zhang J, Rao FQ, Yang QL, Zeng HY, Huang SH, Xie ZX, Lv JN, Lin D, Chen XJ, Wu KC, Lu F, Huang XF, Chen Q. Depletion of miR-96 Delays, But Does Not Arrest, Photoreceptor Development in Mice. Invest Ophthalmol Vis Sci 2022; 63:24. [PMID: 35481839 PMCID: PMC9055555 DOI: 10.1167/iovs.63.4.24] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose Abundant retinal microRNA-183 cluster (miR-183C) has been reported to be a key player in photoreceptor development and functionality in mice. However, whether there is a protagonist in this cluster remains unclear. Here, we used a mutant mouse model to study the role of miR-96, a member of miR-183C, in photoreceptor development and functionality. Methods The mature miR-96 sequence was removed using the CRISPR/Cas9 genome-editing system. Electroretinogram (ERG) and optical coherence tomography (OCT) investigated the changes in structure and function in mouse retinas. Immunostaining determined the localization and morphology of the retinal cells. RNA sequencing was conducted to observe retinal transcription alterations. Results The miR-96 mutant mice exhibited cone developmental delay, as occurs in miR-183/96 double knockout mice. Immunostaining of cone-specific marker genes revealed cone nucleus mislocalization and exiguous Opn1mw/Opn1sw in the mutant (MT) mouse outer segments at postnatal day 10. Interestingly, this phenomenon could be relieved in the adult stages. Transcriptome analysis revealed activation of microtubule-, actin filament–, and cilia-related pathways, further supporting the findings. Based on ERG and OCT results at different ages, the MT mice displayed developmental delay not only in cones but also in rods. In addition, a group of miR-96 potential direct and indirect target genes was summarized for interpretation and further studies of miR-96–related retinal developmental defects. Conclusions Depletion of miR-96 delayed but did not arrest photoreceptor development in mice. This miRNA is indispensable for mouse photoreceptor maturation, especially for cones.
Collapse
Affiliation(s)
- Lue Xiang
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China
| | - Juan Zhang
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Feng-Qin Rao
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,School of Pharmaceutical Sciences of Wenzhou Medical University, Wenzhou, China
| | - Qiao-Li Yang
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Hui-Yi Zeng
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Sheng-Hai Huang
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zhen-Xiang Xie
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ji-Neng Lv
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China
| | - Dan Lin
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xue-Jiao Chen
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China
| | - Kun-Chao Wu
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fan Lu
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China
| | - Xiu-Feng Huang
- The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qi Chen
- School of Ophthalmology and Optometry, School of Biomedical Engineering, Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, China
| |
Collapse
|
20
|
Molecular analysis of ABCA4 gene in an Iranian cohort with Stargardt disease. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2021.101450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
21
|
Piotter E, McClements ME, MacLaren RE. The Scope of Pathogenic ABCA4 Mutations Targetable by CRISPR DNA Base Editing Systems—A Systematic Review. Front Genet 2022; 12:814131. [PMID: 35154257 PMCID: PMC8830518 DOI: 10.3389/fgene.2021.814131] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/14/2021] [Indexed: 12/26/2022] Open
Abstract
Stargardt macular dystrophy (STGD1) is the most common form of inherited childhood blindness worldwide and for which no current treatments exist. It is an autosomal recessive disease caused by mutations in ABCA4. To date, a variety of gene supplementation approaches have been tested to create a therapy, with some reaching clinical trials. New technologies, such as CRISPR-Cas based editing systems, provide an exciting frontier for addressing genetic disease by allowing targeted DNA or RNA base editing of pathogenic mutations. ABCA4 has ∼1,200 known pathogenic mutations, of which ∼63% are transition mutations amenable to this editing technology. In this report, we screened the known “pathogenic” and “likely pathogenic” mutations in ABCA4 from available data in gnomAD, Leiden Open Variation Database (LOVD), and ClinVar for potential PAM sites of relevant base editors, including Streptococcus pyogenes Cas (SpCas), Staphylococcus aureus Cas (SaCas), and the KKH variant of SaCas (Sa-KKH). Overall, of the mutations screened, 53% (ClinVar), 71% (LOVD), and 71% (gnomAD), were editable, pathogenic transition mutations, of which 35–47% had “ideal” PAM sites. Of these mutations, 16–20% occur within a range of multiple PAM sites, enabling a variety of editing strategies. Further, in relevant patient data looking at three cohorts from Germany, Denmark, and China, we find that 44–76% of patients, depending on the presence of complex alleles, have at least one transition mutation with a nearby SaCas, SpCas, or Sa-KKH PAM site, which would allow for potential DNA base editing as a treatment strategy. Given the complexity of the genetic landscape of Stargardt, these findings provide a clearer understanding of the potential for DNA base editing approaches to be applied as ABCA4 gene therapy strategies.
Collapse
Affiliation(s)
- Elena Piotter
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- *Correspondence: Elena Piotter,
| | - Michelle E. McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust and NIHR Biomedical Research Centre, Oxford, United Kingdom
| |
Collapse
|
22
|
Darbari E, Ahmadieh H, Daftarian N, Rezaei Kanavi M, Suri F, Sabbaghi H, Elahi E. Mutation Screening of Six Exons of ABCA4 in Iranian Stargardt Disease Patients. J Ophthalmic Vis Res 2022; 17:51-58. [PMID: 35194496 PMCID: PMC8850862 DOI: 10.18502/jovr.v17i1.10170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 05/21/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose Stargardt disease type 1 (STGD1) is a recessively inherited retinal disorder that can cause severe visual impairment. ABCA4 mutations are the usual cause of STGD1. ABCA4 codes a transporter protein exclusively expressed in retinal photoreceptor cells. The genecontains 50 exons. Mutations are most frequent in exons 3, 6, 12, and 13, and exons 10 and 42 each contain two common variations. We aimed to screen these exons for mutations in Iranian STGD1 patients. Methods Eighteen STGD1 patients were recruited for genetic analysis. Diagnosis by retina specialists was based on standard criteria, including accumulation of lipofuscin. The six ABCA4 exons were PCR amplified and sequenced by the Sanger method. Results One or more ABCA4-mutated alleles were identified in 5 of the 18 patients (27.8%). Five different mutations including two splice site (c.1356+1G>A and c.5836-2A>G) and three missense mutations (p.Gly1961Glu, p.Gly1961Arg, and p.Gly550Arg) were found. The p.Gly1961Glu mutation was the only mutation observed in two patients. Conclusion As ABCA4 mutations in exons 6, 12, 10, and 42 were identified in approximately 25% of the patients studied, these may be appropriate exons for screening projects. As in other populations, STDG1 causative ABCA4 mutations are heterogeneous among Iranian patients, and p.Gly1961Glu may be relatively frequent.
Collapse
Affiliation(s)
- Ensieh Darbari
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Ahmadieh
- Opthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid University of Medical Sciences, Tehran, Iran.,Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Narsis Daftarian
- Opthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid University of Medical Sciences, Tehran, Iran.,Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Opthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid University of Medical Sciences, Tehran, Iran.,Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Suri
- Opthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid University of Medical Sciences, Tehran, Iran
| | - Hamideh Sabbaghi
- Ophthalmic Epidemiology Research Center, Research Institute for ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elahe Elahi
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| |
Collapse
|
23
|
Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
Collapse
Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
| |
Collapse
|
24
|
Molday RS, Garces FA, Scortecci JF, Molday LL. Structure and function of ABCA4 and its role in the visual cycle and Stargardt macular degeneration. Prog Retin Eye Res 2021; 89:101036. [PMID: 34954332 DOI: 10.1016/j.preteyeres.2021.101036] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/07/2021] [Accepted: 12/13/2021] [Indexed: 12/17/2022]
Abstract
ABCA4 is a member of the superfamily of ATP-binding cassette (ABC) transporters that is preferentially localized along the rim region of rod and cone photoreceptor outer segment disc membranes. It uses the energy from ATP binding and hydrolysis to transport N-retinylidene-phosphatidylethanolamine (N-Ret-PE), the Schiff base adduct of retinal and phosphatidylethanolamine, from the lumen to the cytoplasmic leaflet of disc membranes. This ensures that all-trans-retinal and excess 11-cis-retinal are efficiently cleared from photoreceptor cells thereby preventing the accumulation of toxic retinoid compounds. Loss-of-function mutations in the gene encoding ABCA4 cause autosomal recessive Stargardt macular degeneration, also known as Stargardt disease (STGD1), and related autosomal recessive retinopathies characterized by impaired central vision and an accumulation of lipofuscin and bis-retinoid compounds. High resolution structures of ABCA4 in its substrate and nucleotide free state and containing bound N-Ret-PE or ATP have been determined by cryo-electron microscopy providing insight into the molecular architecture of ABCA4 and mechanisms underlying substrate recognition and conformational changes induced by ATP binding. The expression and functional characterization of a large number of disease-causing missense ABCA4 variants have been determined. These studies have shed light into the molecular mechanisms underlying Stargardt disease and a classification that reliably predicts the effect of a specific missense mutation on the severity of the disease. They also provide a framework for developing rational therapeutic treatments for ABCA4-associated diseases.
Collapse
Affiliation(s)
- Robert S Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada; Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, B.C., Canada.
| | - Fabian A Garces
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | | | - Laurie L Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| |
Collapse
|
25
|
Schneider N, Sundaresan Y, Gopalakrishnan P, Beryozkin A, Hanany M, Levanon EY, Banin E, Ben-Aroya S, Sharon D. Inherited retinal diseases: Linking genes, disease-causing variants, and relevant therapeutic modalities. Prog Retin Eye Res 2021; 89:101029. [PMID: 34839010 DOI: 10.1016/j.preteyeres.2021.101029] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/11/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically complex and heterogenous group of visual impairment phenotypes caused by pathogenic variants in at least 277 nuclear and mitochondrial genes, affecting different retinal regions, and depleting the vision of affected individuals. Genes that cause IRDs when mutated are unique by possessing differing genotype-phenotype correlations, varying inheritance patterns, hypomorphic alleles, and modifier genes thus complicating genetic interpretation. Next-generation sequencing has greatly advanced the identification of novel IRD-related genes and pathogenic variants in the last decade. For this review, we performed an in-depth literature search which allowed for compilation of the Global Retinal Inherited Disease (GRID) dataset containing 4,798 discrete variants and 17,299 alleles published in 31 papers, showing a wide range of frequencies and complexities among the 194 genes reported in GRID, with 65% of pathogenic variants being unique to a single individual. A better understanding of IRD-related gene distribution, gene complexity, and variant types allow for improved genetic testing and therapies. Current genetic therapeutic methods are also quite diverse and rely on variant identification, and range from whole gene replacement to single nucleotide editing at the DNA or RNA levels. IRDs and their suitable therapies thus require a range of effective disease modelling in human cells, granting insight into disease mechanisms and testing of possible treatments. This review summarizes genetic and therapeutic modalities of IRDs, provides new analyses of IRD-related genes (GRID and complexity scores), and provides information to match genetic-based therapies such as gene-specific and variant-specific therapies to the appropriate individuals.
Collapse
Affiliation(s)
- Nina Schneider
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Yogapriya Sundaresan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Prakadeeswari Gopalakrishnan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Avigail Beryozkin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Mor Hanany
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Erez Y Levanon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Shay Ben-Aroya
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel.
| |
Collapse
|
26
|
Al-Khuzaei S, Broadgate S, Foster CR, Shah M, Yu J, Downes SM, Halford S. An Overview of the Genetics of ABCA4 Retinopathies, an Evolving Story. Genes (Basel) 2021; 12:1241. [PMID: 34440414 PMCID: PMC8392661 DOI: 10.3390/genes12081241] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 11/16/2022] Open
Abstract
Stargardt disease (STGD1) and ABCA4 retinopathies (ABCA4R) are caused by pathogenic variants in the ABCA4 gene inherited in an autosomal recessive manner. The gene encodes an importer flippase protein that prevents the build-up of vitamin A derivatives that are toxic to the RPE. Diagnosing ABCA4R is complex due to its phenotypic variability and the presence of other inherited retinal dystrophy phenocopies. ABCA4 is a large gene, comprising 50 exons; to date > 2000 variants have been described. These include missense, nonsense, splicing, structural, and deep intronic variants. Missense variants account for the majority of variants in ABCA4. However, in a significant proportion of patients with an ABCA4R phenotype, a second variant in ABCA4 is not identified. This could be due to the presence of yet unknown variants, or hypomorphic alleles being incorrectly classified as benign, or the possibility that the disease is caused by a variant in another gene. This underlines the importance of accurate genetic testing. The pathogenicity of novel variants can be predicted using in silico programs, but these rely on databases that are not ethnically diverse, thus highlighting the need for studies in differing populations. Functional studies in vitro are useful towards assessing protein function but do not directly measure the flippase activity. Obtaining an accurate molecular diagnosis is becoming increasingly more important as targeted therapeutic options become available; these include pharmacological, gene-based, and cell replacement-based therapies. The aim of this review is to provide an update on the current status of genotyping in ABCA4 and the status of the therapeutic approaches being investigated.
Collapse
Affiliation(s)
- Saoud Al-Khuzaei
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | | | - Mital Shah
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
| | - Jing Yu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Susan M. Downes
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| |
Collapse
|
27
|
Duzkale N, Arslan U. Investigation of genotype-phenotype relationship in Turkish patients with inherited retinal disease by next generation sequencing. Ophthalmic Genet 2021; 42:674-684. [PMID: 34315337 DOI: 10.1080/13816810.2021.1952616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Inherited retinal dystrophies (IRDs) are a group of retinal diseases genetically and clinically highly heterogeneous and associated with more than 300 genes. This study aims to investigate the genetic basis of Turkish patients with IRDs. MATERIALS AND METHODS In the study, genes related to retinal diseases in 86 IRDs patients were analyzed using the Next Generations Sequencing method (NGS). RESULTS The mean age of 86 patients was 35 and the mean age at diagnosis was 18. There was consanguinity between the parents of 62% of these patients. Fifty-six retinal disease-associated genes of 46 patients and 230 retinal disease-associated genes of 40 patients were examined. Genetic analysis provides a molecular diagnosis in a total of 53 (61.6%) patients. The genes responsible for the IRDs phenotype were frequently identified as ABCA4 (25%), EYS (11%), and RDH12 (9%). There was no significant difference between those with and without a molecular diagnosis in terms of demographic characteristics and family history. CONCLUSIONS Determination of genetic cause by NGS method in IRDs subgroups that are difficult to define by ophthalmic examination ensures that patients receive accurate diagnosis, treatment and counseling. This study contributed to the understanding of the genotype-phenotype relationship of Turkish patients with IRDs.
Collapse
Affiliation(s)
- Neslihan Duzkale
- Department of Medical Genetic, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Umut Arslan
- Department of Bioretina, Ankara University Technopolis, Ankara, Turkey
| |
Collapse
|
28
|
Jaffal L, Joumaa H, Mrad Z, Zeitz C, Audo I, El Shamieh S. The genetics of rod-cone dystrophy in Arab countries: a systematic review. Eur J Hum Genet 2021; 29:897-910. [PMID: 33188265 PMCID: PMC8187393 DOI: 10.1038/s41431-020-00754-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/02/2020] [Accepted: 10/20/2020] [Indexed: 02/07/2023] Open
Abstract
Since a substantial difference in the prevalence of genetic causes of rod-cone dystrophy (RCD) was found among different populations, we conducted a systematic review of the genetic findings associated with RCD in Arab countries. Of the 816 articles retrieved from PubMed, 31 studies conducted on 407 participants from 11 countries were reviewed. Next-generation sequencing (NGS) was the most commonly used technique (68%). Autosomal recessive pattern was the most common pattern of inheritance (97%) and half of the known genes associated with RCD (32/63) were identified. In the Kingdom of Saudi Arabia, in addition to RP1 (20%) and TULP1 (20%), gene defects in EYS (8%) and CRB1 (7%) were also prevalently mutated. In North Africa, the main gene defects were in MERTK (18%) and RLBP1 (18%). Considering all countries, RP1 and TULP1 remained the most prevalently mutated. Variants in TULP1, RP1, EYS, MERTK, and RLBP1 were the most prevalent, possibly because of founder effects. On the other hand, only ten Individuals were found to have dominant or X-linked RCD. This is the first time a catalog of RCD genetic variations has been established in subjects from the Arabi countries. Although the last decade has seen significant interest, expertise, and an increase in RCD scientific publication, much work needs to be conducted.
Collapse
Affiliation(s)
- Lama Jaffal
- Department of Biological and Environmental Sciences, Faculty of Science, Beirut Arab University, Debbieh, 1107 2809, Lebanon
- Rammal Hassan Rammal Research Laboratory, Physiotoxicity (PhyTox), Faculty of Sciences, Lebanese University, Nabatieh, 1700, Lebanon
| | - Hawraa Joumaa
- Rammal Hassan Rammal Research Laboratory, Physiotoxicity (PhyTox), Faculty of Sciences, Lebanese University, Nabatieh, 1700, Lebanon
| | - Zamzam Mrad
- Rammal Hassan Rammal Research Laboratory, Physiotoxicity (PhyTox), Faculty of Sciences, Lebanese University, Nabatieh, 1700, Lebanon
| | - Christina Zeitz
- Sorbonne Universités, INSERM, CNRS, Institut de la Vision, Paris, 75012, France
| | - Isabelle Audo
- Sorbonne Universités, INSERM, CNRS, Institut de la Vision, Paris, 75012, France
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC1423, 28 rue de Charenton, F-75012, Paris, France
- University College London Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Said El Shamieh
- Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, 1107 2809, Lebanon.
| |
Collapse
|
29
|
Absence of Genotype/Phenotype Correlations Requires Molecular Diagnostic to Ascertain Stargardt and Stargardt-Like Swiss Patients. Genes (Basel) 2021; 12:genes12060812. [PMID: 34073554 PMCID: PMC8229718 DOI: 10.3390/genes12060812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
We genetically characterized 22 Swiss patients who had been diagnosed with Stargardt disease after clinical examination. We identified in 11 patients (50%) pathogenic bi-allelic ABCA4 variants, c.1760+2T>C and c.4496T>C being novel. The dominantly inherited pathogenic ELOVL4 c.810C>G p.(Tyr270*) and PRPH2-c.422A>G p.(Tyr141Cys) variants were identified in eight (36%) and three patients (14%), respectively. All patients harboring the ELOVL4 c.810C>G p.(Tyr270*) variant originated from the same small Swiss area, identifying a founder mutation. In the ABCA4 and ELOVL4 cohorts, the clinical phenotypes of “flecks”, “atrophy”, and “bull’s eye like” were observed by fundus examination. In the small number of patients harboring the pathogenic PRPH2 variant, we could observe both “flecks” and “atrophy” clinical phenotypes. The onset of disease, progression of visual acuity and clinical symptoms, inheritance patterns, fundus autofluorescence, and optical coherence tomography did not allow discrimination between the genetically heterogeneous Stargardt patients. The genetic heterogeneity observed in the relatively small Swiss population should prompt systematic genetic testing of clinically diagnosed Stargardt patients. The resulting molecular diagnostic is required to prevent potentially harmful vitamin A supplementation, to provide genetic counseling with respect to inheritance, and to schedule appropriate follow-up visits in the presence of increased risk of choroidal neovascularization.
Collapse
|
30
|
Cowan CS, Renner M, De Gennaro M, Gross-Scherf B, Goldblum D, Hou Y, Munz M, Rodrigues TM, Krol J, Szikra T, Cuttat R, Waldt A, Papasaikas P, Diggelmann R, Patino-Alvarez CP, Galliker P, Spirig SE, Pavlinic D, Gerber-Hollbach N, Schuierer S, Srdanovic A, Balogh M, Panero R, Kusnyerik A, Szabo A, Stadler MB, Orgül S, Picelli S, Hasler PW, Hierlemann A, Scholl HPN, Roma G, Nigsch F, Roska B. Cell Types of the Human Retina and Its Organoids at Single-Cell Resolution. Cell 2021; 182:1623-1640.e34. [PMID: 32946783 PMCID: PMC7505495 DOI: 10.1016/j.cell.2020.08.013] [Citation(s) in RCA: 309] [Impact Index Per Article: 103.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 06/14/2020] [Accepted: 08/06/2020] [Indexed: 01/05/2023]
Abstract
Human organoids recapitulating the cell-type diversity and function of their target organ are valuable for basic and translational research. We developed light-sensitive human retinal organoids with multiple nuclear and synaptic layers and functional synapses. We sequenced the RNA of 285,441 single cells from these organoids at seven developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable "developed" state at a rate similar to human retina development in vivo. Transcriptomes of organoid cell types converged toward the transcriptomes of adult peripheral retinal cell types. Expression of disease-associated genes was cell-type-specific in adult retina, and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in human retinas.
Collapse
Affiliation(s)
- Cameron S Cowan
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Magdalena Renner
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Martina De Gennaro
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Brigitte Gross-Scherf
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - David Goldblum
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Yanyan Hou
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Martin Munz
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Tiago M Rodrigues
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Jacek Krol
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Tamas Szikra
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Rachel Cuttat
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Annick Waldt
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Panagiotis Papasaikas
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Roland Diggelmann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, 4058 Basel, Switzerland
| | - Claudia P Patino-Alvarez
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Patricia Galliker
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Stefan E Spirig
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Dinko Pavlinic
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | | | - Sven Schuierer
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Aldin Srdanovic
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Marton Balogh
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Riccardo Panero
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Akos Kusnyerik
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Arnold Szabo
- Department of Anatomy, Histology and Embryology, Semmelweis University, 1085 Budapest, Hungary
| | - Michael B Stadler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Selim Orgül
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Simone Picelli
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Pascal W Hasler
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Andreas Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, 4058 Basel, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland; Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Guglielmo Roma
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Florian Nigsch
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Botond Roska
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland.
| |
Collapse
|
31
|
de-Pablo-Cabrera A, Muñoz-Gallego A, Tejada-Palacios P. Contribution of Optical Coherence Tomography to the Diagnosis of Childhood-Onset Stargardt Disease in Its Early Stages. J Pediatr Ophthalmol Strabismus 2021; 58:e5-e8. [PMID: 34039161 DOI: 10.3928/01913913-20210205-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stargardt disease may present with alterations in optical coherence tomography before symptoms and fundus abnormalities appear. With this non-invasive test, a presumptive diagnosis can be made and genetically confirmed in the subclinical stages of the disease. [J Pediatr Ophthalmol Strabismus. 2021;58(3):e5-e8.].
Collapse
|
32
|
Camp DA, Gemayel MC, Ciulla TA. Understanding the genetic pathology of Stargardt disease: a review of current findings and challenges. Expert Opin Orphan Drugs 2021. [DOI: 10.1080/21678707.2021.1898373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- David A. Camp
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Michael C. Gemayel
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Thomas A. Ciulla
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
- Retina Service, Midwest Eye Institute, Indianapolis, IN, USA
| |
Collapse
|
33
|
Mena MD, Moresco AA, Vidal SH, Aguilar-Cortes D, Obregon MG, Fandiño AC, Sendoya JM, Llera AS, Podhajcer OL. Clinical and Genetic Spectrum of Stargardt Disease in Argentinean Patients. Front Genet 2021; 12:646058. [PMID: 33841504 PMCID: PMC8033171 DOI: 10.3389/fgene.2021.646058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/05/2021] [Indexed: 12/11/2022] Open
Abstract
Purpose To describe the clinical and molecular spectrum of Stargardt disease (STGD) in a cohort of Argentinean patients. Methods This retrospective study included 132 subjects comprising 95 probands clinically diagnosed with STGD and relatives from 16 of them. Targeted next-generation sequencing of the coding and splicing regions of ABCA4 and other phenocopying genes (ELOVL4, PROM1, and CNGB3) was performed in 97 STGD patients. Results We found two or more disease-causing variants in the ABCA4 gene in 69/95 (73%) probands, a single ABCA4 variant in 9/95 (9.5%) probands, and no ABCA4 variants in 17/95 (18%) probands. The final analysis identified 173 variants in ABCA4. Seventy-nine ABCA4 variants were unique, of which nine were novel. No significant findings were seen in the other evaluated genes. Conclusion This study describes the phenotypic and genetic features of STGD1 in an Argentinean cohort. The mutations p.(Gly1961Glu) and p.(Arg1129Leu) were the most frequent, representing almost 20% of the mutated alleles. We also expanded the ABCA4 mutational spectrum with nine novel disease-causing variants, of which eight might be associated with South American natives.
Collapse
Affiliation(s)
- Marcela D Mena
- Laboratorio de Terapia Molecular y Celular (Genocan), Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| | - Angélica A Moresco
- Servicio de Genética, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Buenos Aires, Argentina
| | - Sofía H Vidal
- Servicio de Oftalmología, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Buenos Aires, Argentina
| | - Diana Aguilar-Cortes
- Laboratorio de Terapia Molecular y Celular (Genocan), Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| | - María G Obregon
- Servicio de Genética, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Buenos Aires, Argentina
| | - Adriana C Fandiño
- Servicio de Oftalmología, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Buenos Aires, Argentina
| | - Juan M Sendoya
- Laboratorio de Terapia Molecular y Celular (Genocan), Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| | - Andrea S Llera
- Laboratorio de Terapia Molecular y Celular (Genocan), Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| | - Osvaldo L Podhajcer
- Laboratorio de Terapia Molecular y Celular (Genocan), Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina
| |
Collapse
|
34
|
Gatticchi L, Vešelényiová D, Miertus J, Enrico Maltese P, Manara E, Costantini A, Benedetti S, Ďurovčíková D, Krajcovic J, Bertelli M. Recessive multiple epiphyseal dysplasia and Stargardt disease in two sisters. Mol Genet Genomic Med 2021; 9:e1630. [PMID: 33724725 PMCID: PMC8123746 DOI: 10.1002/mgg3.1630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/22/2020] [Accepted: 02/12/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The rapid spread of genome-wide next-generation sequencing in the molecular diagnosis of rare genetic disorders has produced increasing evidence of multilocus genomic variations in cases with a previously well-characterized molecular diagnosis. Here, we describe two patients with a rare combination of skeletal abnormalities and retinal dystrophy caused by variants in the SLC26A2 and ABCA4 genes, respectively, in a family with parental consanguinity. METHODS Next-generation sequencing and Sanger sequencing were performed to obtain a molecular diagnosis for the retinal and skeletal phenotypes, respectively. RESULTS Genetic testing revealed that the sisters were homozygous for the p.(Cys653Ser) variant in SLC26A2 and heterozygous for the missense p.(Pro68Leu) and splice donor c.6386+2C>G variants in ABCA4. Segregation analysis confirmed the carrier status of the parents. CONCLUSION Despite low frequency of occurrence, the detection of multilocus genomic variations in a single disease gene-oriented approach can provide accurate diagnosis even in cases with high phenotypic complexity. A targeted sequencing approach can detect relationships between observed phenotypes and underlying genotypes, useful for clinical management.
Collapse
Affiliation(s)
- Leonardo Gatticchi
- Department of Experimental Medicine, Laboratory of Biochemistry, University of Perugia, Perugia, Italy
| | - Dominika Vešelényiová
- Department of Biology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Trnava, Slovakia
| | - Jan Miertus
- Génius n.o, Trnava, Slovakia.,MAGI's Lab, Genetic Testing Laboratory, Rovereto, Italy
| | | | | | | | | | - Darina Ďurovčíková
- Institute of Genetics and Molecular Medicine, Faculty of Medicine, Slovak Healthcare University, Bratislava, Slovakia
| | - Juraj Krajcovic
- Department of Biology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Trnava, Slovakia
| | - Matteo Bertelli
- MAGI's Lab, Genetic Testing Laboratory, Rovereto, Italy.,MAGI Euregio, Bolzano, Italy
| |
Collapse
|
35
|
Zhu Q, Rui X, Li Y, You Y, Sheng XL, Lei B. Identification of Four Novel Variants and Determination of Genotype-Phenotype Correlations for ABCA4 Variants Associated With Inherited Retinal Degenerations. Front Cell Dev Biol 2021; 9:634843. [PMID: 33732702 PMCID: PMC7957020 DOI: 10.3389/fcell.2021.634843] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/26/2021] [Indexed: 12/21/2022] Open
Abstract
Purpose The purpose of the study is to describe the genetic and clinical features of 17 patients with ABCA4-related inherited retinal degenerations (IRDs) and define the phenotype–genotype correlations. Methods In this multicenter retrospective study, 17 patients from 16 families were enrolled, and ABCA4 gene variants were detected using targeted next-generation sequencing using a custom designed panel for IRDs. Sanger sequencing and co-segregation analysis of the suspected pathogenic variants were performed with the family members. The pathogenicities of variants were evaluated according to the American College of Medical Genetics and Genomics guidelines (ACMG). Protein structure modifications mediated by the variants were studied using bioinformatic analyses. Results The probands were diagnosed with Stargardt disease 1 (7), cone-rod dystrophy type 3 (8), cone dystrophy (1), and retinitis pigmentosa 19 (1). Onset of symptoms occurred between 5 and 27 years of age (median age = 12.4 years). A total of 30 unique ABCA4 suspicious pathogenic variations were observed, including 18 missense mutations, seven frameshift mutations, two nonsense mutations, one canonical splice site mutation, one small in-frame deletion, and one insertion. Four novel ABCA4 variants were identified. Two novel frameshift variants, c.1290dupC (p.W431fs), and c.2967dupT (G990fs), were determined to be pathogenic. A novel missense variant c.G5761T (p.V1921L) was likely pathogenic, and another novel missense c.C170G (p.P57R) variant was of undetermined significance. All ABCA4 variants tested in this study inordinately changed the physico-chemical parameters and structure of protein based on in silico analysis. Conclusion ABCA4-related IRD is genetically and clinically highly heterogeneous. Four novel ABCA4 variants were identified. This study will expand the spectrum of disease-causing variants in ABCA4, which will further facilitate genetic counseling.
Collapse
Affiliation(s)
- Qing Zhu
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xue Rui
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, First Affiliated Hospital of Northwest University for Nationalities, Yinchuan, China
| | - Ya Li
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China.,Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute and Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ya You
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China.,Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute and Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xun-Lun Sheng
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, First Affiliated Hospital of Northwest University for Nationalities, Yinchuan, China
| | - Bo Lei
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China.,Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute and Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| |
Collapse
|
36
|
Liu F, Lee J, Chen J. Molecular structures of the eukaryotic retinal importer ABCA4. eLife 2021; 10:63524. [PMID: 33605212 PMCID: PMC7932691 DOI: 10.7554/elife.63524] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/18/2021] [Indexed: 12/20/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter family contains thousands of members with diverse functions. Movement of the substrate, powered by ATP hydrolysis, can be outward (export) or inward (import). ABCA4 is a eukaryotic importer transporting retinal to the cytosol to enter the visual cycle. It also removes toxic retinoids from the disc lumen. Mutations in ABCA4 cause impaired vision or blindness. Despite decades of clinical, biochemical, and animal model studies, the molecular mechanism of ABCA4 is unknown. Here, we report the structures of human ABCA4 in two conformations. In the absence of ATP, ABCA4 adopts an outward-facing conformation, poised to recruit substrate. The presence of ATP induces large conformational changes that could lead to substrate release. These structures provide a molecular basis to understand many disease-causing mutations and a rational guide for new experiments to uncover how ABCA4 recruits, flips, and releases retinoids.
Collapse
Affiliation(s)
- Fangyu Liu
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, United States.,Tri-Institutional Training Program in Chemical Biology, New York, United States
| | - James Lee
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, United States
| | - Jue Chen
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| |
Collapse
|
37
|
Maggi J, Koller S, Bähr L, Feil S, Kivrak Pfiffner F, Hanson JVM, Maspoli A, Gerth-Kahlert C, Berger W. Long-Range PCR-Based NGS Applications to Diagnose Mendelian Retinal Diseases. Int J Mol Sci 2021; 22:ijms22041508. [PMID: 33546218 PMCID: PMC7913364 DOI: 10.3390/ijms22041508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/27/2022] Open
Abstract
The purpose of this study was to develop a flexible, cost-efficient, next-generation sequencing (NGS) protocol for genetic testing. Long-range polymerase chain reaction (PCR) amplicons of up to 20 kb in size were designed to amplify entire genomic regions for a panel (n = 35) of inherited retinal disease (IRD)-associated loci. Amplicons were pooled and sequenced by NGS. The analysis was applied to 227 probands diagnosed with IRD: (A) 108 previously molecularly diagnosed, (B) 94 without previous genetic testing, and (C) 25 undiagnosed after whole-exome sequencing (WES). The method was validated with 100% sensitivity on cohort A. Long-range PCR-based sequencing revealed likely causative variant(s) in 51% and 24% of proband from cohorts B and C, respectively. Breakpoints of 3 copy number variants (CNVs) could be characterized. Long-range PCR libraries spike-in extended coverage of WES. Read phasing confirmed compound heterozygosity in 5 probands. The proposed sequencing protocol provided deep coverage of the entire gene, including intronic and promoter regions. Our method can be used (i) as a first-tier assay to reduce genetic testing costs, (ii) to elucidate missing heritability cases, (iii) to characterize breakpoints of CNVs at nucleotide resolution, (iv) to extend WES data to non-coding regions by spiking-in long-range PCR libraries, and (v) to help with phasing of candidate variants.
Collapse
Affiliation(s)
- Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Luzy Bähr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Fatma Kivrak Pfiffner
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - James V. M. Hanson
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, 8091 Zurich, Switzerland; (J.V.M.H.); (C.G.-K.)
| | - Alessandro Maspoli
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, 8091 Zurich, Switzerland; (J.V.M.H.); (C.G.-K.)
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8057 Zurich, Switzerland
- Correspondence: ; Tel.: +41-44-556-33-50
| |
Collapse
|
38
|
Perea-Romero I, Gordo G, Iancu IF, Del Pozo-Valero M, Almoguera B, Blanco-Kelly F, Carreño E, Jimenez-Rolando B, Lopez-Rodriguez R, Lorda-Sanchez I, Martin-Merida I, Pérez de Ayala L, Riveiro-Alvarez R, Rodriguez-Pinilla E, Tahsin-Swafiri S, Trujillo-Tiebas MJ, Garcia-Sandoval B, Minguez P, Avila-Fernandez A, Corton M, Ayuso C. Genetic landscape of 6089 inherited retinal dystrophies affected cases in Spain and their therapeutic and extended epidemiological implications. Sci Rep 2021; 11:1526. [PMID: 33452396 PMCID: PMC7810997 DOI: 10.1038/s41598-021-81093-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/31/2020] [Indexed: 02/08/2023] Open
Abstract
Inherited retinal diseases (IRDs), defined by dysfunction or progressive loss of photoreceptors, are disorders characterized by elevated heterogeneity, both at the clinical and genetic levels. Our main goal was to address the genetic landscape of IRD in the largest cohort of Spanish patients reported to date. A retrospective hospital-based cross-sectional study was carried out on 6089 IRD affected individuals (from 4403 unrelated families), referred for genetic testing from all the Spanish autonomous communities. Clinical, demographic and familiar data were collected from each patient, including family pedigree, age of appearance of visual symptoms, presence of any systemic findings and geographical origin. Genetic studies were performed to the 3951 families with available DNA using different molecular techniques. Overall, 53.2% (2100/3951) of the studied families were genetically characterized, and 1549 different likely causative variants in 142 genes were identified. The most common phenotype encountered is retinitis pigmentosa (RP) (55.6% of families, 2447/4403). The most recurrently mutated genes were PRPH2, ABCA4 and RS1 in autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) NON-RP cases, respectively; RHO, USH2A and RPGR in AD, AR and XL for non-syndromic RP; and USH2A and MYO7A in syndromic IRD. Pathogenic variants c.3386G > T (p.Arg1129Leu) in ABCA4 and c.2276G > T (p.Cys759Phe) in USH2A were the most frequent variants identified. Our study provides the general landscape for IRD in Spain, reporting the largest cohort ever presented. Our results have important implications for genetic diagnosis, counselling and new therapeutic strategies to both the Spanish population and other related populations.
Collapse
Affiliation(s)
- Irene Perea-Romero
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Gema Gordo
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Ionut F Iancu
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Del Pozo-Valero
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Berta Almoguera
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ester Carreño
- Department of Ophthalmology, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Belen Jimenez-Rolando
- Department of Ophthalmology, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Rosario Lopez-Rodriguez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Isabel Lorda-Sanchez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Inmaculada Martin-Merida
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Lucia Pérez de Ayala
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Rosa Riveiro-Alvarez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Elvira Rodriguez-Pinilla
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Saoud Tahsin-Swafiri
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Maria J Trujillo-Tiebas
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | | | | | | | - Blanca Garcia-Sandoval
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Department of Ophthalmology, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Pablo Minguez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Almudena Avila-Fernandez
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Corton
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain. .,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
| | - Carmen Ayuso
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain. .,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
| |
Collapse
|
39
|
Splicing mutations in inherited retinal diseases. Prog Retin Eye Res 2021. [DOI: 10.1016/j.preteyeres.2020.100874
expr 921883647 + 833887994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
|
40
|
Xu S, Coku A, Muraleedharan CK, Harajli A, Mishulin E, Dahabra C, Choi J, Garcia WJ, Webb K, Birch D, Goetz K, Li W. Mutation Screening in the miR-183/96/182 Cluster in Patients With Inherited Retinal Dystrophy. Front Cell Dev Biol 2020; 8:619641. [PMID: 33425925 PMCID: PMC7785829 DOI: 10.3389/fcell.2020.619641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/07/2020] [Indexed: 01/09/2023] Open
Abstract
Inherited retinal dystrophy (IRD) is a heterogenous blinding eye disease and affects more than 200,000 Americans and millions worldwide. By far, 270 protein-coding genes have been identified to cause IRD when defective. However, only one microRNA (miRNA), miR-204, has been reported to be responsible for IRD when a point-mutation occurs in its seed sequence. Previously, we identified that a conserved, polycistronic, paralogous miRNA cluster, the miR-183/96/182 cluster, is highly specifically expressed in all photoreceptors and other sensory organs; inactivation of this cluster in mice resulted in syndromic IRD with multi-sensory defects. We hypothesized that mutations in the miR-183/96/182 cluster in human cause IRD. To test this hypothesis, we perform mutation screening in the pre-miR-183, -96, -182 in >1000 peripheral blood DNA samples of patients with various forms of IRD. We identified six sequence variants, three in pre-miR-182 and three in pre-miR-96. These variants are in the pre-miRNA-182 or -96, but not in the mature miRNAs, and are unlikely to be the cause of the IRD in these patients. In spite of this, the nature and location of these sequence variants in the pre-miRNAs suggest that some may have impact on the biogenesis and maturation of miR-182 or miR-96 and potential roles in the susceptibility to diseases. Although reporting on negative results so far, our study established a system for mutation screening in the miR-183/96/182 cluster in human for a continued effort to unravel and provides deeper insight into the potential roles of miR-183/96/182 cluster in human diseases.
Collapse
Affiliation(s)
- Shunbin Xu
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ardian Coku
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Chithra K. Muraleedharan
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ali Harajli
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Eric Mishulin
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, United States
| | - Chafic Dahabra
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Joanne Choi
- Class of 2020, School of Medicine, Wayne State University, Detroit, MI, United States
| | - William J. Garcia
- College of Natural Science, Michigan State University, East Lansing, MI, United States
| | - Kaylie Webb
- Retina Foundation of the Southwest, Dallas, TX, United States
| | - David Birch
- Retina Foundation of the Southwest, Dallas, TX, United States
| | - Kerry Goetz
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Weifeng Li
- Peking Union Medical College, Beijing, China
| |
Collapse
|
41
|
Sun Z, Yang L, Li H, Zou X, Wang L, Wu S, Zhu T, Wei X, Zhong Y, Sui R. Clinical and genetic analysis of the ABCA4 gene associated retinal dystrophy in a large Chinese cohort. Exp Eye Res 2020; 202:108389. [PMID: 33301772 DOI: 10.1016/j.exer.2020.108389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 12/31/2022]
Abstract
ABCA4 gene associated retinal dystrophies (ABCA4-RD) are a group of inherited eye diseases caused by ABCA4 gene mutations, including Stargardt disease, cone-rod dystrophy and retinitis pigmentosa. With the development of next-generation sequencing (NGS), numerous clinical and genetic studies on ABCA4-RD have been performed, and the genotype and phenotype spectra have been elucidated. However, most of the studies focused on the Caucasian population and limited studies of large Chinese ABCA4-RD cohorts were reported. In this study, we summarized the phenotypic and genotypic characteristics of 129 Chinese patients with ABCA4-RD. We found a mutation spectrum of Chinese patients which is considerably different from that of the Caucasian population and identified 35 novel ABCA4 mutations. We also reported some rare and special cases, such as, pedigrees with patients in two generations, patients diagnosed with cone-rod dystrophy or retinitis pigmentosa, patients with subretinal fibrosis and patients with preserved foveal structure. At the same time, we focused on the correlation between the genotypes and phenotypes. By the comprehensive analysis of multiple clinical examinations and the application of multiple regression analysis, we proved that patients with two "null" variants had a younger onset age and reached legal blindness earlier than patients with two "none-null" variants. Patients with one or more "none-null" variants tended to have better visual acuity and presented with milder fundus autofluorescence changes and more preserved rod functions on the full-field electroretinography than patients with two "null" variants. Furthermore, most patients with the p.(Phe2188Ser) variant shared a mild phenotype with a low fundus autofluorescence signal limited to the fovea and with normal full-field electroretinography responses. Our findings expand the variant spectrum of the ABCA4 gene and enhance the knowledge of Chinese patients with ABCA4-RD.
Collapse
Affiliation(s)
- Zixi Sun
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Lizhu Yang
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization, Tokyo Medical Center, Tokyo, 152-8902, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Hui Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Xuan Zou
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Lei Wang
- Beijing Mei'ermu Hospital, Beijing, China
| | - Shijing Wu
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Tian Zhu
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Xing Wei
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Yong Zhong
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China.
| | - Ruifang Sui
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China.
| |
Collapse
|
42
|
Kubota R, Birch DG, Gregory JK, Koester JM. Randomised study evaluating the pharmacodynamics of emixustat hydrochloride in subjects with macular atrophy secondary to Stargardt disease. Br J Ophthalmol 2020; 106:403-408. [PMID: 33214244 PMCID: PMC8867285 DOI: 10.1136/bjophthalmol-2020-317712] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/26/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022]
Abstract
Background/Aims Stargardt disease is a rare, inherited, degenerative disease of the retina that is the most common type of hereditary macular dystrophy. Currently, no approved treatments for the disease exist. The purpose of this study was to characterise the pharmacodynamics of emixustat, an orally available small molecule that targets the retinal pigment epithelium–specific 65 kDa protein (RPE65), in subjects with macular atrophy secondary to Stargardt disease. Methods In this multicentre study conducted at six study sites in the USA, 23 subjects with macular atrophy secondary to Stargardt disease were randomised to one of three doses of daily emixustat (2.5 mg, 5 mg or 10 mg) and treated for 1 month. The primary outcome was the suppression of the rod b-wave recovery rate on electroretinography after photobleaching, which is an indirect measure of RPE65 inhibition. Results Subjects who received 10 mg emixustat showed near-complete suppression of the rod b-wave amplitude recovery rate postphotobleaching (mean=91.86%, median=96.69%), whereas those who received 5 mg showed moderate suppression (mean=52.2%, median=68.0%). No effect was observed for subjects who received 2.5 mg emixustat (mean=−3.31%, median=−12.23%). The adverse event profile was consistent with prior studies in other patient populations and consisted primarily of ocular adverse events likely related to RPE65 inhibition. Conclusion This study demonstrated dose-dependent suppression of rod b-wave amplitude recovery postphotobleaching, confirming emixustat’s biological activity in patients with Stargardt disease. These findings informed dose selection for a 24-month phase 3 trial (SeaSTAR Study) that is now comparing emixustat to placebo in the treatment of Stargardt disease-associated macular atrophy.
Collapse
Affiliation(s)
- Ryo Kubota
- President, Kubota Vision Inc, Seattle, Washington, USA
| | - David G Birch
- Scientific Director, Retina Foundation of the Southwest, Dallas, Texas, USA
| | - Jeff K Gregory
- Clinical Development, Kubota Vision Inc, Seattle, Washington, USA
| | - John M Koester
- Clinical Development, Kubota Vision Inc, Seattle, Washington, USA
| |
Collapse
|
43
|
Whole exome sequencing and homozygosity mapping reveals genetic defects in consanguineous Iranian families with inherited retinal dystrophies. Sci Rep 2020; 10:19413. [PMID: 33173045 PMCID: PMC7655865 DOI: 10.1038/s41598-020-75841-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/08/2020] [Indexed: 12/17/2022] Open
Abstract
Inherited retinal dystrophies (IRDs), displaying pronounced genetic and clinical heterogeneity, comprise of a broad range of diseases characterized by progressive retinal cell death and gradual loss of vision. By the combined use of whole exome sequencing (WES), SNP-array and WES-based homozygosity mapping, as well as directed DNA sequencing (Sanger), we have identified nine pathogenic variants in six genes (ABCA4, RPE65, MERTK, USH2A, SPATA7, TULP1) in 10 consanguineous Iranian families. Six of the nine identified variants were novel, including a putative founder mutation in ABCA4 (c.3260A>G, p.Glu1087Gly), detected in two families from Northeastern Iran. Our findings provide additional information to the molecular pathology of IRDs in Iran, hopefully contributing to better genetic counselling and patient management in the respective families from this country.
Collapse
|
44
|
Hu FY, Gao FJ, Li JK, Xu P, Wang DD, Zhang SH, Wu JH. Novel variants of ABCA4 in Han Chinese families with Stargardt disease. BMC MEDICAL GENETICS 2020; 21:213. [PMID: 33129279 PMCID: PMC7602306 DOI: 10.1186/s12881-020-01152-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Stargardt disease (STGD1) is a common recessive hereditary macular dystrophy in early adulthood or childhood, with an estimated prevalence of 1:8000 to 1:10,000. ABCA4 is the causative gene for STGD1. The current study aims at identifying the novel disease-related ABCA4 variants in Han Chinese families with STGD1 using next-generation sequencing (NGS). METHODS In the present study, 12 unrelated Han Chinese families (19 males and 17 females) with STGD1 were tested by panel-based NGS. In order to capture the coding exons and the untranslated regions (UTRs) plus 30 bp of intronic flanking sequences of 792 genes, which were closely associated with usual ophthalmic genetic disease, we designed a customized panel, namely, Target_Eye_792_V2 chip. STGD1 patients were clinically diagnosed by experienced ophthalmologists. All the detected variants were filtered and analyzed through the public databases and in silico programs to assess potential pathogenicity. RESULTS Twenty-one ABCA4 mutant variants were detected in 12 unrelated Han Chinese families with STGD1, containing 14 missense, three splicing, two frameshift, one small deletion, and one nonsense variants. Base on the American College of Medical Genetics (ACMG) guidelines, 8 likely pathogenic and 13 pathogenic variants were determined. The functional consequences of these mutant variants were predicted through in silico programs. Of the 21 mutant variants in ABCA4, two novel coding variants c.3017G > A and c.5167 T > C and one novel null variant c.3051-1G > A were detected in three unrelated probands. CONCLUSIONS By panel-based NGS, 21 ABCA4 variants were confirmed in 12 unrelated Han Chinese families. Among them, 3 novel mutant variants were found, which further expanded the ABCA4 mutation spectrum in STGD1 patients.
Collapse
Affiliation(s)
- Fang-Yuan Hu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Feng-Juan Gao
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jian-Kang Li
- BGI-Shenzhen, Shenzhen, China
- Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong
| | - Ping Xu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Dan-Dan Wang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Sheng-Hai Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Ji-Hong Wu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.
| |
Collapse
|
45
|
Collison FT, Lee W, Fishman GA, Park JC, Zernant J, McAnany JJ, Allikmets R. CLINICAL CHARACTERIZATION OF STARGARDT DISEASE PATIENTS WITH THE p.N1868I ABCA4 MUTATION. Retina 2020; 39:2311-2325. [PMID: 30204727 DOI: 10.1097/iae.0000000000002316] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the Stargardt disease phenotype associated with an unusually common and "extremely hypomorphic" ABCA4 variant, p.N1868I. METHODS The charts of 27 patients with p.N1868I on one allele and a severe/deleterious mutation on the other allele were reviewed. Subjective age of onset, best-corrected visual acuity, and stage of disease were recorded for all 27 patients, 18 of whom had multiple visits. When available, fundus photography, spectral domain optical coherence tomography, fundus autofluorescence, full-field electroretinograms, Goldmann visual fields, and fluorescein angiography were included. Five families with multiple affected members were analyzed. RESULTS The median age at symptom onset was 41.5 years, and 3 p.N1868I patients had not developed visual symptoms as of the most recent eye examination. Median best-corrected visual acuity in the better-seeing eye at baseline was 20/25, and the median duration from symptom onset to legal blindness was 25 years. The five families described in this study demonstrated clinically significant intrafamilial variability, and affected family members who did not share the p.N1868I variant had relatively more severe phenotypes. CONCLUSION This study demonstrates the consistency of foveal sparing, the variation in age at onset, the intrafamilial variability, and the prognosis with regard to visual acuity in p.N1868I-associated Stargardt disease.
Collapse
Affiliation(s)
- Frederick T Collison
- The Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, Illinois
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, New York
| | - Gerald A Fishman
- The Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, Illinois.,Department of Ophthalmology and Visual Sciences, The University of Illinois at Chicago, Chicago, Illinois
| | - Jason C Park
- Department of Ophthalmology and Visual Sciences, The University of Illinois at Chicago, Chicago, Illinois
| | - Jana Zernant
- Department of Ophthalmology, Columbia University, New York, New York
| | - J Jason McAnany
- Department of Ophthalmology and Visual Sciences, The University of Illinois at Chicago, Chicago, Illinois
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, New York.,Department of Pathology and Cell Biology, Columbia University, New York, New York
| |
Collapse
|
46
|
Curtis SB, Molday LL, Garces FA, Molday RS. Functional analysis and classification of homozygous and hypomorphic ABCA4 variants associated with Stargardt macular degeneration. Hum Mutat 2020; 41:1944-1956. [PMID: 32845050 DOI: 10.1002/humu.24100] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/06/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022]
Abstract
Stargardt macular degeneration (Stargardt disease 1 [STGD1]) is caused by mutations in the gene encoding ABCA4, an ATP-binding cassette protein that transports N-retinylidene-phosphatidylethanolamine (N-Ret-PE) across photoreceptor membranes. Reduced ABCA4 activity results in retinoid accumulation leading to photoreceptor degeneration. The disease onset and severity vary from severe loss in visual acuity in the first decade to mild visual impairment late in life. We determined the effect of 22 disease-causing missense mutations on the expression and ATPase activity of ABCA4 in the absence and presence of N-Ret-PE. Three classes were identified that correlated with the disease onset in homozygous STGD1 individuals: Class 1 exhibited reduced ABCA4 expression and ATPase activity that was not stimulated by N-Ret-PE; individuals homozygous for these variants had an early disease onset (≤13 years); Class 2 showed reduced ATPase activity with limited stimulation by N-Ret-PE; these correlated with moderate disease onset (14-40 years); and Class 3 displayed high expression and ATPase activity that was strongly activated by N-Ret-PE; these were associated with late disease onset (>40 years). On the basis of our results, we introduce a functionality index for gauging the effect of missense mutations on STGD1 severity. Our studies support the mild phenotype exhibited by the p.Gly863Ala, p.Asn1868Ile, and p.Gly863Ala/p.Asn1868Ile variants.
Collapse
Affiliation(s)
- Susan B Curtis
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fabian A Garces
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
47
|
Novel variants associated with Stargardt disease in Chinese patients. Gene 2020; 754:144890. [DOI: 10.1016/j.gene.2020.144890] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 12/11/2022]
|
48
|
Splicing mutations in inherited retinal diseases. Prog Retin Eye Res 2020; 80:100874. [PMID: 32553897 DOI: 10.1016/j.preteyeres.2020.100874] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 05/30/2020] [Accepted: 05/31/2020] [Indexed: 12/15/2022]
Abstract
Mutations which induce aberrant transcript splicing represent a distinct class of disease-causing genetic variants in retinal disease genes. Such mutations may either weaken or erase regular splice sites or create novel splice sites which alter exon recognition. While mutations affecting the canonical GU-AG dinucleotides at the splice donor and splice acceptor site are highly predictive to cause a splicing defect, other variants in the vicinity of the canonical splice sites or those affecting additional cis-acting regulatory sequences within exons or introns are much more difficult to assess or even to recognize and require additional experimental validation. Splicing mutations are unique in that the actual outcome for the transcript (e.g. exon skipping, pseudoexon inclusion, intron retention) and the encoded protein can be quite different depending on the individual mutation. In this article, we present an overview on the current knowledge about and impact of splicing mutations in inherited retinal diseases. We introduce the most common sub-classes of splicing mutations including examples from our own work and others and discuss current strategies for the identification and validation of splicing mutations, as well as therapeutic approaches, open questions, and future perspectives in this field of research.
Collapse
|
49
|
Molecular Analysis of the ABCA4 Gene Mutations in Patients with Stargardt Disease Using Human Hair Follicles. Int J Mol Sci 2020; 21:ijms21103430. [PMID: 32413971 PMCID: PMC7279462 DOI: 10.3390/ijms21103430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/05/2020] [Accepted: 05/10/2020] [Indexed: 12/17/2022] Open
Abstract
ABCA4 gene mutations are the cause of a spectrum of ABCA4 retinopathies, and the most common juvenile macular degeneration is called Stargardt disease. ABCA4 has previously been observed almost exclusively in the retina. Therefore, studying the functional consequences of ABCA4 variants has required advanced molecular analysis techniques. The aim of the present study was to evaluate whether human hair follicles may be used for molecular analysis of the ABCA4 gene splice-site variants in patients with ABCA4 retinopathies. We assessed ABCA4 expression in hair follicles and skin at mRNA and protein levels by means of real-time PCR and Western blot analyses, respectively. We performed cDNA sequencing to reveal the presence of full-length ABCA4 transcripts and analyzed ABCA4 transcripts from three patients with Stargardt disease carrying different splice-site ABCA4 variants: c.5312+1G>A, c.5312+2T>G and c.5836-3C>A. cDNA analysis revealed that c.5312+1G>A, c.5312+2T>G variants led to the skipping of exon 37, and the c.5836-3C>A variant resulted in the insertion of 30 nucleotides into the transcript. Our results strongly argue for the use of hair follicles as a model for the molecular analysis of the pathogenicity of ABCA4 variants in patients with ABCA4 retinopathies.
Collapse
|
50
|
Application of CRISPR Tools for Variant Interpretation and Disease Modeling in Inherited Retinal Dystrophies. Genes (Basel) 2020; 11:genes11050473. [PMID: 32349249 PMCID: PMC7290804 DOI: 10.3390/genes11050473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022] Open
Abstract
Inherited retinal dystrophies are an assorted group of rare diseases that collectively account for the major cause of visual impairment of genetic origin worldwide. Besides clinically, these vision loss disorders present a high genetic and allelic heterogeneity. To date, over 250 genes have been associated to retinal dystrophies with reported causative variants of every nature (nonsense, missense, frameshift, splice-site, large rearrangements, and so forth). Except for a fistful of mutations, most of them are private and affect one or few families, making it a challenge to ratify the newly identified candidate genes or the pathogenicity of dubious variants in disease-associated loci. A recurrent option involves altering the gene in in vitro or in vivo systems to contrast the resulting phenotype and molecular imprint. To validate specific mutations, the process must rely on simulating the precise genetic change, which, until recently, proved to be a difficult endeavor. The rise of the CRISPR/Cas9 technology and its adaptation for genetic engineering now offers a resourceful suite of tools to alleviate the process of functional studies. Here we review the implementation of these RNA-programmable Cas9 nucleases in culture-based and animal models to elucidate the role of novel genes and variants in retinal dystrophies.
Collapse
|