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Bouzidi A, Charoute H, Charif M, Amalou G, Kandil M, Barakat A, Lenaers G. Clinical and genetic spectrums of 413 North African families with inherited retinal dystrophies and optic neuropathies. Orphanet J Rare Dis 2022; 17:197. [PMID: 35551639 PMCID: PMC9097391 DOI: 10.1186/s13023-022-02340-7] [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: 11/18/2021] [Accepted: 04/26/2022] [Indexed: 11/26/2022] Open
Abstract
Background Inherited retinal dystrophies (IRD) and optic neuropathies (ION) are the two major causes world-wide of early visual impairment, frequently leading to legal blindness. These two groups of pathologies are highly heterogeneous and require combined clinical and molecular diagnoses to be securely identified. Exact epidemiological studies are lacking in North Africa, and genetic studies of IRD and ION individuals are often limited to case reports or to some families that migrated to the rest of the world. In order to improve the knowledge of their clinical and genetic spectrums in North Africa, we reviewed published data, to illustrate the most prevalent pathologies, genes and mutations encountered in this geographical region, extending from Morocco to Egypt, comprising 200 million inhabitants. Main body We compiled data from 413 families with IRD or ION together with their available molecular diagnosis. The proportion of IRD represents 82.8% of index cases, while ION accounted for 17.8%. Non-syndromic IRD were more frequent than syndromic ones, with photoreceptor alterations being the main cause of non-syndromic IRD, represented by retinitis pigmentosa, Leber congenital amaurosis, and cone-rod dystrophies, while ciliopathies constitute the major part of syndromic-IRD, in which the Usher and Bardet Biedl syndromes occupy 41.2% and 31.1%, respectively. We identified 71 ION families, 84.5% with a syndromic presentation, while surprisingly, non-syndromic ION are scarcely reported, with only 11 families with autosomal recessive optic atrophies related to OPA7 and OPA10 variants, or with the mitochondrial related Leber ION. Overall, consanguinity is a major cause of these diseases within North African countries, as 76.1% of IRD and 78.8% of ION investigated families were consanguineous, explaining the high rate of autosomal recessive inheritance pattern compared to the dominant one. In addition, we identified many founder mutations in small endogamous communities. Short conclusion As both IRD and ION diseases constitute a real public health burden, their under-diagnosis in North Africa due to the absence of physicians trained to the identification of inherited ophthalmologic presentations, together with the scarcity of tools for the molecular diagnosis represent major political, economic and health challenges for the future, to first establish accurate clinical diagnoses and then treat patients with the emergent therapies. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02340-7.
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Affiliation(s)
- Aymane Bouzidi
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, CHU d'Angers, CNRS 6015, Université d'Angers, 49933, Angers, France.,Genomics and Human Genetics Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco.,Team of Anthropogenetics and Biotechnologies, Faculty of Sciences, Chouaïb Doukkali University, Eljadida, Morocco
| | - Hicham Charoute
- Research Unit of Epidemiology, Biostatistics and Bioinformatics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Majida Charif
- Genetics, and Immuno-Cell Therapy Team, Mohamed First University, Oujda, Morocco
| | - Ghita Amalou
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, CHU d'Angers, CNRS 6015, Université d'Angers, 49933, Angers, France.,Genomics and Human Genetics Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco.,Team of Anthropogenetics and Biotechnologies, Faculty of Sciences, Chouaïb Doukkali University, Eljadida, Morocco
| | - Mostafa Kandil
- Team of Anthropogenetics and Biotechnologies, Faculty of Sciences, Chouaïb Doukkali University, Eljadida, Morocco
| | - Abdelhamid Barakat
- Genomics and Human Genetics Laboratory, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Guy Lenaers
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, CHU d'Angers, CNRS 6015, Université d'Angers, 49933, Angers, France. .,Service de Neurologie, CHU d'Angers, Angers, France.
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Haploinsufficiency due to a novel ACO2 deletion causes mitochondrial dysfunction in fibroblasts from a patient with dominant optic nerve atrophy. Sci Rep 2020; 10:16736. [PMID: 33028849 PMCID: PMC7541502 DOI: 10.1038/s41598-020-73557-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 09/02/2020] [Indexed: 01/20/2023] Open
Abstract
ACO2 is a mitochondrial protein, which is critically involved in the function of the tricarboxylic acid cycle (TCA), the maintenance of iron homeostasis, oxidative stress defense and the integrity of mitochondrial DNA (mtDNA). Mutations in the ACO2 gene were identified in patients suffering from a broad range of symptoms, including optic nerve atrophy, cortical atrophy, cerebellar atrophy, hypotonia, seizures and intellectual disabilities. In the present study, we identified a heterozygous 51 bp deletion (c.1699_1749del51) in ACO2 in a family with autosomal dominant inherited isolated optic atrophy. A complementation assay using aco1-deficient yeast revealed a growth defect for the mutant ACO2 variant substantiating a pathogenic effect of the deletion. We used patient-derived fibroblasts to characterize cellular phenotypes and found a decrease of ACO2 protein levels, while ACO2 enzyme activity was not affected compared to two age- and gender-matched control lines. Several parameters of mitochondrial function, including mitochondrial morphology, mitochondrial membrane potential or mitochondrial superoxide production, were not changed under baseline conditions. However, basal respiration, maximal respiration, and spare respiratory capacity were reduced in mutant cells. Furthermore, we observed a reduction of mtDNA copy number and reduced mtDNA transcription levels in ACO2-mutant fibroblasts. Inducing oxidative stress led to an increased susceptibility for cell death in ACO2-mutant fibroblasts compared to controls. Our study reveals that a monoallelic mutation in ACO2 is sufficient to promote mitochondrial dysfunction and increased vulnerability to oxidative stress as main drivers of cell death related to optic nerve atrophy.
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Sivakumar P, Singh J, Vedachalam R. Bilateral Optic Atrophy in an Adolescent Male Patient. JAMA Ophthalmol 2019; 137:101-102. [DOI: 10.1001/jamaophthalmol.2018.2594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Priya Sivakumar
- Department of Neuro-ophthalmology, Aravind Eye Care, Pondicherry, India
| | - Jivitesh Singh
- Department of Neuro-ophthalmology, Aravind Eye Care, Pondicherry, India
| | - Rajesh Vedachalam
- Department of Neuro-ophthalmology, Aravind Eye Care, Pondicherry, India
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Ribas VT, Koch JC, Michel U, Bähr M, Lingor P. Attenuation of Axonal Degeneration by Calcium Channel Inhibitors Improves Retinal Ganglion Cell Survival and Regeneration After Optic Nerve Crush. Mol Neurobiol 2016; 54:72-86. [PMID: 26732591 DOI: 10.1007/s12035-015-9676-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/21/2015] [Indexed: 01/08/2023]
Abstract
Axonal degeneration is one of the initial steps in many traumatic and neurodegenerative central nervous system (CNS) disorders and thus a promising therapeutic target. A focal axonal lesion is followed by acute axonal degeneration (AAD) of both adjacent axon parts, before proximal and distal parts follow different degenerative fates at later time points. Blocking calcium influx by calcium channel inhibitors was previously shown to attenuate AAD after optic nerve crush (ONC). However, it remains unclear whether the attenuation of AAD also promotes consecutive axonal regeneration. Here, we used a rat ONC model to study the effects of calcium channel inhibitors on axonal degeneration, retinal ganglion cell (RGC) survival, and axonal regeneration, as well as the molecular mechanisms involved. Application of calcium channel inhibitors attenuated AAD after ONC and preserved axonal integrity as visualized by live imaging of optic nerve axons. Consecutively, this resulted in improved survival of RGCs and improved axonal regeneration at 28 days after ONC. We show further that calcium channel inhibition attenuated lesion-induced calpain activation in the proximity of the crush and inhibited the activation of the c-Jun N-terminal kinase pathway. Pro-survival signaling via Akt in the retina was also increased. Our data thus show that attenuation of AAD improves consecutive neuronal survival and axonal regeneration and that calcium channel inhibitors could be valuable tools for therapeutic interventions in traumatic and degenerative CNS disorders.
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Affiliation(s)
- Vinicius T Ribas
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Jan C Koch
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Uwe Michel
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. .,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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Sudden occurrence of Roth spots and retinal hemorrhages following endoscopic adhesiolysis: an SD-OCT evaluation. Eur J Ophthalmol 2015; 26:e11-3. [PMID: 26428215 DOI: 10.5301/ejo.5000679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To document the occurrence of Roth spots and retinal hemorrhages by spectral-domain optical coherence tomography (SD-OCT) following endoscopic adhesiolysis for failed back surgery syndrome. METHODS Case report. RESULTS A 47-year-old patient noted progressive and bilateral visual loss immediately after epidural endoscopy and endoscopic adhesiolysis. Funduscopic examination showed multiple Roth spots and retinal hemorrhages at the posterior pole and the retinal midperiphery in both eyes. Spectral-domain optical coherence tomography demonstrated that Roth spots involved the inner retina, while dot hemorrhages involved the outer retina. Most retinal hemorrhages and Roth spots resolved over 6 weeks, with complete functional recovery in both eyes. However, SD-OCT revealed multiple areas of disruption of the outer retinal layers in the left eye. CONCLUSIONS Roth spots and retinal hemorrhages can occur after endoscopic spinal surgery. Although hemorrhages resolve quickly over few weeks, SD-OCT can demonstrate that retinal damage might persist, especially in the outer retina. This finding may explain cases of incomplete recovery of visual function after complicated endoscopic adhesiolysis.
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Hereditäre Optikusatrophien. MED GENET-BERLIN 2014. [DOI: 10.1007/s11825-014-0435-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Zusammenfassung
Bei hereditären Optikusatrophien werden 2 Untergruppen differenziert: isolierte hereditäre Optikusatrophien und hereditäre Optikusatrophien als Teil von syndromalen Erkrankungen. In der 1. Gruppe ist die Beeinträchtigung des N. opticus typischerweise die einzige Manifestation. Diese Gruppe umfasst insbesondere autosomal-dominante und autosomal-rezessive Optikusatrophien, darüber hinaus auch die mitochondrial vererbte hereditäre Leber-Optikusneuropathie (LHON).
In der 2. Gruppe, die die syndromalen Erkrankungen umfasst, wird eine Vielzahl neurologischer und anderer systemischer Auffälligkeiten beobachtet. Am häufigsten sind hier Veränderungen der mitochondrialen DNA (mtDNA) ursächlich. Weiterhin ist eine Optikusatrophie Symptom von einigen erblichen peripheren Neuropathien bzw. Charcot-Marie-Tooth-Erkrankungen (CMT2A2, CMTX5), hereditären sensorischen Neuropathie Typ 3 (HSAN3), Friedreich-Ataxie, Leukodystrophien, Sphingolipidosen, Zeroidlipofuszinosen und Eisenspeichererkrankungen („neurodegeneration with brain iron accumulation“, NBIA). Im vorliegenden Beitrag werden die zugrundeliegenden genetischen Prädispositionen und die klinischen Phänotypen erläutert.
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Neuhann T, Rautenstrauss B. Genetic and phenotypic variability of optic neuropathies. Expert Rev Neurother 2013; 13:357-67. [PMID: 23545052 DOI: 10.1586/ern.13.19] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hereditary optic neuropathies comprise a group of clinically and genetically heterogeneous disorders. Two subgroups can be formed: isolated hereditary optic atrophies and optic neuropathy as part of complex disorders. In group 1 of hereditary optic neuropathies, optic nerve dysfunction is typically the only manifestation of the disease. This group comprises autosomal dominant, autosomal recessive and X-linked recessive optic atrophy and the maternally inherited Leber's hereditary optic neuropathy. Among the autosomal-dominant forms of optic atrophy, Kjer's disease is most frequently observed. In the second group of complex disorders, various neurologic and other systemic abnormalities are regularly observed. Most frequent in this group are mtDNA mutations, inherited peripheral neuropathies, Charcot-Marie-Tooth disorders (CMT2A2, CMTX5), hereditary sensory neuropathy type 3 (HSAN3), Friedreich's ataxia, leukodystrophies, sphingolipidoses, ceroid-lipofuscinoses and neurodegeneration with brain iron accumulation. We review current knowledge about the underlying genetic predispositions, the most urgent open questions and how this may affect our management of this heterogeneous group of disorders in the future.
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Affiliation(s)
- Teresa Neuhann
- Medizinisch Genetisches Zentrum, Munich, Bayerstrasse 3-5, Munich 80335, Germany.
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O'Neill EC, Mackey DA, Connell PP, Hewitt AW, Danesh-Meyer HV, Crowston JG. The optic nerve head in hereditary optic neuropathies. Nat Rev Neurol 2009; 5:277-87. [DOI: 10.1038/nrneurol.2009.40] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
AIMS To provide a clinical update on the hereditary optic neuropathies. METHODS Review of the literature. RESULTS The hereditary optic neuropathies comprise a group of disorders in which the cause of optic nerve dysfunction appears to be hereditable, based on familial expression or genetic analysis. In some hereditary optic neuropathies, optic nerve dysfunction is typically the only manifestation of the disease. In others, various neurologic and systemic abnormalities are regularly observed. CONCLUSION The most common hereditary optic neuropathies are autosomal dominant optic atrophy (Kjer's disease) and maternally inherited Leber's hereditary optic neuropathy. We review the clinical phenotypes of these and other inherited disorders with optic nerve involvement.
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MESH Headings
- Dysautonomia, Familial/complications
- Dysautonomia, Familial/genetics
- Female
- Friedreich Ataxia/complications
- Friedreich Ataxia/genetics
- Humans
- Male
- Muscular Dystrophies/complications
- Muscular Dystrophies/genetics
- Optic Atrophies, Hereditary/complications
- Optic Atrophies, Hereditary/genetics
- Optic Atrophies, Hereditary/physiopathology
- Optic Atrophy, Autosomal Dominant/complications
- Optic Atrophy, Autosomal Dominant/genetics
- Optic Atrophy, Autosomal Dominant/physiopathology
- Optic Atrophy, Hereditary, Leber/complications
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/physiopathology
- Pedigree
- Spinocerebellar Ataxias/complications
- Spinocerebellar Ataxias/genetics
- Vision Disorders/etiology
- Vision Disorders/genetics
- Vision Disorders/physiopathology
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Affiliation(s)
- N J Newman
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA 30022, USA.
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Chung JE, Spaide RF, Warren FA. Dural Arteriovenous Malformation and Superior Ophthalmic Vein Occlusion. Retina 2004; 24:491-2. [PMID: 15187685 DOI: 10.1097/00006982-200406000-00033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Juliet E Chung
- Vitreous-Retina-Macula-Consultants of New York, New York 10021, USA
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