1
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Wang J, Wang Y, Jiang Y, Li S, Jia X, Xiao X, Sun W, Wang P, Zhang Q. Datasets-Based IMPDH1 Revisited: Heterozygous Missense Variants for Dominant Retinitis Pigmentosa While Truncation Variants Are Likely Non-Pathogenic. Curr Eye Res 2024; 49:853-861. [PMID: 38604988 DOI: 10.1080/02713683.2024.2336158] [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: 04/19/2023] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
PURPOSE Heterozygous variants of IMPDH1 are associated with autosomal dominant retinitis pigmentosa (adRP). The current study aims to investigate the characteristics of the adRP-associated variants. METHODS IMPDH1 variants from our exome sequencing dataset were retrieved and systemically evaluated through multiple online prediction tools, comparative genomics (in-house dataset, HGMD, and gnomAD), and phenotypic association. Potential pathogenic variants (PPVs) were further confirmed by Sanger sequencing and segregation analysis. RESULTS In total, seven heterozygous PPVs (six missenses and one inframe) were identified in 10 families with RP, in which six of the seven might be classified as pathogenic or likely pathogenic while one others as variants of uncertain significance. IMPDH1 variants contributed to 0.7% (10/1519) of RP families in our cohort, ranking the top four genes implicated in adRP. These adRP-associated variants were located in exons 8-10, a region within or downstream of the CBS domain. All these variants were predicted to be damaged by at least three of the six online prediction tools. Two truncation variants were considered non-pathogenic. Hitherto, 41 heterozygous variants of IMPDH1 were detected in 110 families in published literature, including 33 missenses, two inframes, and six truncations (including a synonymous variant affecting splicing). Of the 35 missense and inframe variants, most were clustered in exons 8-10 (77.1%, 27/35), including 18 (51.4%, 18/35) in exon 10 accounting for 70.9% (78/110) of the families. However, truncation variants were enriched in the general population with a pLI value of 0 (tolerated), and the reported variants in patients with RP did not cluster in specific region. CONCLUSIONS Our data together with comprehensive analysis of existing datasets suggest that causative variants of IMPDH1 are usually missense and mostly clustered in exons 8-10. Conversely, most missense variants outside this region and truncation variants should be interpreted with great care in clinical gene test.
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Affiliation(s)
- Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Department of Ophthalmology, The Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, Enshi, Hubei, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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2
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Wright CF, Sharp LN, Jackson L, Murray A, Ware JS, MacArthur DG, Rehm HL, Patel KA, Weedon MN. Guidance for estimating penetrance of monogenic disease-causing variants in population cohorts. Nat Genet 2024:10.1038/s41588-024-01842-3. [PMID: 39075210 DOI: 10.1038/s41588-024-01842-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 06/24/2024] [Indexed: 07/31/2024]
Abstract
Penetrance is the probability that an individual with a pathogenic genetic variant develops a specific disease. Knowing the penetrance of variants for monogenic disorders is important for counseling of individuals. Until recently, estimates of penetrance have largely relied on affected individuals and their at-risk family members being clinically referred for genetic testing, a 'phenotype-first' approach. This approach substantially overestimates the penetrance of variants because of ascertainment bias. The recent availability of whole-genome sequencing data in individuals from very-large-scale population-based cohorts now allows 'genotype-first' estimates of penetrance for many conditions. Although this type of population-based study can underestimate penetrance owing to recruitment biases, it provides more accurate estimates of penetrance for secondary or incidental findings. Here, we provide guidance for the conduct of penetrance studies to ensure that robust genotypes and phenotypes are used to accurately estimate penetrance of variants and groups of similarly annotated variants from population-based studies.
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Affiliation(s)
- Caroline F Wright
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK.
| | - Luke N Sharp
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK
| | - Leigh Jackson
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK
| | - Anna Murray
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK
| | - James S Ware
- National Heart and Lung Institute and MRC Laboratory of Medical Sciences, Imperial College London, London, UK
- Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
- Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Daniel G MacArthur
- Centre for Population Genomics, Garvan Institute of Medical Research and UNSW Sydney, Sydney, New South Wales, Australia
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Heidi L Rehm
- Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Kashyap A Patel
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK
| | - Michael N Weedon
- Department of Clinical and Biomedical Sciences, Medical School, University of Exeter, Exeter, UK.
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3
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Murro V, Banfi S, Testa F, Iarossi G, Falsini B, Sodi A, Signorini S, Iolascon A, Russo R, Mucciolo DP, Caputo R, Bacci GM, Bargiacchi S, Turco S, Fortini S, Simonelli F. A multidisciplinary approach to inherited retinal dystrophies from diagnosis to initial care: a narrative review with inputs from clinical practice. Orphanet J Rare Dis 2023; 18:223. [PMID: 37525225 PMCID: PMC10388566 DOI: 10.1186/s13023-023-02798-z] [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: 10/10/2022] [Accepted: 07/05/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND Non-syndromic inherited retinal dystrophies (IRDs) such as retinitis pigmentosa or Leber congenital amaurosis generally manifest between early childhood and late adolescence, imposing profound long-term impacts as a result of vision impairment or blindness. IRDs are highly heterogeneous, with often overlapping symptoms among different IRDs, and achieving a definite diagnosis is challenging. This narrative review provides a clinical overview of the non-syndromic generalized photoreceptor dystrophies, particularly retinitis pigmentosa and Leber congenital amaurosis. The clinical investigations and genetic testing needed to establish a diagnosis are outlined, and current management approaches are discussed, focusing on the importance of the involvement of an interdisciplinary team from diagnosis and initial care to long-term follow-up and support. RESULTS The effective management of IRDs requires a multidisciplinary, and ideally interdisciplinary, team of experts knowledgeable about IRDs, with experienced professionals from fields as diverse as ophthalmology, neuropsychiatry, psychology, neurology, genetics, orthoptics, developmental therapy, typhlology, occupational therapy, otolaryngology, and orientation and mobility specialties. Accurate clinical diagnosis encompasses a range of objective and subjective assessments as a prerequisite for the genetic testing essential in establishing an accurate diagnosis necessary for the effective management of IRDs, particularly in the era of gene therapies. Improvements in genome sequencing techniques, such as next-generation sequencing, have greatly facilitated the complex process of determining IRD-causing gene variants and establishing a molecular diagnosis. Genetic counseling is essential to help the individual and their family understand the condition, the potential risk for offspring, and the implications of a diagnosis on visual prognosis and treatment options. Psychological support for patients and caregivers is important at all stages of diagnosis, care, and rehabilitation and is an essential part of the multidisciplinary approach to managing IRDs. Effective communication throughout is essential, and the patient and caregivers' needs and expectations must be acknowledged and discussed. CONCLUSION As IRDs can present at an early age, clinicians need to be aware of the clinical signs suggesting visual impairment and follow up with multidisciplinary support for timely diagnoses to facilitate appropriate therapeutic or rehabilitation intervention to minimize vision loss.
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Affiliation(s)
- Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
- Eye Clinic, Careggi Teaching Hospital, Florence, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, NA, Italy
- Medical Genetics, Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy.
| | - Giancarlo Iarossi
- Department of Ophthalmology, Bambino Gesù Children's Hospital, Rome, Italy
| | - Benedetto Falsini
- Ophthalmology Unit, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Andrea Sodi
- Eye Clinic, Careggi Teaching Hospital, Florence, Italy
| | - Sabrina Signorini
- Center of Child Neuro-Ophthalmology, IRCCS, Mondino Foundation, Pavia, Italy
| | - Achille Iolascon
- Medical Genetics Unit, Azienda Ospedaliera Universitaria Federico II, Naples, Italy
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
- CEINGE-Biotecnologie Avanzate, Naples, Italy
| | - Roberta Russo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
- CEINGE-Biotecnologie Avanzate, Naples, Italy
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
- Ophthalmology Unit, San Jacopo Hospital, Pistoia, Italy
| | - Roberto Caputo
- Pediatric Ophthalmology Unit, A. Meyer Children's Hospital IRCCS, Florence, Italy
| | - Giacomo Maria Bacci
- Pediatric Ophthalmology Unit, A. Meyer Children's Hospital IRCCS, Florence, Italy
| | - Sara Bargiacchi
- Medical Genetics Unit, Ospedale Pediatrico Meyer, Florence, Italy
| | - Simona Turco
- National Centre of Services and Research for the Prevention of Blindness and Rehabilitation of the Visually Impaired, International Agency for the Prevention of Blindness-IAPB Italy Onlus, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Stefania Fortini
- National Centre of Services and Research for the Prevention of Blindness and Rehabilitation of the Visually Impaired, International Agency for the Prevention of Blindness-IAPB Italy Onlus, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
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4
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Variant Landscape of 15 Genes Involved in Corneal Dystrophies: Report of 30 Families and Comprehensive Analysis of the Literature. Int J Mol Sci 2023; 24:ijms24055012. [PMID: 36902444 PMCID: PMC10003302 DOI: 10.3390/ijms24055012] [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: 12/26/2022] [Revised: 02/27/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Corneal dystrophies (CDs) represent a group of inherited diseases characterized by the progressive deposit of abnormal materials in the cornea. This study aimed to describe the variant landscape of 15 genes responsible for CDs based on a cohort of Chinese families and a comparative analysis of literature reports. Families with CDs were recruited from our eye clinic. Their genomic DNA was analyzed using exome sequencing. The detected variants were filtered using multi-step bioinformatics and confirmed using Sanger sequencing. Previously reported variants in the literature were summarized and evaluated based on the gnomAD database and in-house exome data. In 30 of 37 families with CDs, 17 pathogenic or likely pathogenic variants were detected in 4 of the 15 genes, including TGFBI, CHST6, SLC4A11, and ZEB1. A comparative analysis of large datasets revealed that 12 of the 586 reported variants are unlikely causative of CDs in monogenic mode, accounting for 61 of 2933 families in the literature. Of the 15 genes, the gene most frequently implicated in CDs was TGFBI (1823/2902, 62.82% of families), followed by CHST6 (483/2902, 16.64%) and SLC4A11 (201/2902, 6.93%). This study presents, for the first time, the landscape of pathogenic and likely pathogenic variants in the 15 genes responsible for CDs. Awareness of frequently misinterpreted variants, such as c.1501C>A, p.(Pro501Thr) in TGFBI, is crucial in the era of genomic medicine.
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5
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Masson E, Zou WB, Génin E, Cooper DN, Le Gac G, Fichou Y, Pu N, Rebours V, Férec C, Liao Z, Chen JM. Expanding ACMG variant classification guidelines into a general framework. Hum Genomics 2022; 16:31. [PMID: 35974416 PMCID: PMC9380380 DOI: 10.1186/s40246-022-00407-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The American College of Medical Genetics and Genomics (ACMG)-recommended five variant classification categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign) have been widely used in medical genetics. However, these guidelines are fundamentally constrained in practice owing to their focus upon Mendelian disease genes and their dichotomous classification of variants as being either causal or not. Herein, we attempt to expand the ACMG guidelines into a general variant classification framework that takes into account not only the continuum of clinical phenotypes, but also the continuum of the variants' genetic effects, and the different pathological roles of the implicated genes. MAIN BODY As a disease model, we employed chronic pancreatitis (CP), which manifests clinically as a spectrum from monogenic to multifactorial. Bearing in mind that any general conceptual proposal should be based upon sound data, we focused our analysis on the four most extensively studied CP genes, PRSS1, CFTR, SPINK1 and CTRC. Based upon several cross-gene and cross-variant comparisons, we first assigned the different genes to two distinct categories in terms of disease causation: CP-causing (PRSS1 and SPINK1) and CP-predisposing (CFTR and CTRC). We then employed two new classificatory categories, "predisposing" and "likely predisposing", to replace ACMG's "pathogenic" and "likely pathogenic" categories in the context of CP-predisposing genes, thereby classifying all pathologically relevant variants in these genes as "predisposing". In the case of CP-causing genes, the two new classificatory categories served to extend the five ACMG categories whilst two thresholds (allele frequency and functional) were introduced to discriminate "pathogenic" from "predisposing" variants. CONCLUSION Employing CP as a disease model, we expand ACMG guidelines into a five-category classification system (predisposing, likely predisposing, uncertain significance, likely benign, and benign) and a seven-category classification system (pathogenic, likely pathogenic, predisposing, likely predisposing, uncertain significance, likely benign, and benign) in the context of disease-predisposing and disease-causing genes, respectively. Taken together, the two systems constitute a general variant classification framework that, in principle, should span the entire spectrum of variants in any disease-related gene. The maximal compliance of our five-category and seven-category classification systems with the ACMG guidelines ought to facilitate their practical application.
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Affiliation(s)
- Emmanuelle Masson
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France.,Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | - Wen-Bin Zou
- Department of Gastroenterology, Changhai Hospital, The Secondary Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Emmanuelle Génin
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Gerald Le Gac
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France.,Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France
| | - Na Pu
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France.,Department of Critical Care Medicine, Research Institute of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Vinciane Rebours
- Department of Gastroenterology and Pancreatology, Beaujon Hospital, Assistance Publique-Hôpitaux de Paris, Clichy, Université de Paris, Paris, France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France
| | - Zhuan Liao
- Department of Gastroenterology, Changhai Hospital, The Secondary Military Medical University, Shanghai, China.,Shanghai Institute of Pancreatic Diseases, Shanghai, China
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, 22 Avenue Camille Desmoulins, F-29200, Brest, France.
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6
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Martin-Gutierrez MP, Schiff ER, Wright G, Waseem N, Mahroo OA, Michaelides M, Moore AT, Webster AR, Arno G. Dominant Cone Rod Dystrophy, Previously Assigned to a Missense Variant in RIMS1, Is Fully Explained by Co-Inheritance of a Dominant Allele of PROM1. Invest Ophthalmol Vis Sci 2022; 63:14. [PMID: 35947379 PMCID: PMC9381847 DOI: 10.1167/iovs.63.9.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 05/04/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose Autosomal dominant cone rod dystrophy 7 (CORD7) was initially linked to the gene RIMS1 and reported in a 4-generation British family in 1998. The purpose of this study was to investigate the legitimacy of this association, and to correctly characterize the genetic cause of this condition. Methods The allele frequency of RIMS1 c.2459G>A, p.Arg820His, was investigated in the Genomes Aggregation Dataset (gnomAD) datasets and whole genome sequencing (WGS) was performed for 4 members of the CORD7 family with filtering of rare pathogenic variants in a virtual gene panel comprising all genes known to be associated with inherited retinal dystrophy (IRD). Cytogenetic analysis was performed to rule out interchromosomal translocation. Results RIMS1 p.Arg820His has a maximal carrier frequency of >1:5000 in Europeans. A previously well-characterized PROM1 variant: c.1118C>T, p.Arg373Cys, was detected in 9 affected members of the CORD7 family who underwent WGS or direct sequencing. One affected family member is now known to have macular dystrophy in the absence of RIMS1 p.Arg820His. Clinical analysis of affected family members and 27 individuals with retinopathy associated with the same - PROM1 - variant showed consistent phenotypes. Conclusions The case for pathogenicity of RIMS1 p.Arg820His is not strong based on its presence on 10 alleles in the gnomAD dataset and absence from additional CORD affected individuals. The finding of a known pathogenic variant in PROM1 correlates well with the phenotypic characteristics of the affected individuals, and is likely to account for the condition. Clear evidence of association between RIMS1 and a retinal dystrophy is yet to be described.
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Affiliation(s)
| | - Elena R. Schiff
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Genevieve Wright
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | | | - Omar A. Mahroo
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Anthony T. Moore
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Andrew R. Webster
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Gavin Arno
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - for the Genomics England Research Consortium
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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7
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Tanner A, Chan HW, Schiff E, Mahroo OM, Pulido JS. Exploring the mutational landscape of genes associated with inherited retinal disease using large genomic datasets: identifying loss of function intolerance and outlying propensities for missense changes. BMJ Open Ophthalmol 2022; 7:bmjophth-2022-001079. [PMID: 36161854 PMCID: PMC9422814 DOI: 10.1136/bmjophth-2022-001079] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/18/2022] [Indexed: 11/11/2022] Open
Abstract
Background Large databases permit quantitative description of genes in terms of intolerance to loss of function (‘haploinsufficiency’) and prevalence of missense variants. We explored these parameters in inherited retinal disease (IRD) genes. Methods IRD genes (from the ‘RetNet’ resource) were classified by probability of loss of function intolerance (pLI) using online Genome Aggregation Database (gnomAD) and DatabasE of genomiC varIation and Phenotype in Humans using Ensembl Resources (DECIPHER) databases. Genes were identified having pLI ≥0.9 together with one or both of the following: upper bound of CI <0.35 for observed to expected (o/e) ratio of loss of function variants in the gnomAD resource; haploinsufficiency score <10 in the DECIPHER resource. IRD genes in which missense variants appeared under-represented or over-represented (Z score for o/e ratio of <−2.99 or >2.99, respectively) were also identified. The genes were evaluated in the gene ontology Protein Analysis THrough Evolutionary Relationships (PANTHER) resource. Results Of 280 analysed genes, 39 (13.9%) were predicted loss of function intolerant. A greater proportion of X-linked than autosomal IRD genes fulfilled these criteria, as expected. Most autosomal genes were associated with dominant disease. PANTHER analysis showed >100 fold enrichment of spliceosome tri-snRNP complex assembly. Most encoded proteins were longer than the median length in the UniProt database. Fourteen genes (11 of which were in the ‘haploinsufficient’ group) showed under-representation of missense variants. Six genes (SAMD11, ALMS1, WFS1, RP1L1, KCNV2, ADAMTS18) showed over-representation of missense variants. Conclusion A minority of IRD-associated genes appear to be ‘haploinsufficient’. Over-representation of spliceosome pathways was observed. When interpreting genetic tests, variants found in genes with over-representation of missense variants should be interpreted with caution.
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8
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Kingdom R, Wright CF. Incomplete Penetrance and Variable Expressivity: From Clinical Studies to Population Cohorts. Front Genet 2022; 13:920390. [PMID: 35983412 PMCID: PMC9380816 DOI: 10.3389/fgene.2022.920390] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 12/20/2022] Open
Abstract
The same genetic variant found in different individuals can cause a range of diverse phenotypes, from no discernible clinical phenotype to severe disease, even among related individuals. Such variants can be said to display incomplete penetrance, a binary phenomenon where the genotype either causes the expected clinical phenotype or it does not, or they can be said to display variable expressivity, in which the same genotype can cause a wide range of clinical symptoms across a spectrum. Both incomplete penetrance and variable expressivity are thought to be caused by a range of factors, including common variants, variants in regulatory regions, epigenetics, environmental factors, and lifestyle. Many thousands of genetic variants have been identified as the cause of monogenic disorders, mostly determined through small clinical studies, and thus, the penetrance and expressivity of these variants may be overestimated when compared to their effect on the general population. With the wealth of population cohort data currently available, the penetrance and expressivity of such genetic variants can be investigated across a much wider contingent, potentially helping to reclassify variants that were previously thought to be completely penetrant. Research into the penetrance and expressivity of such genetic variants is important for clinical classification, both for determining causative mechanisms of disease in the affected population and for providing accurate risk information through genetic counseling. A genotype-based definition of the causes of rare diseases incorporating information from population cohorts and clinical studies is critical for our understanding of incomplete penetrance and variable expressivity. This review examines our current knowledge of the penetrance and expressivity of genetic variants in rare disease and across populations, as well as looking into the potential causes of the variation seen, including genetic modifiers, mosaicism, and polygenic factors, among others. We also considered the challenges that come with investigating penetrance and expressivity.
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Affiliation(s)
| | - Caroline F. Wright
- Institute of Biomedical and Clinical Science, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter, United Kingdom
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9
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Abstract
Inherited retinal dystrophies (IRDs) are a heterogeneous group of diseases that affect more than 2 million people worldwide. Gene therapy (GT) has emerged as an exciting treatment modality with the potential to provide long-term benefit to patients. Today, gene addition is the most straightforward GT for autosomal recessive IRDs. However, there are three scenarios where this approach falls short. First, in autosomal dominant diseases caused by gain-of-function or dominant-negative mutations, the toxic mutated protein needs to be silenced. Second, a number of IRD genes exceed the limited carrying capacity of adeno-associated virus vectors. Third, there are still about 30% of patients with unknown mutations. In the first two contexts, precise editing tools, such as CRISPR-Cas9, base editors, or prime editors, are emerging as potential GT solutions for the treatment of IRDs. Here, we review gene editing tools based on CRISPR-Cas9 technology that have been used in vivo and the recent first-in-human application of CRISPR-Cas9 in an IRD.
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Affiliation(s)
- Juliette Pulman
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France.,Fondation Ophtalmologique Rothschild, Paris, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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10
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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.
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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.
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11
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Peeters MHCA, Khan M, Rooijakkers AAMB, Mulders T, Haer-Wigman L, Boon CJF, Klaver CCW, van den Born LI, Hoyng CB, Cremers FPM, den Hollander AI, Dhaenens CM, Collin RWJ. PRPH2 mutation update: In silico assessment of 245 reported and 7 novel variants in patients with retinal disease. Hum Mutat 2021; 42:1521-1547. [PMID: 34411390 PMCID: PMC9290825 DOI: 10.1002/humu.24275] [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: 03/04/2021] [Revised: 07/22/2021] [Accepted: 08/16/2021] [Indexed: 01/31/2023]
Abstract
Mutations in PRPH2, encoding peripherin-2, are associated with the development of a wide variety of inherited retinal diseases (IRDs). To determine the causality of the many PRPH2 variants that have been discovered over the last decades, we surveyed all published PRPH2 variants up to July 2020, describing 720 index patients that in total carried 245 unique variants. In addition, we identified seven novel PRPH2 variants in eight additional index patients. The pathogenicity of all variants was determined using the ACMG guidelines. With this, 107 variants were classified as pathogenic, 92 as likely pathogenic, one as benign, and two as likely benign. The remaining 50 variants were classified as variants of uncertain significance. Interestingly, of the total 252 PRPH2 variants, more than half (n = 137) were missense variants. All variants were uploaded into the Leiden Open source Variation and ClinVar databases. Our study underscores the need for experimental assays for variants of unknown significance to improve pathogenicity classification, which would allow us to better understand genotype-phenotype correlations, and in the long-term, hopefully also support the development of therapeutic strategies for patients with PRPH2-associated IRD.
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Affiliation(s)
- Manon H C A Peeters
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | | | - Timo Mulders
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, Amsterdam, The Netherlands
| | - Caroline C W Klaver
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - L Ingeborgh van den Born
- The Rotterdam Eye Hospital, Rotterdam, The Netherlands.,Rotterdam Ophthalmic Institute, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Biochemistry and Molecular Biology, Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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12
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Next-Generation Sequencing Applications for Inherited Retinal Diseases. Int J Mol Sci 2021; 22:ijms22115684. [PMID: 34073611 PMCID: PMC8198572 DOI: 10.3390/ijms22115684] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal diseases (IRDs) represent a collection of phenotypically and genetically diverse conditions. IRDs phenotype(s) can be isolated to the eye or can involve multiple tissues. These conditions are associated with diverse forms of inheritance, and variants within the same gene often can be associated with multiple distinct phenotypes. Such aspects of the IRDs highlight the difficulty met when establishing a genetic diagnosis in patients. Here we provide an overview of cutting-edge next-generation sequencing techniques and strategies currently in use to maximise the effectivity of IRD gene screening. These techniques have helped researchers globally to find elusive causes of IRDs, including copy number variants, structural variants, new IRD genes and deep intronic variants, among others. Resolving a genetic diagnosis with thorough testing enables a more accurate diagnosis and more informed prognosis and should also provide information on inheritance patterns which may be of particular interest to patients of a child-bearing age. Given that IRDs are heritable conditions, genetic counselling may be offered to help inform family planning, carrier testing and prenatal screening. Additionally, a verified genetic diagnosis may enable access to appropriate clinical trials or approved medications that may be available for the condition.
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13
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Bolz HJ. Diagnostic Analyses of Retinal Dystrophy Genes: Current Status and Perspective. Klin Monbl Augenheilkd 2021; 238:261-266. [PMID: 33784789 DOI: 10.1055/a-1386-5361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the past decade, novel high-throughput DNA sequencing technologies have revolutionised both research and diagnostic testing for monogenic disorders. This applies particularly to genetically very heterogeneous disorders like retinal dystrophies (RDs). Next-generation sequencing (NGS) today is considered as reliable as Sanger sequencing, which had been the gold standard for decades. Today, comprehensive NGS-based diagnostic testing reveals the causative mutations in the majority of RD patients, with important implications for genetic counselling for recurrence risks and personalised medical management (from interdisciplinary surveillance to prophylactic measures and, albeit yet rare, [gene] therapy). While DNA sequencing is - in most cases - no longer the diagnostic bottleneck, one needs to be aware of interpretation pitfalls and dead ends. The advent of new (NGS) technologies will solve some of these issues. However, specialised medical geneticists who are familiar with the peculiarities of certain RD genes and closely interact with ophthalmologists will remain key to successful RD research and diagnostic testing for the benefit of the patients. This review sheds light on the current state of the field, its challenges and potential solutions.
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Affiliation(s)
- Hanno Jörn Bolz
- Humangenetik, Senckenberg Zentrum für Humangenetik, Frankfurt, Germany.,Humangenetik, University Hospital of Cologne, Cologne, Germany
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14
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de Bruijn SE, Fadaie Z, Cremers FPM, Kremer H, Roosing S. The Impact of Modern Technologies on Molecular Diagnostic Success Rates, with a Focus on Inherited Retinal Dystrophy and Hearing Loss. Int J Mol Sci 2021; 22:2943. [PMID: 33799353 PMCID: PMC7998853 DOI: 10.3390/ijms22062943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
The identification of pathogenic variants in monogenic diseases has been of interest to researchers and clinicians for several decades. However, for inherited diseases with extremely high genetic heterogeneity, such as hearing loss and retinal dystrophies, establishing a molecular diagnosis requires an enormous effort. In this review, we use these two genetic conditions as examples to describe the initial molecular genetic identification approaches, as performed since the early 90s, and subsequent improvements and refinements introduced over the years. Next, the history of DNA sequencing from conventional Sanger sequencing to high-throughput massive parallel sequencing, a.k.a. next-generation sequencing, is outlined, including their advantages and limitations and their impact on identifying the remaining genetic defects. Moreover, the development of recent technologies, also coined "third-generation" sequencing, is reviewed, which holds the promise to overcome these limitations. Furthermore, we outline the importance and complexity of variant interpretation in clinical diagnostic settings concerning the massive number of different variants identified by these methods. Finally, we briefly mention the development of novel approaches such as optical mapping and multiomics, which can help to further identify genetic defects in the near future.
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Affiliation(s)
- Suzanne E. de Bruijn
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
| | - Hannie Kremer
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
- Department of Otorhinolaryngology, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (S.E.d.B.); (Z.F.); (F.P.M.C.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands;
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15
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Allele frequency of variants reported to cause adenine phosphoribosyltransferase deficiency. Eur J Hum Genet 2021; 29:1061-1070. [PMID: 33707627 PMCID: PMC8298615 DOI: 10.1038/s41431-020-00805-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 12/01/2020] [Accepted: 12/21/2020] [Indexed: 11/15/2022] Open
Abstract
Adenine phosphoribosyltransferase deficiency is a rare, autosomal recessive disorder of purine metabolism that causes nephrolithiasis and progressive chronic kidney disease. The small number of reported cases indicates an extremely low prevalence, although it has been suggested that missed diagnoses may play a role. We assessed the prevalence of APRT deficiency based on the frequency of causally-related APRT sequence variants in a diverse set of large genomic databases. A thorough search was carried out for all APRT variants that have been confirmed as pathogenic under recessive mode of inheritance, and the frequency of the identified variants examined in six population genomic databases: the deCODE genetics database, the UK Biobank, the 100,000 Genomes Project, the Genome Aggregation Database, the Human Genetic Variation Database and the Korean Variant Archive. The estimated frequency of homozygous genotypes was calculated using the Hardy-Weinberg equation. Sixty-two pathogenic APRT variants were identified, including six novel variants. Most common were the missense variants c.407T>C (p.(Met136Thr)) in Japan and c.194A>T (p.(Asp65Val)) in Iceland, as well as the splice-site variant c.400 + 2dup (p.(Ala108Glufs*3)) in the European population. Twenty-nine variants were detected in at least one of the six genomic databases. The highest cumulative minor allele frequency (cMAF) of pathogenic variants outside of Japan and Iceland was observed in the Irish population (0.2%), though no APRT deficiency cases have been reported in Ireland. The large number of cases in Japan and Iceland is consistent with a founder effect in these populations. There is no evidence for widespread underdiagnosis based on the current analysis.
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16
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EYS is a major gene involved in retinitis pigmentosa in Japan: genetic landscapes revealed by stepwise genetic screening. Sci Rep 2020; 10:20770. [PMID: 33247286 PMCID: PMC7695703 DOI: 10.1038/s41598-020-77558-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 11/03/2020] [Indexed: 12/23/2022] Open
Abstract
Next-generation sequencing (NGS) has greatly advanced the studies of causative genes and variants of inherited diseases. While it is sometimes challenging to determine the pathogenicity of identified variants in NGS, the American College of Medical Genetics and Genomics established the guidelines to help the interpretation. However, as to the genetic screenings for patients with retinitis pigmentosa (RP) in Japan, none of the previous studies utilized the guidelines. Considering that EYS is the major causative gene of RP in Japan, we conducted stepwise genetic screening of 220 Japanese patients with RP utilizing the guidelines. Step 1-4 comprised the following, in order: Sanger sequencing for two major EYS founder mutations; targeted sequencing of all coding regions of EYS; whole genome sequencing; Sanger sequencing for Alu element insertion in RP1, a recently determined founder mutation for RP. Among the detected variants, 2, 19, 173, and 1 variant(s) were considered pathogenic and 8, 41, 44, and 5 patients were genetically solved in step 1, 2, 3, and 4, respectively. Totally, 44.5% (98/220) of the patients were genetically solved, and 50 (51.0%) were EYS-associated and 5 (5.1%) were Alu element-associated. Among the unsolved 122 patients, 22 had at least one possible pathogenic variant.
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17
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Green DJ, Sallah SR, Ellingford JM, Lovell SC, Sergouniotis PI. Variability in Gene Expression is Associated with Incomplete Penetrance in Inherited Eye Disorders. Genes (Basel) 2020; 11:genes11020179. [PMID: 32050448 PMCID: PMC7074066 DOI: 10.3390/genes11020179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/29/2020] [Accepted: 02/06/2020] [Indexed: 12/21/2022] Open
Abstract
Inherited eye disorders (IED) are a heterogeneous group of Mendelian conditions that are associated with visual impairment. Although these disorders often exhibit incomplete penetrance and variable expressivity, the scale and mechanisms of these phenomena remain largely unknown. Here, we utilize publicly-available genomic and transcriptomic datasets to gain insights into variable penetrance in IED. Variants in a curated set of 340 IED-implicated genes were extracted from the Human Gene Mutation Database (HGMD) 2019.1 and cross-checked with the Genome Aggregation Database (gnomAD) 2.1 control-only dataset. Genes for which >1 variants were encountered in both HGMD and gnomAD were considered to be associated with variable penetrance (n = 56). Variability in gene expression levels was then estimated for the subset of these genes that was found to be adequately expressed in two relevant resources: the Genotype-Tissue Expression (GTEx) and Eye Genotype Expression (EyeGEx) datasets. We found that genes suspected to be associated with variable penetrance tended to have significantly more variability in gene expression levels in the general population (p = 0.0000015); this finding was consistent across tissue types. The results of this study point to the possible influence of cis and/or trans-acting elements on the expressivity of variants causing Mendelian disorders. They also highlight the potential utility of quantifying gene expression as part of the investigation of families showing evidence of variable penetrance.
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Affiliation(s)
- David J. Green
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicines and Health, University of Manchester, Manchester M13 9PT, UK; (D.J.G.); (S.R.S.); (J.M.E.); (S.C.L.)
| | - Shalaw R. Sallah
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicines and Health, University of Manchester, Manchester M13 9PT, UK; (D.J.G.); (S.R.S.); (J.M.E.); (S.C.L.)
| | - Jamie M. Ellingford
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicines and Health, University of Manchester, Manchester M13 9PT, UK; (D.J.G.); (S.R.S.); (J.M.E.); (S.C.L.)
- Manchester Centre for Genomic Medicine, St Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK
| | - Simon C. Lovell
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicines and Health, University of Manchester, Manchester M13 9PT, UK; (D.J.G.); (S.R.S.); (J.M.E.); (S.C.L.)
| | - Panagiotis I. Sergouniotis
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicines and Health, University of Manchester, Manchester M13 9PT, UK; (D.J.G.); (S.R.S.); (J.M.E.); (S.C.L.)
- Manchester Centre for Genomic Medicine, St Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK
- Correspondence: ; Tel.: +44-(0)161-27-55748
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18
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Nikopoulos K, Cisarova K, Quinodoz M, Koskiniemi-Kuendig H, Miyake N, Farinelli P, Rehman AU, Khan MI, Prunotto A, Akiyama M, Kamatani Y, Terao C, Miya F, Ikeda Y, Ueno S, Fuse N, Murakami A, Wada Y, Terasaki H, Sonoda KH, Ishibashi T, Kubo M, Cremers FPM, Kutalik Z, Matsumoto N, Nishiguchi KM, Nakazawa T, Rivolta C. A frequent variant in the Japanese population determines quasi-Mendelian inheritance of rare retinal ciliopathy. Nat Commun 2019; 10:2884. [PMID: 31253780 PMCID: PMC6599023 DOI: 10.1038/s41467-019-10746-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 05/23/2019] [Indexed: 12/21/2022] Open
Abstract
Hereditary retinal degenerations (HRDs) are Mendelian diseases characterized by progressive blindness and caused by ultra-rare mutations. In a genomic screen of 331 unrelated Japanese patients, we identify a disruptive Alu insertion and a nonsense variant (p.Arg1933*) in the ciliary gene RP1, neither of which are rare alleles in Japan. p.Arg1933* is almost polymorphic (frequency = 0.6%, amongst 12,000 individuals), does not cause disease in homozygosis or heterozygosis, and yet is significantly enriched in HRD patients (frequency = 2.1%, i.e., a 3.5-fold enrichment; p-value = 9.2 × 10-5). Familial co-segregation and association analyses show that p.Arg1933* can act as a Mendelian mutation in trans with the Alu insertion, but might also associate with disease in combination with two alleles in the EYS gene in a non-Mendelian pattern of heredity. Our results suggest that rare conditions such as HRDs can be paradoxically determined by relatively common variants, following a quasi-Mendelian model linking monogenic and complex inheritance.
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Affiliation(s)
- Konstantinos Nikopoulos
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
- Service of Medical Genetics, Lausanne University Hospital (CHUV), 1011, Lausanne, Switzerland
| | - Katarina Cisarova
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Mathieu Quinodoz
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Hanna Koskiniemi-Kuendig
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Pietro Farinelli
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Atta Ur Rehman
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 GA, Nijmegen, The Netherlands
| | - Andrea Prunotto
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Masato Akiyama
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Yoichiro Kamatani
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Chikashi Terao
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Fuyuki Miya
- Department of Medical Science Mathematics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Nobuo Fuse
- Department of Integrative Genomics, Tohoku Medical Megabank Organization, Sendai, 980-8573, Japan
| | - Akira Murakami
- Department of Ophthalmology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan
| | - Yuko Wada
- Yuko Wada Eye Clinic, Sendai, 980-0011, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Tatsuro Ishibashi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Michiaki Kubo
- RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 GA, Nijmegen, The Netherlands
| | - Zoltán Kutalik
- Institute of Social and Preventive Medicine, Lausanne University Hospital, 1011, Lausanne, Switzerland
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Koji M Nishiguchi
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Carlo Rivolta
- Unit of Medical Genetics, Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland.
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK.
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland.
- University of Basel, 4001, Basel, Switzerland.
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