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Lan X, Ao WL, Li J. Preimplantation genetic testing as a preventive strategy for the transmission of mitochondrial DNA disorders. Syst Biol Reprod Med 2024; 70:38-51. [PMID: 38323618 DOI: 10.1080/19396368.2024.2306389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/07/2024] [Indexed: 02/08/2024]
Abstract
Mitochondrial diseases are distinct types of metabolic and/or neurologic abnormalities that occur as a consequence of dysfunction in oxidative phosphorylation, affecting several systems in the body. There is no effective treatment modality for mitochondrial disorders so far, emphasizing the clinical significance of preventing the inheritance of these disorders. Various reproductive options are available to reduce the probability of inheriting mitochondrial disorders, including in vitro fertilization (IVF) using donated oocytes, preimplantation genetic testing (PGT), and prenatal diagnosis (PND), among which PGT not only makes it possible for families to have genetically-owned children but also PGT has the advantage that couples do not have to decide to terminate the pregnancy if a mutation is detected in the fetus. PGT for mitochondrial diseases originating from nuclear DNA includes analyzing the nuclear genome for the presence or absence of corresponding mutations. However, PGT for mitochondrial disorders arising from mutations in mitochondrial DNA (mtDNA) is more intricate, due to the specific characteristics of mtDNA such as multicopy nature, heteroplasmy phenomenon, and exclusive maternal inheritance. Therefore, the present review aims to discuss the utility and challenges of PGT as a preventive approach to inherited mitochondrial diseases caused by mtDNA mutations.
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Affiliation(s)
- Xinpeng Lan
- College of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, China
| | - Wu Liji Ao
- College of Mongolian Medicine and Pharmacy, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, China
| | - Ji Li
- College of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin, China
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Pant K, Sharma A, Menon SV, Ali H, Hassan Almalki W, Kaur M, Deorari M, Kazmi I, Mahajan S, Kalra H, Alzarea SI. Exploring ncRNAs in epilepsy: From oxidative stress regulation to therapy. Brain Res 2024; 1841:149089. [PMID: 38880410 DOI: 10.1016/j.brainres.2024.149089] [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: 04/22/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
Epilepsy is a prevalent neurological illness which is linked with high worldwide burdens. Oxidative stress (OS) is recognized to be among the contributors that trigger the advancement of epilepsy, affecting neuronal excitability and synaptic transmission. Various types of non-coding RNAs (ncRNAs) are known to serve vital functions in many disease mechanisms, including epilepsy. The current review sought to understand better the mechanisms through which these ncRNAs regulate epilepsy's OS-related pathways. We investigated the functions of microRNAs in controlling gene expression at the post-translatory stage and their involvement in OS and neuroinflammation. We also looked at the different regulatory roles of long ncRNAs, including molecular scaffolding, enhancer, and transcriptional activator, during OS. Circular RNAs and their capability to act as miRNA decoys and their consequential impact on epilepsy development were also explored. Our review aimed to improve the current understanding of novel therapies for epilepsy based on the role of ncRNAs in OS pathways. We also demonstrated the roles of ncRNAs in epilepsy treatment and diagnosis, explaining that these molecules play vital roles that could be used in therapy as biomarkers.
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Affiliation(s)
- Kumud Pant
- Graphic Era (Deemed to be University), Clement Town Dehradun, 248002, India; Graphic Era Hill University Clement Town Dehradun, 248002, India
| | - Aanchal Sharma
- Chandigarh Pharmacy College, Chandigarh Group of Colleges, Jhanjheri, Mohali 140307, Punjab, India
| | - Soumya V Menon
- Department of Biotechnology and Genetics, Jain (Deemed-to-be) University, Bengaluru, Karnataka 560069, India; Department of Allied Healthcare and Sciences, Vivekananda Global University, Jaipur, Rajasthan 303012, India
| | - Haider Ali
- Centre for Global Health Research, Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, India; Department of Pharmacology, Kyrgyz State Medical College, Bishkek, Kyrgyzstan.
| | - Waleed Hassan Almalki
- Department of Pharmacology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Mandeep Kaur
- Department of Sciences, Vivekananda Global University, Jaipur, Rajasthan 303012, India
| | - Mahamedha Deorari
- School of Basic & Applied Sciences, Shobhit University, Gangoh, Uttar Pradesh-247341, India; Department of Health & Allied Sciences, Arka Jain University, Jamshedpur, Jharkhand- 831001, India
| | - Imran Kazmi
- Department of Biochemistry, Faculty of Science, King Abdulaziz University, 21589, Jeddah, Saudi Arabia
| | - Shriya Mahajan
- Centre of Research Impact and Outcome, Chitkara University, Rajpura 140417, Punjab, India
| | - Hitesh Kalra
- Chitkara Centre for Research and Development, Chitkara University, Himachal Pradesh 174103, India
| | - Sami I Alzarea
- Department of Pharmacology, College of Pharmacy, Jouf University, 72341, Sakaka, Aljouf, Saudi Arabia
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da Palma MM, Marra M, Igelman AD, Ku CA, Burr A, Andersen K, Everett LA, Porto FBO, Sallum JMF, Yang P, Pennesi ME. Expanding the phenotypic and genotypic spectrum of patients with HGSNAT-related retinopathy. Ophthalmic Genet 2024; 45:167-174. [PMID: 37592806 DOI: 10.1080/13816810.2023.2245035] [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: 03/12/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023]
Abstract
BACKGROUND Variants in HGSNAT have historically been associated with syndromic mucopolysaccharidosis type IIIC (MPSIIIC) but more recent studies demonstrate cases of HGSNAT-related non-syndromic retinitis pigmentosa. We describe and expand the genotypic and phenotypic spectrum of this disease. MATERIALS AND METHODS This is a retrospective, observational, case series of 11 patients with pericentral retinitis pigmentosa due to variants in HGSNAT gene without a syndromic diagnosis of MPSIIIC. We reviewed ophthalmologic data extracted from medical records, genetic testing, color fundus photos, fundus autofluorescence (FAF), and optical coherence tomography (OCT). RESULTS Of the 11 patients, the mean age was 52 years (range: 26-78). The mean age of ophthalmologic symptoms onset was 45 years (range: 15-72). The visual acuity varied from 20/20 to 20/80 (mean 20/30 median 20/20). We described five novel variants in HGSNAT: c.715del (p.Arg239Alafs *37), c.118 G>A (p.Asp40Asn), c.1218_1220delinsTAT, c.1297A>G (p.Asn433Asp), and c.1726 G>T (p.Gly576*). CONCLUSIONS HGSNAT has high phenotypic heterogeneity. Data from our cohort showed that all patients who had at least one variant of c.1843 G>A (p.Ala615Thr) presented with the onset of ocular symptoms after the fourth decade of life. The two patients with onset of ocular symptoms before the fourth decade did not carry this variant. This may suggest that c.1843 G>A variant is associated with a later onset of retinopathy.
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Affiliation(s)
- Mariana Matioli da Palma
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
- Department of Ophthalmology and Visual Sciences, Universidade Federal de São Paulo Escola Paulista de Medicina (UNIFESP), São Paulo, Brazil
- Instituto de Genética Ocular, São Paulo, Brazil
- Department of Surgery & Hospital Clinic of Barcelona, School of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Molly Marra
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Austin D Igelman
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Cristy A Ku
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, California, USA
| | - Amanda Burr
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Katherine Andersen
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Lesley A Everett
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | | | - Juliana Maria Ferraz Sallum
- Department of Ophthalmology and Visual Sciences, Universidade Federal de São Paulo Escola Paulista de Medicina (UNIFESP), São Paulo, Brazil
- Instituto de Genética Ocular, São Paulo, Brazil
| | - Paul Yang
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
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Beckman M, Clevenger L, DeBenedictis MJ, Yuan A, Sharma S. A novel ocular phenotype associated with pathogenic variants in MFSD8 leading to macular dystrophy. Ophthalmic Genet 2023; 44:606-609. [PMID: 36861499 DOI: 10.1080/13816810.2023.2183224] [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: 11/07/2022] [Revised: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 03/03/2023]
Abstract
BACKGROUND The major facilitator superfamily domain-containing protein 8 (MFSD8) pathogenic variants are classically associated with autosomal recessive neuronal ceroid lipofuscinosis-7. Case reports have recently demonstrated an association of MFSD8 variants causing autosomal recessive macular dystrophy with central cone involvement without neurologic sequelae. We report a patient with a novel ocular phenotype associated with MFSD8 pathogenic variants causing macular dystrophy without systemic findings. CASE PRESENTATION A 37-year-old female presented with a 20-year history of progressive bilateral vision loss. Fundus examination was notable for a slight pigmentary ring around the fovea in both eyes. Optical coherence tomography (OCT) of the macula showed bilateral subfoveal ellipsoid zone loss without outer retinal changes. Fundus autofluorescence (FAF) demonstrated foveal hypo-autofluorescence (AF) in both eyes as well as hyper-AF nasally to the optic nerve in the perifoveal area. Full-field and multifocal electroretinography demonstrated cone dysfunction with diffuse macular changes in both eyes. Subsequent genetic testing identified two pathogenic MFSD8 variants. The patient had no neurologic symptoms consistent with variant-late infantile neuronal ceroid lipofuscinosis. CONCLUSION MFSD8 pathogenic variants are known to cause macular dystrophies. We report a novel MFSD8-associated macular dystrophy phenotype demonstrating foveal-limited disease with cavitary changes on OCT without inner retinal atrophy and foveal-specific changes on FAF. A threshold model can explain how a hypomorphic missense variant heterozygous with a loss-of-function nonsense variant can lead to a predominantly ocular phenotype with preserved neurologic function. We recommend careful monitoring of these patients for future signs of both retinal and systemic disease progression.
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Affiliation(s)
- Madeline Beckman
- School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | | | | | - Alex Yuan
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Sumit Sharma
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Poncet AF, Grunewald O, Vaclavik V, Meunier I, Drumare I, Pelletier V, Bocquet B, Todorova MG, Le Moing AG, Devos A, Schorderet DF, Jobic F, Defoort-Dhellemmes S, Dollfus H, Smirnov VM, Dhaenens CM. Contribution of Whole-Genome Sequencing and Transcript Analysis to Decipher Retinal Diseases Associated with MFSD8 Variants. Int J Mol Sci 2022; 23:ijms23084294. [PMID: 35457110 PMCID: PMC9032189 DOI: 10.3390/ijms23084294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 01/01/2023] Open
Abstract
Biallelic gene defects in MFSD8 are not only a cause of the late-infantile form of neuronal ceroid lipofuscinosis, but also of rare isolated retinal degeneration. We report clinical and genetic data of seven patients compound heterozygous or homozygous for variants in MFSD8, issued from a French cohort with inherited retinal degeneration, and two additional patients retrieved from a Swiss cohort. Next-generation sequencing of large panels combined with whole-genome sequencing allowed for the identification of twelve variants from which seven were novel. Among them were one deep intronic variant c.998+1669A>G, one large deletion encompassing exon 9 and 10, and a silent change c.750A>G. Transcript analysis performed on patients’ lymphoblastoid cell lines revealed the creation of a donor splice site by c.998+1669A>G, resulting in a 140 bp pseudoexon insertion in intron 10. Variant c.750A>G produced exon 8 skipping. In silico and in cellulo studies of these variants allowed us to assign the pathogenic effect, and showed that the combination of at least one severe variant with a moderate one leads to isolated retinal dystrophy, whereas the combination in trans of two severe variants is responsible for early onset severe retinal dystrophy in the context of late-infantile neuronal ceroid lipofuscinosis.
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Affiliation(s)
- Anaïs F. Poncet
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Veronika Vaclavik
- University of Lausanne, Jules-Gonin Eye Hospital, 1004 Lausanne, Switzerland;
- Cantonal Hospital, Department of Ophthalmology, 1700 Fribourg, Switzerland
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Isabelle Drumare
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Margarita G. Todorova
- Department of Ophthalmology, Cantonal Hospital, 9007 St. Gallen, Switzerland;
- Department of Ophthalmology, University of Zürich, 8091 Zürich, Switzerland
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland
| | - Anne-Gaëlle Le Moing
- Department of Child Neurology, Amiens-Picardy University Hospital, F-80000 Amiens, France;
| | - Aurore Devos
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Daniel F. Schorderet
- Faculty of Biology and Medicine, University of Lausanne and Faculty of Life Sciences, Ecole Polytechnique Fédérale of Lausanne, 1004 Lausanne, Switzerland;
| | - Florence Jobic
- Unité de Génétique Médicale et Oncogénétique, Centre Hospitalier Universitaire Amiens Picardie, F-80000 Amiens, France;
| | - Sabine Defoort-Dhellemmes
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Vasily M. Smirnov
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
- Université de Lille, Faculté de Médecine, F-59000 Lille, France
| | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
- Correspondence: ; Tel.: +33-320444953
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A Novel, Apparently Silent Variant in MFSD8 Causes Neuronal Ceroid Lipofuscinosis with Marked Intrafamilial Variability. Int J Mol Sci 2022; 23:ijms23042271. [PMID: 35216386 PMCID: PMC8877174 DOI: 10.3390/ijms23042271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Variants in MFSD8 can cause neuronal ceroid lipofuscinoses (NCLs) as well as nonsyndromic retinopathy. The mutation spectrum includes mainly missense and stop variants, but splice sites and frameshift variants have also been reported. To date, apparently synonymous substitutions have not been shown to cause MFSD8-associated diseases. We report two closely related subjects from a consanguineous Turkish family who presented classical features of NCLs but demonstrated marked intrafamilial variability in age at the onset and severity of symptoms. In fact, the difference in the onset of first neurologic symptoms was 15 years and that of ophthalmologic symptoms was 12 years. One subject presented an intellectual disability and a considerable cerebellar ataxia syndrome, while the other subject showed no intellectual disability and only a mild atactic syndrome. The diagnostic genetic testing of both subjects based on genome sequencing prioritized a novel, apparently synonymous variant in MFSD8, which was found in homozygosity in both subjects. The variant was not located within an integral part of the splice site consensus sequences. However, the bioinformatic analyses suggested that the mutant allele is more likely to cause exon skipping due to an altered ratio of exonic splice enhancer and silencer motifs. Exon skipping was confirmed in vitro by minigene assays and in vivo by RNA analysis from patient lymphocytes. The mutant transcript is predicted to result in a frameshift and, if translated, in a truncated protein. Synonymous variants are often given a low priority in genetic diagnostics because of their expected lack of functional impact. This study highlights the importance of investigating the impact of synonymous variants on splicing.
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