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Lambiri DW, Levin LA. Maculopapillary Bundle Degeneration in Optic Neuropathies. Curr Neurol Neurosci Rep 2024; 24:203-218. [PMID: 38833037 DOI: 10.1007/s11910-024-01343-0] [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] [Accepted: 05/16/2024] [Indexed: 06/06/2024]
Abstract
PURPOSE OF REVIEW Degeneration of the maculopapillary bundle (MPB) is a prominent feature in a spectrum of optic neuropathies. MPB-selective degeneration is seen in specific conditions, such as nutritional and toxic optic neuropathies, Leber hereditary optic neuropathy (LHON), and dominant optic atrophy (DOA). Despite their distinct etiologies and clinical presentations, which encompass variations in age of incidence and monocular or binocular onset, these disorders share a core molecular mechanism: compromised mitochondrial homeostasis. This disruption is characterized by dysfunctions in mitochondrial metabolism, biogenesis, and protein synthesis. This article provides a comprehensive understanding of the MPB's role in optic neuropathies, emphasizing the importance of mitochondrial mechanisms in the pathogenesis of these conditions. RECENT FINDINGS Optical coherence tomography studies have characterized the retinal nerve fiber layer changes accompanying mitochondrial-affiliated optic neuropathies. Selective thinning of the temporal optic nerve head is preceded by thickening in early stages of these disorders which correlates with reductions in macular ganglion cell layer thinning and vascular atrophy. A recently proposed mechanism underpinning the selective atrophy of the MPB involves the positive feedback of reactive oxygen species generation as a common consequence of mitochondrial dysfunction. Additionally, new research has revealed that the MPB can undergo degeneration in the early stages of glaucoma, challenging the historically held belief that this area was not involved in this common optic neuropathy. A variety of anatomical risk factors influence the propensity of glaucomatous MPB degeneration, and cases present distinct patterns of ganglion cell degeneration that are distinct from those observed in mitochondria-associated diseases. This review synthesizes clinical and molecular research on primary MPB disorders, highlighting the commonalities and differences in their pathogenesis. KEY POINTS (BOX) 1. Temporal degeneration of optic nerve fibers accompanied by cecocentral scotoma is a hallmark of maculopapillary bundle (MPB) degeneration. 2. Mechanisms of MPB degeneration commonly implicate mitochondrial dysfunction. 3. Recent research challenges the traditional belief that the MPB is uninvolved in glaucoma by showing degeneration in the early stages of this common optic neuropathy, yet with features distinct from other MPB-selective neuropathies. 4. Reactive oxygen species generation is a mechanism linking mitochondrial mechanisms of MPB-selective optic neuropathies, but in-vivo and in-vitro studies are needed to validate this hypothesis.
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Affiliation(s)
- Darius W Lambiri
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada.
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.
- Department of Neurology & Neurosurgery, McGill University, Montreal, Canada.
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2
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Delibes C, Ferré M, Rozet M, Desquiret-Dumas V, Descatha A, Gohier B, Gohier P, Amati-Bonneau P, Milea D, Reynier P. Genetic susceptibility to optic neuropathy in patients with alcohol use disorder. J Transl Med 2024; 22:495. [PMID: 38796496 PMCID: PMC11127293 DOI: 10.1186/s12967-024-05334-0] [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: 02/27/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024] Open
Abstract
BACKGROUND The pathophysiology of toxico-nutritional optic neuropathies remains debated, with no clear understanding of the respective roles played by the direct alcohol toxicity, smoking and the often associated vitamin deficiencies, which are risk factors for optic neuropathy. Our aim was to investigate genetic susceptibility in patients with bilateral infraclinical optic neuropathy associated with chronic alcohol use disorder. METHODS This retrospective cohort study included 102 visually asymptomatic patients with documented alcohol use disorder from a French reference center. Optic neuropathy was identified with optical coherence tomography (OCT), after which genetic susceptibility in the group of affected patients was investigated. Genetic testing was performed using panel sequencing of 87 nuclear genes and complete mitochondrial DNA sequencing. RESULTS Optic neuropathy was detected in 36% (37/102) of the included patients. Genetic testing of affected patients disclosed two patients (2/30, 6.7%) with optic neuropathy associated with pathogenic variants affecting the SPG7 gene and five patients (5/30, 16.7%) who harbored variants of uncertain significance close to probable pathogenicity in the genes WFS1, LOXL1, MMP19, NR2F1 and PMPCA. No pathogenic mitochondrial DNA variants were found in this group. CONCLUSIONS OCT can detect presence of asymptomatic optic neuropathy in patients with chronic alcohol use disorder. Furthermore, genetic susceptibility to optic neuropathy in this setting is found in almost a quarter of affected patients. Further studies may clarify the role of preventative measures in patients who might be predisposed to avoidable visual loss and blindness.
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Affiliation(s)
- Camille Delibes
- Département d'Ophtalmologie, Centre Hospitalier Universitaire (CHU), 49000, Angers, France
| | - Marc Ferré
- Université d'Angers, Unité Mixte de Recherche (UMR) MITOVASC, Institut National de la Santé et de la Recherche Médicale (INSERM U-1083), Centre National de la Recherche Scientifique (CNRS 6015), 49000, Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire, 49000, Angers, France
| | - Marine Rozet
- Département de Psychiatrie et d'Addictologie, Centre Hospitalier Universitaire, 49000, Angers, France
| | - Valérie Desquiret-Dumas
- Université d'Angers, Unité Mixte de Recherche (UMR) MITOVASC, Institut National de la Santé et de la Recherche Médicale (INSERM U-1083), Centre National de la Recherche Scientifique (CNRS 6015), 49000, Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire, 49000, Angers, France
| | - Alexis Descatha
- Univ. Angers (University of Angers), CHU Angers, Univ. Rennes, Inserm, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail) - UMR_S 1085, IRSET-ESTER, SFR ICAT, CAPTV CDC, 49000, Angers, France
- Department of Occupational Medicine, Epidemiology and Prevention, Donald and Barbara Zucker School of Medicine, Hosftra University Northwell Health, New York, NY, 11021, USA
| | - Bénédicte Gohier
- Département de Psychiatrie et d'Addictologie, Centre Hospitalier Universitaire, 49000, Angers, France
- Univ Angers, Université de Nantes, LPPL, SFR CONFLUENCES, 49000, Angers, France
| | - Philippe Gohier
- Département d'Ophtalmologie, Centre Hospitalier Universitaire (CHU), 49000, Angers, France
| | - Patrizia Amati-Bonneau
- Université d'Angers, Unité Mixte de Recherche (UMR) MITOVASC, Institut National de la Santé et de la Recherche Médicale (INSERM U-1083), Centre National de la Recherche Scientifique (CNRS 6015), 49000, Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire, 49000, Angers, France
| | - Dan Milea
- Département d'Ophtalmologie, Centre Hospitalier Universitaire (CHU), 49000, Angers, France
- Singapore National Eye Centre, Singapore Eye Research Institute, Duke-NUS, Singapore, Singapore
- Rothschild Foundation Hospital, Paris, France
| | - Pascal Reynier
- Université d'Angers, Unité Mixte de Recherche (UMR) MITOVASC, Institut National de la Santé et de la Recherche Médicale (INSERM U-1083), Centre National de la Recherche Scientifique (CNRS 6015), 49000, Angers, France.
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire, 49000, Angers, France.
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Ladero M, Reche-Sainz JA, Gallardo ME. Hereditary Optic Neuropathies: A Systematic Review on the Interplay between Biomaterials and Induced Pluripotent Stem Cells. Bioengineering (Basel) 2024; 11:52. [PMID: 38247929 PMCID: PMC10813088 DOI: 10.3390/bioengineering11010052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/29/2023] [Accepted: 12/30/2023] [Indexed: 01/23/2024] Open
Abstract
Hereditary optic neuropathies (HONs) such as dominant optic atrophy (DOA) and Leber Hereditary Optic Neuropathy (LHON) are mitochondrial diseases characterized by a degenerative loss of retinal ganglion cells (RGCs) and are a cause of blindness worldwide. To date, there are only limited disease-modifying treatments for these disorders. The discovery of induced pluripotent stem cell (iPSC) technology has opened several promising opportunities in the field of HON research and the search for therapeutic approaches. This systematic review is focused on the two most frequent HONs (LHON and DOA) and on the recent studies related to the application of human iPSC technology in combination with biomaterials technology for their potential use in the development of RGC replacement therapies with the final aim of the improvement or even the restoration of the vision of HON patients. To this purpose, the combination of natural and synthetic biomaterials modified with peptides, neurotrophic factors, and other low- to medium-molecular weight compounds, mimicking the ocular extracellular matrices, with human iPSC or iPSC-derived cell retinal progenitors holds enormous potential to be exploited in the near future for the generation of transplantable RGC populations.
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Affiliation(s)
- Miguel Ladero
- FQPIMA Group, Materials and Chemical Engineering Department, Chemical Sciences School, Complutense University of Madrid, 28040 Madrid, Spain
| | - Jose Alberto Reche-Sainz
- Ophthalmology Unit, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- Translational Research with iPS Cells Group, Research Institute of Hospital 12 de Octubre, imas12, 28041 Madrid, Spain
| | - M. Esther Gallardo
- Translational Research with iPS Cells Group, Research Institute of Hospital 12 de Octubre, imas12, 28041 Madrid, Spain
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Einhorn Y, Einhorn M, Kurolap A, Steinberg D, Mory A, Bazak L, Paperna T, Grinshpun-Cohen J, Basel-Salmon L, Weiss K, Singer A, Yaron Y, Baris Feldman H. Community data-driven approach to identify pathogenic founder variants for pan-ethnic carrier screening panels. Hum Genomics 2023; 17:30. [PMID: 36978159 PMCID: PMC10044388 DOI: 10.1186/s40246-023-00472-w] [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: 08/21/2022] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND The American College of Medical Genetics and Genomics (ACMG) recently published new tier-based carrier screening recommendations. While many pan-ethnic genetic disorders are well established, some genes carry pathogenic founder variants (PFVs) that are unique to specific ethnic groups. We aimed to demonstrate a community data-driven approach to creating a pan-ethnic carrier screening panel that meets the ACMG recommendations. METHODS Exome sequencing data from 3061 Israeli individuals were analyzed. Machine learning determined ancestries. Frequencies of candidate pathogenic/likely pathogenic (P/LP) variants based on ClinVar and Franklin were calculated for each subpopulation based on the Franklin community platform and compared with existing screening panels. Candidate PFVs were manually curated through community members and the literature. RESULTS The samples were automatically assigned to 13 ancestries. The largest number of samples was classified as Ashkenazi Jewish (n = 1011), followed by Muslim Arabs (n = 613). We detected one tier-2 and seven tier-3 variants that were not included in existing carrier screening panels for Ashkenazi Jewish or Muslim Arab ancestries. Five of these P/LP variants were supported by evidence from the Franklin community. Twenty additional variants were detected that are potentially pathogenic tier-2 or tier-3. CONCLUSIONS The community data-driven and sharing approaches facilitate generating inclusive and equitable ethnically based carrier screening panels. This approach identified new PFVs missing from currently available panels and highlighted variants that may require reclassification.
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Affiliation(s)
| | | | - Alina Kurolap
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
| | | | - Adi Mory
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
| | - Lily Bazak
- Beilinson Hospital, Rabin Medical Center, Recanati Genetics Institute, Petah Tikva, Israel
| | - Tamar Paperna
- Rambam Health Care Campus, The Genetics Institute, Haifa, Israel
| | | | - Lina Basel-Salmon
- Beilinson Hospital, Rabin Medical Center, Recanati Genetics Institute, Petah Tikva, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Karin Weiss
- Rambam Health Care Campus, The Genetics Institute, Haifa, Israel
- The Ruth and Bruce Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Amihood Singer
- Community Genetic Services, Ministry of Health, Tel Aviv, Israel
| | - Yuval Yaron
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Baris Feldman
- The Genetics Institute and Genomics Center, Tel Aviv Sourasky Medical Center, 6 Weizmann St., Tel Aviv, Israel.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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5
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Rocatcher A, Desquiret-Dumas V, Charif M, Ferré M, Gohier P, Mirebeau-Prunier D, Verny C, Milea D, Lenaers G, Bonneau D, Reynier P, Amati-Bonneau P. The top 10 most frequently involved genes in hereditary optic neuropathies in 2186 probands. Brain 2023; 146:455-460. [PMID: 36317462 DOI: 10.1093/brain/awac395] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/15/2022] [Accepted: 09/25/2022] [Indexed: 12/12/2022] Open
Abstract
Hereditary optic neuropathies are caused by the degeneration of retinal ganglion cells whose axons form the optic nerves, with a consistent genetic heterogeneity. As part of our diagnostic activity, we retrospectively evaluated the combination of Leber hereditary optic neuropathy mutations testing with the exon sequencing of 87 nuclear genes on 2186 patients referred for suspected hereditary optic neuropathies. The positive diagnosis rate in individuals referred for Leber hereditary optic neuropathy testing was 18% (199/1126 index cases), with 92% (184/199) carrying one of the three main pathogenic variants of mitochondrial DNA (m.11778G>A, 66.5%; m.3460G>A, 15% and m.14484T>C, 11%). The positive diagnosis rate in individuals referred for autosomal dominant or recessive optic neuropathies was 27% (451/1680 index cases), with 10 genes accounting together for 96% of this cohort. This represents an overall positive diagnostic rate of 30%. The identified top 10 nuclear genes included OPA1, WFS1, ACO2, SPG7, MFN2, AFG3L2, RTN4IP1, TMEM126A, NR2F1 and FDXR. Eleven additional genes, each accounting for less than 1% of cases, were identified in 17 individuals. Our results show that 10 major genes account for more than 96% of the cases diagnosed with our nuclear gene panel.
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Affiliation(s)
- Aude Rocatcher
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Valérie Desquiret-Dumas
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Majida Charif
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Genetics and Immuno-Cell Therapy Team, Mohammed First University, Oujda 60000, Morocco
| | - Marc Ferré
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Philippe Gohier
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Delphine Mirebeau-Prunier
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
| | - Christophe Verny
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Neurologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Dan Milea
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
- Singapore National Eye Centre, Singapore Eye Research Institute, Duke-NUS 169857, Singapore
| | - Guy Lenaers
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Neurologie, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Dominique Bonneau
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Génétique, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Pascal Reynier
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
| | - Patrizia Amati-Bonneau
- Université d'Angers, Centre National de la Recherche Scientifique (CNRS 6015), Institut National de la Santé et de la Recherche Médicale (INSERM U1083), Unité Mixte de Recherche (UMR) MITOVASC, 49000 Angers, France
- Département de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire d'Angers, 49933 Angers, France
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Petrovic Pajic S, Lapajne L, Vratanar B, Fakin A, Jarc-Vidmar M, Sustar Habjan M, Volk M, Maver A, Peterlin B, Hawlina M. The Relative Preservation of the Central Retinal Layers in Leber Hereditary Optic Neuropathy. J Clin Med 2022; 11:jcm11206045. [PMID: 36294366 PMCID: PMC9604528 DOI: 10.3390/jcm11206045] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/30/2022] [Accepted: 10/08/2022] [Indexed: 11/22/2022] Open
Abstract
(1) Background: The purpose of this study was to evaluate the thickness of retinal layers in Leber hereditary optic neuropathy (LHON) in the atrophic stage compared with presumably inherited bilateral optic neuropathy of unknown cause with the aim of seeing if any LHON-specific patterns exist. (2) Methods: 14 patients (24 eyes) with genetically confirmed LHON (LHON group) were compared with 13 patients (23 eyes) with negative genetic testing results (mtDNA + WES) and without identified etiology of bilateral optic atrophy (nonLHON group). Segmentation analysis of retinal layers in the macula and peripapillary RNFL (pRNFL) measurements was performed using Heidelberg Engineering Spectralis SD-OCT. (3) Results: In the LHON group, the thickness of ganglion cell complex (GCC) (retinal nerve fiber layer (RNFL)—ganglion cell layer (GCL)—inner plexiform layer (IPL)) in the central ETDRS (Early Treatment Diabetic Retinopathy Study) circle was significantly higher than in the nonLHON group (p < 0.001). In all other ETDRS fields, GCC was thinner in the LHON group. The peripapillary RNFL (pRNFL) was significantly thinner in the LHON group in the temporal superior region (p = 0.001). Longitudinal analysis of our cohort during the follow-up time showed a tendency of thickening of the RNFL, GCL, and IPL in the LHON group in the central circle, as well as a small recovery of the pRNFL in the temporal region, which corresponds to the observed central macular thickening. (4) Conclusions: In LHON, the retinal ganglion cell complex thickness (RNFL-GCL-IPL) appears to be relatively preserved in the central ETDRS circle compared to nonLHON optic neuropathies in the chronic phase. Our findings may represent novel biomarkers as well as a structural basis for possible recovery in some patients with LHON.
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Affiliation(s)
- Sanja Petrovic Pajic
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
- Clinic for Eye Diseases, University Clinical Centre of Serbia, Pasterova 2, 11000 Belgrade, Serbia
| | - Luka Lapajne
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
| | - Bor Vratanar
- Institute for Biostatistics and Medical Informatics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
| | - Martina Jarc-Vidmar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
| | - Maja Sustar Habjan
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
| | - Marija Volk
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Šlajmajerjeva ulica 4, 1000 Ljubljana, Slovenia
| | - Ales Maver
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Šlajmajerjeva ulica 4, 1000 Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Šlajmajerjeva ulica 4, 1000 Ljubljana, Slovenia
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +386-1-522-1900; Fax: +386-1-522-1960
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7
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Seo Y, Kim TY, Won D, Shin S, Choi JR, Lee ST, Lee BJ, Lim HT, Han SH, Han J. Genetic spectrum and characteristics of autosomal optic neuropathy in Korean: Use of next-generation sequencing in suspected hereditary optic atrophy. Front Neurol 2022; 13:978532. [PMID: 36071901 PMCID: PMC9441910 DOI: 10.3389/fneur.2022.978532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
AimsTo evaluate the clinical characteristics and causative genetic variants in autosomal optic atrophy diagnosed using next-generation sequencing (NGS).MethodsA cohort of 57 unrelated families affected with bilateral optic atrophy were recruited from two university-based tertiary referral hospitals from May 2016 to April 2022. Genetic variants were detected using a target enrichment panel consisting of 429 or 595 genes and known deep intronic variants associated with inherited eye diseases, exome sequencing, or genome sequencing. The results of detailed clinical examinations, disease-causing variants, and clinical diagnoses were analyzed.ResultsAmong the 57 probands, 33 (57.9%) were men, and the median age at genetic testing was 19.1 years (interquartile range, 7.6–42.5 years). We identified 22 likely causative variants in 18 families and corresponding diagnostic yields of 31.6% (95% confidence interval, 21.0–44.5%). The diagnostic rate of NGS was higher in patients with infantile or early childhood onset optic atrophy than in those with late-onset or unknown optic atrophy (18/39, 46.2% vs. 0/18, 0%, P < 0.001). Among the 22 variants, 15 were novel in our cohort. The OPA1 variants (n = 7) were found to be the major genetic causes, followed by the NR2F1 variant (n = 4). The causative variants in PTPN23, TMEM126A, NBAS, and WFS1 genes were identified in 4 probands with a recessive form of optic atrophy.ConclusionsBased on the results of diagnostic NGS for optic atrophy, the causative variant could be detected in 31.6% of patients. Our study also demonstrated that NGS is unlikely to help identify molecular causes in late-onset unexplained optic atrophy.
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Affiliation(s)
- Yuri Seo
- Department of Ophthalmology, Institute of Vision Research, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea
| | - Tae Young Kim
- Department of Ophthalmology, Institute of Vision Research, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Dongju Won
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Saeam Shin
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Dxome Co., Ltd., Seongnam-si, South Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Dxome Co., Ltd., Seongnam-si, South Korea
| | - Byung Joo Lee
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Hyun Taek Lim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
- Seoul Orthopia Eye Clinic, Seoul, South Korea
| | - Sueng-Han Han
- Department of Ophthalmology, Institute of Vision Research, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
- Sueng-Han Han
| | - Jinu Han
- Department of Ophthalmology, Institute of Vision Research, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
- *Correspondence: Jinu Han
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Functional characterization of variants of unknown significance in a spinocerebellar ataxia patient using an unsupervised machine learning pipeline. Hum Genome Var 2022; 9:10. [PMID: 35422034 PMCID: PMC9010413 DOI: 10.1038/s41439-022-00188-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/08/2022] [Accepted: 02/23/2022] [Indexed: 01/15/2023] Open
Abstract
CAG-expanded ATXN7 has been previously defined in the pathogenesis of spinocerebellar ataxia type 7 (SCA7), a polyglutamine expansion autosomal dominant cerebellar ataxia. Pathology in SCA7 occurs as a result of a CAG triplet repeat expansion in excess of 37 in the first exon of ATXN7, which encodes ataxin-7. SCA7 presents clinically with spinocerebellar ataxia and cone-rod dystrophy. Here, we present a novel spinocerebellar ataxia variant occurring in a patient with mutations in both ATXN7 and TOP1MT, which encodes mitochondrial topoisomerase I (top1mt). Using machine-guided, unbiased microscopy image analysis, we demonstrate alterations in ataxin-7 subcellular localization, and through high-fidelity measurements of cellular respiration, bioenergetic defects in association with top1mt mutations. We identify ataxin-7 Q35P and top1mt R111W as deleterious mutations, potentially contributing to disease states. We recapitulate our mutations through Drosophila genetic models. Our work provides important insight into the cellular biology of ataxin-7 and top1mt and offers insight into the pathogenesis of spinocerebellar ataxia applicable to multiple subtypes of the illness. Moreover, our study demonstrates an effective pipeline for the characterization of previously unreported genetic variants at the level of cell biology.
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Charif M, Gueguen N, Ferré M, Elkarhat Z, Khiati S, LeMao M, Chevrollier A, Desquiret-Dumas V, Goudenège D, Bris C, Kane S, Alban J, Chupin S, Wetterwald C, Caporali L, Tagliavini F, LaMorgia C, Carbonelli M, Jurkute N, Barakat A, Gohier P, Verny C, Barth M, Procaccio V, Bonneau D, Zanlonghi X, Meunier I, Weisschuh N, Schimpf-Linzenbold S, Tonagel F, Kellner U, Yu-Wai-Man P, Carelli V, Wissinger B, Amati-Bonneau P, Reynier P, Lenaers G. Dominant ACO2 mutations are a frequent cause of isolated optic atrophy. Brain Commun 2021; 3:fcab063. [PMID: 34056600 PMCID: PMC8152918 DOI: 10.1093/braincomms/fcab063] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/24/2022] Open
Abstract
Biallelic mutations in ACO2, encoding the mitochondrial aconitase 2, have been identified in individuals with neurodegenerative syndromes, including infantile cerebellar retinal degeneration and recessive optic neuropathies (locus OPA9). By screening European cohorts of individuals with genetically unsolved inherited optic neuropathies, we identified 61 cases harbouring variants in ACO2, among whom 50 carried dominant mutations, emphasizing for the first time the important contribution of ACO2 monoallelic pathogenic variants to dominant optic atrophy. Analysis of the ophthalmological and clinical data revealed that recessive cases are affected more severely than dominant cases, while not significantly earlier. In addition, 27% of the recessive cases and 11% of the dominant cases manifested with extraocular features in addition to optic atrophy. In silico analyses of ACO2 variants predicted their deleterious impacts on ACO2 biophysical properties. Skin derived fibroblasts from patients harbouring dominant and recessive ACO2 mutations revealed a reduction of ACO2 abundance and enzymatic activity, and the impairment of the mitochondrial respiration using citrate and pyruvate as substrates, while the addition of other Krebs cycle intermediates restored a normal respiration, suggesting a possible short-cut adaptation of the tricarboxylic citric acid cycle. Analysis of the mitochondrial genome abundance disclosed a significant reduction of the mitochondrial DNA amount in all ACO2 fibroblasts. Overall, our data position ACO2 as the third most frequently mutated gene in autosomal inherited optic neuropathies, after OPA1 and WFS1, and emphasize the crucial involvement of the first steps of the Krebs cycle in the maintenance and survival of retinal ganglion cells.
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Affiliation(s)
- Majida Charif
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Genetics and Immuno-Cell Therapy Team, Mohammed First University, Oujda, Morocco
| | - Naïg Gueguen
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - Marc Ferré
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Zouhair Elkarhat
- Laboratory of Genomics and Human Genetics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Salim Khiati
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Morgane LeMao
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Arnaud Chevrollier
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Valerie Desquiret-Dumas
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - David Goudenège
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - Céline Bris
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - Selma Kane
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Jennifer Alban
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Stéphanie Chupin
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | | | - Leonardo Caporali
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Francesca Tagliavini
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Chiara LaMorgia
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Michele Carbonelli
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Neringa Jurkute
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
- Cambridge Eye Unit, Addenbrooke’s Hospital, Cambridge University Hospitals, Cambridge, UK
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Abdelhamid Barakat
- Laboratory of Genomics and Human Genetics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Philippe Gohier
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
| | - Christophe Verny
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Centre de référence des Maladies Neurogénétiques, Département de Neurologie, CHU d’Angers, Angers, France
| | - Magalie Barth
- Department of Pediatrics, Competence Center of Inherited Metabolic Disorders, Angers Hospital, Angers, France
| | - Vincent Procaccio
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - Dominique Bonneau
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | | | - Isabelle Meunier
- National Center for Rare Diseases, Genetics of Sensory Diseases, University Hospital, Montpellier, France
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | | | - Felix Tonagel
- Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ulrich Kellner
- Rare Retinal Disease Center, AugenZentrum Siegburg, MVZ ADTC Siegburg GmbH, Siegburg, Germany
- RetinaScience, 53113 Bonn, Germany
| | - Patrick Yu-Wai-Man
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
- Cambridge Eye Unit, Addenbrooke’s Hospital, Cambridge University Hospitals, Cambridge, UK
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Valerio Carelli
- Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Patrizia Amati-Bonneau
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | - Pascal Reynier
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Département de Biochimie et Génétique, CHU d'Angers, Angers, France
| | | | - Guy Lenaers
- Université Angers, MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, SFR ICAT, Angers, France
- Correspondence to: Guy Lenaers MitoLab Team, Mitochondrial Medicine Research Centre, MitoVasc Unit, Université d'Angers UMR CNRS 6015, INSERM U1083, CHU Bât IRIS/IBS, Rue des Capucins 49933 Angers cedex 9, France E-mail:
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10
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Gibson S, Azamian MS, Lalani SR, Yen KG, Sutton VR, Scott DA. Recessive ACO2 variants as a cause of isolated ophthalmologic phenotypes. Am J Med Genet A 2020; 182:1960-1966. [PMID: 32449285 DOI: 10.1002/ajmg.a.61634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/15/2020] [Accepted: 05/04/2020] [Indexed: 12/20/2022]
Abstract
The mitochondrial aconitase gene (ACO2) encodes an enzyme that catalyzes the conversion of citrate to isocitrate in the tricarboxylic acid cycle. Biallelic variants in ACO2 are purported to cause two distinct disorders: infantile cerebellar-retinal degeneration (ICRD) which is characterized by CNS abnormalities, neurodevelopmental phenotypes, optic atrophy and retinal degeneration; and optic atrophy 9 (OPA9), characterized by isolated ophthalmologic phenotypes including optic atrophy and low vision. However, some doubt remains as to whether biallelic ACO2 variants can cause isolated ophthalmologic phenotypes. A review of the literature revealed five individuals from three families who carry biallelic ACO2 variants whose phenotypes are consistent with OPA9. Here, we describe a brother and sister with OPA9 who are compound heterozygous for novel missense variants in ACO2; c.[487G>T];[1894G>A], p.[(Val163Leu)];[(Val632Met)]. A review of pathogenic ACO2 variants revealed that those associated with OPA9 are distinct from those associated with ICRD. Missense variants associated with either OPA9 or ICRD do not cluster in distinct ACO2 domains, making it difficult to predict the severity of a variant based on position alone. We conclude that biallelic variants in ACO2 can cause the milder OPA9 phenotype, and that the OPA9-related ACO2 variants identified to date are distinct from those that cause ICRD.
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Affiliation(s)
- Shelley Gibson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Mahshid S Azamian
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Kimberly G Yen
- Texas Children's Hospital, Houston, Texas, USA
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children's Hospital, Houston, Texas, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
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