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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 2024:2817278. [PMID: 38602673 PMCID: PMC11009866 DOI: 10.1001/jamaophthalmol.2024.0660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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.
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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
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Corradi Z, Khan M, Hitti-Malin R, Mishra K, Whelan L, Cornelis SS, Hoyng CB, Kämpjärvi K, Klaver CCW, Liskova P, Stöhr H, Weber BHF, Banfi S, Farrar GJ, Sharon D, Zernant J, Allikmets R, Dhaenens CM, Cremers FPM. Targeted sequencing and in vitro splice assays shed light on ABCA4-associated retinopathies missing heritability. HGG Adv 2023; 4:100237. [PMID: 37705246 PMCID: PMC10534262 DOI: 10.1016/j.xhgg.2023.100237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023] Open
Abstract
The ABCA4 gene is the most frequently mutated Mendelian retinopathy-associated gene. Biallelic variants lead to a variety of phenotypes, however, for thousands of cases the underlying variants remain unknown. Here, we aim to shed further light on the missing heritability of ABCA4-associated retinopathy by analyzing a large cohort of macular dystrophy probands. A total of 858 probands were collected from 26 centers, of whom 722 carried no or one pathogenic ABCA4 variant, while 136 cases carried two ABCA4 alleles, one of which was a frequent mild variant, suggesting that deep-intronic variants (DIVs) or other cis-modifiers might have been missed. After single molecule molecular inversion probes (smMIPs)-based sequencing of the complete 128-kb ABCA4 locus, the effect of putative splice variants was assessed in vitro by midigene splice assays in HEK293T cells. The breakpoints of copy number variants (CNVs) were determined by junction PCR and Sanger sequencing. ABCA4 sequence analysis solved 207 of 520 (39.8%) naive or unsolved cases and 70 of 202 (34.7%) monoallelic cases, while additional causal variants were identified in 54 of 136 (39.7%) probands carrying two variants. Seven novel DIVs and six novel non-canonical splice site variants were detected in a total of 35 alleles and characterized, including the c.6283-321C>G variant leading to a complex splicing defect. Additionally, four novel CNVs were identified and characterized in five alleles. These results confirm that smMIPs-based sequencing of the complete ABCA4 gene provides a cost-effective method to genetically solve retinopathy cases and that several rare structural and splice altering defects remain undiscovered in Stargardt disease cases.
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Affiliation(s)
- 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
| | - Rebekkah Hitti-Malin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ketan Mishra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Laura Whelan
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Stéphanie S Cornelis
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Caroline C W Klaver
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands; Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands; Institute of Molecular & Clinical Ophthalmology, Basel, Switzerland
| | - Petra Liskova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic; Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Heidi Stöhr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany; Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
| | - Sandro Banfi
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli," Naples and Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - G Jane Farrar
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jana Zernant
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY, USA; Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands; University Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, 59000 Lille, France
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
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3
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Cornelis SS, Runhart EH, Bauwens M, Corradi Z, De Baere E, Roosing S, Haer-Wigman L, Dhaenens CM, Vulto-van Silfhout AT, Cremers FP. Personalized genetic counseling for Stargardt disease: Offspring risk estimates based on variant severity. Am J Hum Genet 2022; 109:498-507. [PMID: 35120629 DOI: 10.1016/j.ajhg.2022.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/11/2022] [Indexed: 12/21/2022] Open
Abstract
Recurrence risk calculations in autosomal recessive diseases are complicated when the effect of genetic variants and their population frequencies and penetrances are unknown. An example of this is Stargardt disease (STGD1), a frequent recessive retinal disease caused by bi-allelic pathogenic variants in ABCA4. In this cross-sectional study, 1,619 ABCA4 variants from 5,579 individuals with STGD1 were collected and categorized by (1) severity based on statistical comparisons of their frequencies in STGD1-affected individuals versus the general population, (2) their observed versus expected homozygous occurrence in STGD1-affected individuals, (3) their occurrence in combination with established mild alleles in STGD1-affected individuals, and (4) previous functional and clinical studies. We used the sum allele frequencies of these severity categories to estimate recurrence risks for offspring of STGD1-affected individuals and carriers of pathogenic ABCA4 variants. The risk for offspring of an STGD1-affected individual with the "severe|severe" genotype or a "severe|mild with complete penetrance" genotype to develop STGD1 at some moment in life was estimated at 2.8%-3.1% (1 in 36-32 individuals) and 1.6%-1.8% (1 in 62-57 individuals), respectively. The risk to develop STGD1 in childhood was estimated to be 2- to 4-fold lower: 0.68%-0.79% (1 in 148-126) and 0.34%-0.39% (1 in 296-252), respectively. In conclusion, we established personalized recurrence risk calculations for STGD1-affected individuals with different combinations of variants. We thus propose an expanded genotype-based personalized counseling to appreciate the variable recurrence risks for STGD1-affected individuals. This represents a conceptual breakthrough because risk calculations for STGD1 may be exemplary for many other inherited diseases.
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4
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Runhart EH, Khan M, Cornelis SS, Roosing S, Del Pozo-Valero M, Lamey TM, Liskova P, Roberts L, Stöhr H, Klaver CCW, Hoyng CB, Cremers FPM, Dhaenens CM. Association of Sex With Frequent and Mild ABCA4 Alleles in Stargardt Disease. JAMA Ophthalmol 2021; 138:1035-1042. [PMID: 32815999 DOI: 10.1001/jamaophthalmol.2020.2990] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Importance The mechanisms behind the phenotypic variability and reduced penetrance in autosomal recessive Stargardt disease (STGD1), often a blinding disease, are poorly understood. Identification of the unknown disease modifiers can improve patient and family counseling and provide valuable information for disease management. Objective To assess the association of incompletely penetrant ABCA4 alleles with sex in STGD1. Design, Setting, and Participants Genetic data for this cross-sectional study were obtained from 2 multicenter genetic studies of 1162 patients with clinically suspected STGD1. Unrelated patients with genetically confirmed STGD1 were selected. The data were collected from June 2016 to June 2019, and post hoc analysis was performed between July 2019 and January 2020. Main Outcomes and Measures Penetrance of reported mild ABCA4 variants was calculated by comparing the allele frequencies in the general population (obtained from the Genome Aggregation Database) with the genotyping data in the patient population (obtained from the ABCA4 Leiden Open Variation Database). The sex ratio among patients with and patients without an ABCA4 allele with incomplete penetrance was assessed. Results A total of 550 patients were included in the study, among which the mean (SD) age was 45.7 (18.0) years and most patients were women (311 [57%]). Five of the 5 mild ABCA4 alleles, including c.5603A>T and c.5882G>A, were calculated to have incomplete penetrance. The women to men ratio in the subgroup carrying c.5603A>T was 1.7 to 1; the proportion of women in this group was higher compared with the subgroup not carrying a mild allele (difference, 13%; 95% CI, 3%-23%; P = .02). The women to men ratio in the c.5882G>A subgroup was 2.1 to 1, and the women were overrepresented compared with the group carrying no mild allele (difference, 18%; 95% CI, 6%-30%; P = .005). Conclusions and Relevance This study found an imbalance in observed sex ratio among patients harboring a mild ABCA4 allele, which concerns approximately 25% of all patients with STGD1, suggesting that STGD1 should be considered a polygenic or multifactorial disease rather than a disease caused by ABCA4 gene mutations alone. The findings suggest that sex should be considered as a potential disease-modifying variable in both basic research and clinical trials on STGD1.
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Affiliation(s)
- Esmee H Runhart
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mubeen Khan
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Stéphanie S Cornelis
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susanne Roosing
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marta Del Pozo-Valero
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Petra Liskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Lisa Roberts
- University of Cape Town/MRC Genomic and Precision Medicine Research Unit, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Heidi Stöhr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Caroline C W Klaver
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P M Cremers
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,University Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
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5
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Runhart EH, Valkenburg D, Cornelis SS, Khan M, Sangermano R, Albert S, Bax NM, Astuti GDN, Gilissen C, Pott JWR, Verheij JBGM, Blokland EAW, Cremers FPM, van den Born LI, Hoyng CB. Late-Onset Stargardt Disease Due to Mild, Deep-Intronic ABCA4 Alleles. Invest Ophthalmol Vis Sci 2020; 60:4249-4256. [PMID: 31618761 DOI: 10.1167/iovs.19-27524] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the role of two deep-intronic ABCA4 variants, that showed a mild splice defect in vitro and can occur on the same allele as the low penetrant c.5603A>T, in Stargardt disease (STGD1). Methods Ophthalmic data were assessed of 18 STGD1 patients who harbored c.769-784C>T or c.4253+43G>A in combination with a severe ABCA4 variant. Subjects carrying c.[769-784C>T; 5603A>T] were clinically compared with a STGD1 cohort previously published carrying c.5603A>T noncomplex. We calculated the penetrances of the intronic variants using ABCA4 allele frequency data of the general population and investigated the effect of c.769-784C>T on splicing in photoreceptor progenitor cells (PPCs). Results Mostly, late-onset, foveal-sparing STGD1 was observed among subjects harboring c.769-784C>T or c.4253+43G>A (median age of onset, 54.5 and 52.0 years, respectively). However, ages of onset, phenotypes in fundo, and visual acuity courses varied widely. No significant clinical differences were observed between the c.[769-784C>T; 5603A>T] cohort and the c.4253+43G>A or the c.5603A>T cohort. The penetrances of c.769-784C>T (20.5%-39.6%) and c.4253+43G>A (35.8%-43.1%) were reduced, when not considering the effect of yet unidentified or known factors in cis, such as c.5603A>T (identified in 7/7 probands with c.769-784C>T; 1/8 probands with c.4253+43G>A). Variant c.769-784C>T resulted in a pseudo-exon insertion in 15% of the total mRNA (i.e., ∼30% of the c.769-784C>T allele alone). Conclusions Two mild intronic ABCA4 variants could further explain missing heritability in late-onset STGD1, distinguishing it from AMD. The observed clinical variability and calculated reduced penetrance urge research into modifiers within and outside of the ABCA4 gene.
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Affiliation(s)
- Esmee H Runhart
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dyon Valkenburg
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stéphanie S Cornelis
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mubeen Khan
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Riccardo Sangermano
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Silvia Albert
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nathalie M Bax
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Galuh D N Astuti
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Division of Human Genetics, Center for Biomedical Research, Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Christian Gilissen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jan-Willem R Pott
- Department of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Joke B G M Verheij
- Department of Medical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ellen A W Blokland
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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6
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Fadaie Z, Khan M, Del Pozo‐Valero M, Cornelis SS, Ayuso C, Cremers FPM, Roosing S, The ABCA4 study group. Identification of splice defects due to noncanonical splice site or deep-intronic variants in ABCA4. Hum Mutat 2019; 40:2365-2376. [PMID: 31397521 PMCID: PMC6899986 DOI: 10.1002/humu.23890] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/30/2019] [Accepted: 08/04/2019] [Indexed: 12/25/2022]
Abstract
Pathogenic variants in the ATP-binding cassette transporter A4 (ABCA4) gene cause a continuum of retinal disease phenotypes, including Stargardt disease. Noncanonical splice site (NCSS) and deep-intronic variants constitute a large fraction of disease-causing alleles, defining the functional consequences of which remains a challenge. We aimed to determine the effect on splicing of nine previously reported or unpublished NCSS variants, one near exon splice variant and nine deep-intronic variants in ABCA4, using in vitro splice assays in human embryonic kidney 293T cells. Reverse transcription-polymerase chain reaction and Sanger sequence analysis revealed splicing defects for 12 out of 19 variants. Four deep-intronic variants create pseudoexons or elongate the upstream exon. Furthermore, eight NCSS variants cause a partial deletion or skipping of one or more exons in messenger RNAs. Among the 12 variants, nine lead to premature stop codons and predicted truncated ABCA4 proteins. At least two deep-intronic variants affect splice enhancer and silencer motifs and, therefore, these conserved sequences should be carefully evaluated when predicting the outcome of NCSS and deep-intronic variants.
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Affiliation(s)
- Zeinab Fadaie
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Marta Del Pozo‐Valero
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
- Department of Genetics, Instituto de Investigación Sanitaria–Fundación Jiménez Díaz University HospitalUniversidad Autónoma de Madrid (IIS‐FJD, UAM)MadridSpain
| | - Stéphanie S. Cornelis
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Carmen Ayuso
- Department of Genetics, Instituto de Investigación Sanitaria–Fundación Jiménez Díaz University HospitalUniversidad Autónoma de Madrid (IIS‐FJD, UAM)MadridSpain
| | - Frans P. M. Cremers
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
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7
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Khan M, Cornelis SS, Khan MI, Elmelik D, Manders E, Bakker S, Derks R, Neveling K, van de Vorst M, Gilissen C, Meunier I, Defoort S, Puech B, Devos A, Schulz HL, Stöhr H, Grassmann F, Weber BHF, Dhaenens CM, Cremers FPM. Cost-effective molecular inversion probe-based ABCA4 sequencing reveals deep-intronic variants in Stargardt disease. Hum Mutat 2019; 40:1749-1759. [PMID: 31212395 DOI: 10.1002/humu.23787] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/18/2019] [Accepted: 04/29/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE Stargardt disease (STGD1) is caused by biallelic mutations in ABCA4, but many patients are genetically unsolved due to insensitive mutation-scanning methods. We aimed to develop a cost-effective sequencing method for ABCA4 exons and regions carrying known causal deep-intronic variants. METHODS Fifty exons and 12 regions containing 14 deep-intronic variants of ABCA4 were sequenced using double-tiled single molecule Molecular Inversion Probe (smMIP)-based next-generation sequencing. DNAs of 16 STGD1 cases carrying 29 ABCA4 alleles and of four healthy persons were sequenced using 483 smMIPs. Thereafter, DNAs of 411 STGD1 cases with one or no ABCA4 variant were sequenced. The effect of novel noncoding variants on splicing was analyzed using in vitro splice assays. RESULTS Thirty-four ABCA4 variants previously identified in 16 STGD1 cases were reliably identified. In 155/411 probands (38%), two causal variants were identified. We identified 11 deep-intronic variants present in 62 alleles. Two known and two new noncanonical splice site variants showed splice defects, and one novel deep-intronic variant (c.4539+2065C>G) resulted in a 170-nt mRNA pseudoexon insertion (p.[Arg1514Lysfs*35,=]). CONCLUSIONS smMIPs-based sequence analysis of coding and selected noncoding regions of ABCA4 enabled cost-effective mutation detection in STGD1 cases in previously unsolved cases.
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Affiliation(s)
- Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stéphanie S Cornelis
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Duaa Elmelik
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eline Manders
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sem Bakker
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maartje van de Vorst
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Isabelle Meunier
- Institut des Neurosciences de Montpellier, INSERM, Université de Montpellier, Montpellier, France
| | - Sabine Defoort
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | - Bernard Puech
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | - Aurore Devos
- University of Lille, INSERM UMR-S1172, CHU Lille, Biochemistry and Molecular Biology Department, UF Genopathies, Lille, France
| | - Heidi L Schulz
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Heidi Stöhr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Felix Grassmann
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany.,Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Claire-Marie Dhaenens
- University of Lille, INSERM UMR-S1172, CHU Lille, Biochemistry and Molecular Biology Department, UF Genopathies, Lille, France
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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8
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Cremers FPM, Cornelis SS, Runhart EH, Astuti GDN. Author Response: Penetrance of the ABCA4 p.Asn1868Ile Allele in Stargardt Disease. Invest Ophthalmol Vis Sci 2019; 59:5566-5568. [PMID: 30480704 DOI: 10.1167/iovs.18-25944] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stéphanie S Cornelis
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Esmee H Runhart
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Galuh D N Astuti
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Division of Human Genetics, Center for Biomedical Research, Faculty of Medicine, Diponegoro University, Semarang, Indonesia
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9
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Runhart EH, Sangermano R, Cornelis SS, Verheij JBGM, Plomp AS, Boon CJF, Lugtenberg D, Roosing S, Bax NM, Blokland EAW, Jacobs-Camps MHM, van der Velde-Visser SD, Pott JWR, Rohrschneider K, Thiadens AAHJ, Klaver CCW, van den Born LI, Hoyng CB, Cremers FPM. The Common ABCA4 Variant p.Asn1868Ile Shows Nonpenetrance and Variable Expression of Stargardt Disease When Present in trans With Severe Variants. Invest Ophthalmol Vis Sci 2019; 59:3220-3231. [PMID: 29971439 DOI: 10.1167/iovs.18-23881] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To assess the occurrence and the disease expression of the common p.Asn1868Ile variant in patients with Stargardt disease (STGD1) harboring known, monoallelic causal ABCA4 variants. Methods The coding and noncoding regions of ABCA4 were sequenced in 67 and 63 STGD1 probands respectively, harboring monoallelic ABCA4 variants. In case p.Asn1868Ile was detected, segregation analysis was performed whenever possible. Probands and affected siblings harboring p.Asn1868Ile without additional variants in cis were clinically evaluated retrospectively. Two asymptomatic siblings carrying the same ABCA4 variants as their probands were clinically examined. The penetrance of p.Asn1868Ile was calculated using allele frequency data of ABCA4 variants in non-Finnish European individuals. Results The p.Asn1868Ile variant was found in cis with known variants in 14/67 probands. In 27/67 probands, we identified p.Asn1868Ile without additional variants in cis, in combination with known, mainly severe ABCA4 variants. In 23/27 probands, the trans configuration was established. Among 27 probands and 6/7 STGD1 siblings carrying p.Asn1868Ile, 42% manifested late-onset disease (>44 years). We additionally identified four asymptomatic relatives carrying a combination of a severe variant and p.Asn1868Ile; ophthalmologic examination in two persons did not reveal STGD1. Based on ABCA4 allele frequency data, we conservatively estimated the penetrance of p.Asn1868Ile, when present in trans with a severe variant, to be below 5%. Conclusions A significant fraction of genetically unexplained STGD1 cases carries p.Asn1868Ile as a second variant. Our findings suggest exceptional differences in disease expression or even nonpenetrance of this ABCA4 variant, pointing toward an important role for genetic or environmental modifiers in STGD1.
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Affiliation(s)
- Esmee H Runhart
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Riccardo Sangermano
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stéphanie S Cornelis
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joke B G M Verheij
- Department of Medical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Astrid S Plomp
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Academic Medical Center, Amsterdam, The Netherlands
| | - Dorien Lugtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Roosing
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nathalie M Bax
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ellen A W Blokland
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Jan-Willem R Pott
- Department of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Klaus Rohrschneider
- Universitätsaugenklinik, Ruprecht-Karls-Universität, Heidelberg, Heidelberg, Germany
| | - Alberta A H J Thiadens
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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10
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Abstract
Inherited retinal diseases (IRDs) display a very high degree of clinical and genetic heterogeneity, which poses challenges in finding the underlying defects in known IRD-associated genes and in identifying novel IRD-associated genes. Knowledge on the molecular and clinical aspects of IRDs has increased tremendously in the last decade. Here, we outline the state-of-the-art techniques to find the causative genetic variants, with special attention for next-generation sequencing which can combine molecular diagnostics and retinal disease gene identification. An important aspect is the functional assessment of rare variants with RNA and protein effects which can only be predicted in silico. We therefore describe the in vitro assessment of putative splice defects in human embryonic kidney cells. In addition, we outline the use of stem cell technology to generate photoreceptor precursor cells from patients' somatic cells which can subsequently be used for RNA and protein studies. Finally, we outline the in silico methods to interpret the causality of variants associated with inherited retinal disease and the registry of these variants.
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Affiliation(s)
- Mubeen Khan
- Department of Human Genetics, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Zeinab Fadaie
- Department of Human Genetics, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stéphanie S Cornelis
- Department of Human Genetics, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
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11
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Sangermano R, Khan M, Cornelis SS, Richelle V, Albert S, Garanto A, Elmelik D, Qamar R, Lugtenberg D, van den Born LI, Collin RWJ, Cremers FPM. ABCA4 midigenes reveal the full splice spectrum of all reported noncanonical splice site variants in Stargardt disease. Genome Res 2018. [PMID: 29162642 DOI: 10.1101/gr.226621.117/-/dc1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Stargardt disease is caused by variants in the ABCA4 gene, a significant part of which are noncanonical splice site (NCSS) variants. In case a gene of interest is not expressed in available somatic cells, small genomic fragments carrying potential disease-associated variants are tested for splice abnormalities using in vitro splice assays. We recently discovered that when using small minigenes lacking the proper genomic context, in vitro results do not correlate with splice defects observed in patient cells. We therefore devised a novel strategy in which a bacterial artificial chromosome was employed to generate midigenes, splice vectors of varying lengths (up to 11.7 kb) covering almost the entire ABCA4 gene. These midigenes were used to analyze the effect of all 44 reported and three novel NCSS variants on ABCA4 pre-mRNA splicing. Intriguingly, multi-exon skipping events were observed, as well as exon elongation and intron retention. The analysis of all reported NCSS variants in ABCA4 allowed us to reveal the nature of aberrant splicing events and to classify the severity of these mutations based on the residual fraction of wild-type mRNA. Our strategy to generate large overlapping splice vectors carrying multiple exons, creating a toolbox for robust and high-throughput analysis of splice variants, can be applied to all human genes.
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Affiliation(s)
- Riccardo Sangermano
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Mubeen Khan
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.,Department of Biosciences, COMSATS Institute of Information Technology, Islamabad 45550, Pakistan
| | - Stéphanie S Cornelis
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Valerie Richelle
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Silvia Albert
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Alejandro Garanto
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Duaa Elmelik
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Raheel Qamar
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad 45550, Pakistan
| | - Dorien Lugtenberg
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - L Ingeborgh van den Born
- The Rotterdam Eye Hospital, 3011 BH Rotterdam, The Netherlands.,The Rotterdam Ophthalmic Institute, 3011 BH Rotterdam, The Netherlands
| | - Rob W J Collin
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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12
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Cornelis SS, Bax NM, Zernant J, Allikmets R, Fritsche LG, den Dunnen JT, Ajmal M, Hoyng CB, Cremers FPM. In Silico Functional Meta-Analysis of 5,962 ABCA4 Variants in 3,928 Retinal Dystrophy Cases. Hum Mutat 2017; 38:400-408. [PMID: 28044389 DOI: 10.1002/humu.23165] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/20/2016] [Accepted: 12/27/2016] [Indexed: 12/26/2022]
Abstract
Variants in the ABCA4 gene are associated with a spectrum of inherited retinal diseases (IRDs), most prominently with autosomal recessive (ar) Stargardt disease (STGD1) and ar cone-rod dystrophy. The clinical outcome to a large degree depends on the severity of the variants. To provide an accurate prognosis and to select patients for novel treatments, functional significance assessment of nontruncating ABCA4 variants is important. We collected all published ABCA4 variants from 3,928 retinal dystrophy cases in a Leiden Open Variation Database, and compared their frequency in 3,270 Caucasian IRD cases with 33,370 non-Finnish European control individuals. Next to the presence of 270 protein-truncating variants, 191 nontruncating variants were significantly enriched in the patient cohort. Furthermore, 30 variants were deemed benign. Assessing the homozygous occurrence of frequent variants in IRD cases based on the allele frequencies in control individuals confirmed the mild nature of the p.[Gly863Ala, Gly863del] variant and identified three additional mild variants (p.(Ala1038Val), c.5714+5G>A, and p.(Arg2030Gln)). The p.(Gly1961Glu) variant was predicted to act as a mild variant in most cases. Based on these data, in silico analyses, and American College of Medical Genetics and Genomics guidelines, we provide pathogenicity classifications on a five-tier scale from benign to pathogenic for all variants in the ABCA4-LOVD database.
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Affiliation(s)
- Stéphanie S Cornelis
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nathalie M Bax
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Jana Zernant
- Department of Ophthalmology, Columbia University, New York, New York
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, New York.,Department of Pathology & Cell Biology, Columbia University, New York, New York
| | - Lars G Fritsche
- Department of Public Health, K.G. Jebsen Center for Genetic Epidemiology, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | - Johan T den Dunnen
- Departments of Clinical Genetics and Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Muhammad Ajmal
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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