1
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D'Costa MS, Bugiardini E, Merve A, Morrow JM. PYROXD1-associated myopathy. BMJ Case Rep 2024; 17:e259907. [PMID: 38553017 PMCID: PMC10982700 DOI: 10.1136/bcr-2024-259907] [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] [Indexed: 04/02/2024] Open
Abstract
PYROXD1-associated myopathy is a rare genetic form of limb-girdle muscular dystrophy (LGMD) with only 23 previous cases having been reported in the literature. The exact role of PYROXD1 in the pathophysiology of LGMD remains unclear. We describe two brothers who presented to the neuromuscular clinic with progressive weakness of their upper and lower limbs over the preceding decades. Our case highlights how recent advancements in genetic sequencing have revolutionised the diagnostic classification process for LGMD and provided opportunities to establish diagnoses for previously unclassified myopathies. We also illustrate how the increased adoption of muscle MRI to identify disease and target muscle biopsy can provide better quality and more informative samples for classification. Finally, our report details the clinical and histopathological findings found in both cases adding valuable data to the currently limited information published on PYROXD1-associated myopathy.
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Affiliation(s)
| | - Enrico Bugiardini
- Queen Square Centre for Neuromuscular Diseases, Queen Square UCL Institute of Neurology, London, UK
| | - Ashirwad Merve
- Neuropathology, Great Ormond Street Hospital for Children, London, UK
| | - Jasper M Morrow
- Queen Square Centre for Neuromuscular Diseases, Queen Square UCL Institute of Neurology, London, UK
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2
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Sainio MT, Aaltio J, Hyttinen V, Kortelainen M, Ojanen S, Paetau A, Tienari P, Ylikallio E, Auranen M, Tyynismaa H. Effectiveness of clinical exome sequencing in adult patients with difficult-to-diagnose neurological disorders. Acta Neurol Scand 2022; 145:63-72. [PMID: 34418069 DOI: 10.1111/ane.13522] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/02/2021] [Accepted: 08/12/2021] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Clinical diagnostics in adults with hereditary neurological diseases is complicated by clinical and genetic heterogeneity, as well as lifestyle effects. Here, we evaluate the effectiveness of exome sequencing and clinical costs in our difficult-to-diagnose adult patient cohort. Additionally, we expand the phenotypic and genetic spectrum of hereditary neurological disorders in Finland. METHODS We performed clinical exome sequencing (CES) to 100 adult patients from Finland with neurological symptoms of suspected genetic cause. The patients were classified as myopathy (n = 57), peripheral neuropathy (n = 16), ataxia (n = 15), spastic paraplegia (n = 4), Parkinsonism (n = 3), and mixed (n = 5). In addition, we gathered the costs of prior diagnostic work-up to retrospectively assess the cost-effectiveness of CES as a first-line diagnostic tool. RESULTS The overall diagnostic yield of CES was 27%. Pathogenic variants were found for 14 patients (in genes ANO5, CHCHD10, CLCN1, DES, DOK7, FKBP14, POLG, PYROXD1, SCN4A, TUBB3, and TTN) and likely pathogenic previously undescribed variants for 13 patients (in genes ABCD1, AFG3L2, ATL1, CACNA1A, COL6A1, DYSF, IRF2BPL, KCNA1, MT-ATP6, SAMD9L, SGCB, and TPM2). Age of onset below 40 years increased the probability of finding a genetic cause. Our cost evaluation of prior diagnostic work-up suggested that early CES would be cost-effective in this patient group, in which diagnostic costs increase linearly with prolonged investigations. CONCLUSIONS Based on our results, CES is a cost-effective, powerful first-line diagnostic tool in establishing the molecular diagnosis in adult neurological patients with variable symptoms. Importantly, CES can markedly shorten the diagnostic odysseys of about one third of patients.
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Affiliation(s)
- Markus T. Sainio
- Stem Cells and Metabolism Research Program Faculty of Medicine University of Helsinki Helsinki Finland
| | - Juho Aaltio
- Stem Cells and Metabolism Research Program Faculty of Medicine University of Helsinki Helsinki Finland
| | - Virva Hyttinen
- VATT Institute for Economic Research Helsinki Finland
- Department of Health and Social Management University of Eastern Finland Kuopio Finland
| | - Mika Kortelainen
- VATT Institute for Economic Research Helsinki Finland
- Department of Economics Turku School of Economics Turku Finland
| | - Simo Ojanen
- Department of Veterinary Biosciences Faculty of Veterinary Medicine University of Helsinki Helsinki Finland
| | - Anders Paetau
- Department of Pathology HUSLAB and University of Helsinki Helsinki Finland
| | - Pentti Tienari
- Clinical Neurosciences Neurology University of Helsinki and Helsinki University Hospital Helsinki Finland
- Translational Immunology Research Program Faculty of Medicine University of Helsinki Helsinki Finland
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program Faculty of Medicine University of Helsinki Helsinki Finland
- Clinical Neurosciences Neurology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Mari Auranen
- Clinical Neurosciences Neurology University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program Faculty of Medicine University of Helsinki Helsinki Finland
- Department of Medical and Clinical Genetics University of Helsinki Helsinki Finland
- Neuroscience Center Helsinki Institute of Life Science University of Helsinki Helsinki Finland
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3
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Cabrera-Serrano M, Caccavelli L, Savarese M, Vihola A, Jokela M, Johari M, Capiod T, Madrange M, Bugiardini E, Brady S, Quinlivan R, Merve A, Scalco R, Hilton-Jones D, Houlden H, Ibrahim Aydin H, Ceylaner S, Vockley J, Taylor RL, Folland C, Kelly A, Goullee H, Ylikallio E, Auranen M, Tyynismaa H, Udd B, Forrest ARR, Davis MR, Bratkovic D, Manton N, Robertson T, McCombe P, Laing NG, Phillips L, de Lonlay P, Ravenscroft G. Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis. Brain 2021; 145:3985-3998. [DOI: 10.1093/brain/awab484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/04/2021] [Accepted: 12/10/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified ten bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) predisposing individuals to recurrent rhabdomyolysis. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in SR function and Ca2+ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in SR Ca2+ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca2+ back into the SR and/or a decrease in Ca2+ SR storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease.
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Affiliation(s)
- Macarena Cabrera-Serrano
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
- Unidad de Enfermedades Neuromusculares. Servicio de Neurologia y Neurofisiologia. Hospital Virgen del Rocio, Sevilla, Spain
| | - Laure Caccavelli
- Inserm U1151, Institut Necker Enfants-Malades, Reference Center of Inherited Metabolic Diseases and MetabERN, Necker-Enfants-Malades Hospital, Paris University, Paris, France
| | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland and Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Anna Vihola
- Folkhälsan Research Center, Helsinki, Finland and Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Tampere Neuromuscular Center, Tampere University Hospital, Tampere, Finland
| | - Manu Jokela
- Neuromuscular Research Center, Department of Neurology, Tampere University and University Hospital, Tampere, Finland
- Neurocenter, Department of Neurology, Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland and Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Thierry Capiod
- Inserm U1151, Institut Necker Enfants-Malades, Reference Center of Inherited Metabolic Diseases and MetabERN, Necker-Enfants-Malades Hospital, Paris University, Paris, France
| | - Marine Madrange
- Inserm U1151, Institut Necker Enfants-Malades, Reference Center of Inherited Metabolic Diseases and MetabERN, Necker-Enfants-Malades Hospital, Paris University, Paris, France
| | - Enrico Bugiardini
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Stefen Brady
- Department of Neurology, Southmead Hospital, Bristol, UK
| | - Rosaline Quinlivan
- MRC Centre for Neuromuscular Diseases, University College Hospitals, London, UK
| | - Ashirwad Merve
- MRC Centre for Neuromuscular Diseases, University College Hospitals, London, UK
| | - Renata Scalco
- MRC Centre for Neuromuscular Diseases, University College Hospitals, London, UK
| | - David Hilton-Jones
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London, UK
| | | | - Serdar Ceylaner
- Intergen Genetic Diagnosis and Research Center, Ankara, Turkey
| | - Jerry Vockley
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rhonda L. Taylor
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Chiara Folland
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Aasta Kelly
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
| | - Hayley Goullee
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Emil Ylikallio
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Mari Auranen
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland and Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
- Tampere Neuromuscular Center, Tampere University Hospital, Tampere, Finland
| | - Alistair R. R. Forrest
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Mark R. Davis
- Department of Diagnostic Genomics, PathWest Laboratory Medicine WA, Nedlands, WA, Australia
| | - Drago Bratkovic
- Metabolic Clinic, Women and Children’s Hospital, North Adelaide, SA, Australia
| | - Nicholas Manton
- SA Pathology, Women and Children’s Hospital, North Adelaide, SA, Australia
| | - Thomas Robertson
- Anatomical Pathology, Queensland Pathology, Brisbane, Queensland, Australia
| | - Pamela McCombe
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
- Centre for Clinical Research, The University of Queensland Centre for Clinical Research, Brisbane, Queensland, Australia
| | - Nigel G. Laing
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
- Department of Diagnostic Genomics, PathWest Laboratory Medicine WA, Nedlands, WA, Australia
| | - Liza Phillips
- SA Pathology, Women and Children’s Hospital, North Adelaide, SA, Australia
- The University of Adelaide, Adelaide, SA, Australia
| | - Pascale de Lonlay
- Inserm U1151, Institut Necker Enfants-Malades, Reference Center of Inherited Metabolic Diseases and MetabERN, Necker-Enfants-Malades Hospital, Paris University, Paris, France
| | - Gianina Ravenscroft
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
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4
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Yeast as a Tool to Understand the Significance of Human Disease-Associated Gene Variants. Genes (Basel) 2021; 12:genes12091303. [PMID: 34573285 PMCID: PMC8465565 DOI: 10.3390/genes12091303] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 02/05/2023] Open
Abstract
At present, the great challenge in human genetics is to provide significance to the growing amount of human disease-associated gene variants identified by next generation DNA sequencing technologies. Increasing evidences suggest that model organisms are of pivotal importance to addressing this issue. Due to its genetic tractability, the yeast Saccharomyces cerevisiae represents a valuable model organism for understanding human genetic variability. In the present review, we show how S. cerevisiae has been used to study variants of genes involved in different diseases and in different pathways, highlighting the versatility of this model organism.
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5
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Daimagüler HS, Akpulat U, Özdemir Ö, Yis U, Güngör S, Talim B, Diniz G, Baydan F, Thiele H, Altmüller J, Nürnberg P, Cirak S. Clinical and genetic characterization of PYROXD1-related myopathy patients from Turkey. Am J Med Genet A 2021; 185:1678-1690. [PMID: 33694278 DOI: 10.1002/ajmg.a.62148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/07/2021] [Accepted: 02/07/2021] [Indexed: 11/08/2022]
Abstract
Congenital myopathies (CMs) are a heterogeneous group of inherited muscle disorders characterized by muscle weakness at birth, while limb-girdle muscular dystrophies (LGMD) have a later onset and slower disease progression. Thus, detailed clinical phenotyping of genetically defined disease entities are required for the full understanding of genotype-phenotype correlations. A recently defined myopathic genetic disease entity is caused by bi-allelic variants in a gene coding for pyridine nucleotide-disulfide oxidoreductase domain 1 (PYROXD1) with unknown substrates. Here, we present three patients from two consanguineous Turkish families with mild LGMD, facial weakness, normal CK levels, and slow progress. Genomic analyses revealed a homozygous known pathogenic missense variant (c.464A>G, p.Asn155Ser) in family 1 with two affected females. In the affected male of family 2, we found this variant in a compound heterozygous state together with a novel frameshift variant (c.329_332delTCTG, p.Leu112Valfs*8), which is the second frameshift variant known so far in PYROXD1. We have been able to define a large homozygous region in family 1 sharing a common haplotype with family 2 in the critical region. Our data suggest that c.464A>G is a Turkish founder mutation. To gain deeper insights, we performed a systematic review of all published PYROXD1-related myopathy cases. Our analysis showed that the c.464A > G variant was found in 87% (20/23) of the patients and that it may cause either a childhood- or adult-onset phenotype, irrespective of its presence in a homozygous or compound heterozygous state. Interestingly, only four patients had elevated CK levels (up to 1000 U/L), and cardiac involvement was found in few compound heterozygous cases.
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Affiliation(s)
- Hülya-Sevcan Daimagüler
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Ugur Akpulat
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Department of Medical Biology, Faculty of Medicine, Kastamonu University, Kastamonu, Turkey
| | - Özkan Özdemir
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Uluc Yis
- Faculty of Medicine, Department of Pediatric Neurology Izmir, Dokuz Eylül University, Izmir, Turkey
| | - Serdal Güngör
- Faculty of Medicine, Turgut Ozal Research Center, Department of Paediatric Neurology, Inönü University Malatya, Malatya, Turkey
| | - Beril Talim
- Pediatric Pathology Unit, Department of Pediatrics, Hacettepe University Ankara, Ankara, Turkey
| | - Gülden Diniz
- Department of Pathology, Izmir Democracy University, Izmir, Turkey
| | - Figen Baydan
- Division of Child Neurology, Tepecik Training and Research Hospital, İzmir, Turkey.,Neuromuscular Disease Center, Tepecik Training and Research Hospital, İzmir, Turkey
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Peter Nürnberg
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Cologne Center for Genomics (CCG), University of Cologne and University Hospital Cologne, Cologne, Germany
| | - Sebahattin Cirak
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
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6
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Moreno OM, Sánchez AI, Herreño A, Giraldo G, Suárez F, Prieto JC, Clavijo AS, Olaya M, Vargas Y, Benítez J, Surallés J, Rojas A. Phenotypic Characteristics and Copy Number Variants in a Cohort of Colombian Patients with VACTERL Association. Mol Syndromol 2021; 11:271-283. [PMID: 33505230 DOI: 10.1159/000510910] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/13/2020] [Indexed: 11/19/2022] Open
Abstract
VACTERL association (OMIM 192350) is a heterogeneous clinical condition characterized by congenital structural defects that include at least 3 of the following features: vertebral abnormalities, anal atresia, heart defects, tracheoesophageal fistula, renal malformations, and limb defects. The nonrandom occurrence of these malformations and some familial cases suggest a possible association with genetic factors such as chromosomal alterations, gene mutations, and inherited syndromes such as Fanconi anemia (FA). In this study, the clinical phenotype and its relationship with the presence of chromosomal abnormalities and FA were evaluated in 18 patients with VACTERL association. For this, a G-banded karyotype, array-comparative genomic hybridization, and chromosomal fragility test for FA were performed. All patients (10 female and 8 male) showed a broad clinical spectrum: 13 (72.2%) had vertebral abnormalities, 8 (44.4%) had anal atresia, 14 (77.8%) had heart defects, 8 (44.4%) had esophageal atresia, 10 (55.6%) had renal abnormalities, and 10 (55.6%) had limb defects. Chromosomal abnormalities and FA were ruled out. In 2 cases, the finding of microalterations, namely del(15)(q11.2) and dup(17)(q12), explained the phenotype; in 8 cases, copy number variations were classified as variants of unknown significance and as not yet described in VACTERL. These variants comprise genes related to important cellular functions and embryonic development.
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Affiliation(s)
- Olga M Moreno
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Ana I Sánchez
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia.,Departamento Materno Infantil, Facultad de Ciencias de la Salud, Pontificia Universidad Javeriana, Cali, Colombia.,Centro Médico Imbanaco de Cali, Cali, Colombia
| | - Angélica Herreño
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Gustavo Giraldo
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Fernando Suárez
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia.,Unidad de Genética Medica, Hospital Universitario de San Ignacio, Bogotá, Colombia
| | - Juan Carlos Prieto
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Ana Shaia Clavijo
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Mercedes Olaya
- Servicio de Patología, Hospital Universitario de San Ignacio, Bogotá, Colombia
| | - Yaris Vargas
- Servicio de Pediatría, Neonatología, Hospital Universitario de San Ignacio, Bogotá, Colombia
| | - Javier Benítez
- CNIO: Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
| | - Jordi Surallés
- Departamento de Genética y Microbiología, Universidad Autónoma de Barcelona, Barcelona, Spain
| | - Adriana Rojas
- Instituto de Genética Humana, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, Colombia
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7
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The ties that bind: functional clusters in limb-girdle muscular dystrophy. Skelet Muscle 2020; 10:22. [PMID: 32727611 PMCID: PMC7389686 DOI: 10.1186/s13395-020-00240-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/16/2020] [Indexed: 12/13/2022] Open
Abstract
The limb-girdle muscular dystrophies (LGMDs) are a genetically pleiomorphic class of inherited muscle diseases that are known to share phenotypic features. Selected LGMD genetic subtypes have been studied extensively in affected humans and various animal models. In some cases, these investigations have led to human clinical trials of potential disease-modifying therapies, including gene replacement strategies for individual subtypes using adeno-associated virus (AAV) vectors. The cellular localizations of most proteins associated with LGMD have been determined. However, the functions of these proteins are less uniformly characterized, thus limiting our knowledge of potential common disease mechanisms across subtype boundaries. Correspondingly, broad therapeutic strategies that could each target multiple LGMD subtypes remain less developed. We believe that three major "functional clusters" of subcellular activities relevant to LGMD merit further investigation. The best known of these is the glycosylation modifications associated with the dystroglycan complex. The other two, mechanical signaling and mitochondrial dysfunction, have been studied less systematically but are just as promising with respect to the identification of significant mechanistic subgroups of LGMD. A deeper understanding of these disease pathways could yield a new generation of precision therapies that would each be expected to treat a broader range of LGMD patients than a single subtype, thus expanding the scope of the molecular medicines that may be developed for this complex array of muscular dystrophies.
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8
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Woods JD, Khanlou N, Lee H, Signer R, Shieh P, Chen J, Herzog M, Palmer C, Martinez‐Agosto J, Nelson SF. Myopathy associated with homozygous PYROXD1 pathogenic variants detected by genome sequencing. Neuropathology 2020; 40:302-307. [PMID: 32037607 PMCID: PMC7317439 DOI: 10.1111/neup.12641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/02/2019] [Accepted: 12/11/2019] [Indexed: 12/01/2022]
Abstract
Biallelic pathogenic variants in the gene PYROXD1 have recently been described to cause early-onset autosomal recessive myopathy. Myopathy associated with PYROXD1 pathogenic variants is rare and reported in only 17 individuals. Known pathogenic variants in PYROXD1 include missense, insertion and essential splice-site variants. Here we describe a consanguineous family of individuals affected with late-onset myopathy and homozygous PYROXD1 missense variants (NM_024854.5:c.464A>G [p.Asn155Ser]) expanding our understanding of the possible disease phenotypes of PYROXD1-associated myopathy.
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Affiliation(s)
- Jeremy D. Woods
- Department of PediatricsUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Negar Khanlou
- Department of PathologyUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Hane Lee
- Department of PathologyUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Human GeneticsUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Rebecca Signer
- Department of Human GeneticsUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Perry Shieh
- Department of NeurologyUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Johnathan Chen
- Department of RadiologyUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Matthew Herzog
- Department of Human GeneticsUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | - Christina Palmer
- Department of Human GeneticsUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Psychiatry and Behavioral SciencesUniversity of California Los AngelesLos AngelesCaliforniaUSA
| | | | | | - Stanley F. Nelson
- Department of PediatricsUniversity of California Los AngelesLos AngelesCaliforniaUSA
- Department of Human GeneticsUniversity of California Los AngelesLos AngelesCaliforniaUSA
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9
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Lornage X, Romero NB, Laporte J, Böhm J. [PYROXD1-related myopathy]. Med Sci (Paris) 2019; 35 Hors série n° 2:43-44. [PMID: 31859631 DOI: 10.1051/medsci/2019183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Des mutations récessives dans le gène PYROXD1 ont été récemment décrites chez des patients présentant un tableau de myopathie congénitale ou de dystrophie musculaire des ceintures [1-4]. PYROXD1 (PYRidine nucleotide-disulfide OXidoreductase Domain-containing protein 1) est une protéine exprimée de manière ubiquitaire que l’on retrouve dans le cytosol et les noyaux des fibres musculaires squelettiques. La fonction précise de PYROXD1 est peu connue et des analyses de complémentation dans la levure suggèrent qu’il s’agit d’une oxido-réductase capable de prévenir les effets du stress oxydatif [3]. La diminution de l’expression de PYROXD1 est létale lors du développement chez la drosophile, et elle altère la prolifération, la migration, et la différentiation des myoblastes murins.
Cet article vise à résumer brièvement les caractéristiques cliniques, histologiques, et génétiques de la myopathie liée à PYROXD1 afin d’éclairer le mécanisme pathophysiologique de la maladie et d’analyser la corrélation entre génotype et phénotype.
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Affiliation(s)
| | - Norma B Romero
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Inserm UMRS974, GH Pitié-Salpêtrière, Paris, France
| | | | - Johann Böhm
- IGBMC, Inserm U1258, CNRS UMR7104, Illkirch, France
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Lornage X, Schartner V, Balbueno I, Biancalana V, Willis T, Echaniz-Laguna A, Scheidecker S, Quinlivan R, Fardeau M, Malfatti E, Lannes B, Sewry C, Romero NB, Laporte J, Böhm J. Clinical, histological, and genetic characterization of PYROXD1-related myopathy. Acta Neuropathol Commun 2019; 7:138. [PMID: 31455395 PMCID: PMC6710884 DOI: 10.1186/s40478-019-0781-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/25/2019] [Indexed: 12/28/2022] Open
Abstract
Recessive mutations in PYROXD1, encoding an oxidoreductase, were recently reported in families with congenital myopathy or limb-girdle muscular dystrophy. Here we describe three novel PYROXD1 families at the clinical, histological, and genetic level. Histological analyses on muscle biopsies from all families revealed fiber size variability, endomysial fibrosis, and muscle fibers with multiple internal nuclei and cores. Further characterization of the structural muscle defects uncovered aggregations of myofibrillar proteins, and provided evidence for enhanced oxidative stress. Sequencing identified homozygous or compound heterozygous PYROXD1 mutations including the first deep intronic mutation reinforcing a cryptic donor splice site and resulting in mRNA instability through exonisation of an intronic segment. Overall, this work expands the PYROXD1 mutation spectrum, defines and specifies the histopathological hallmarks of the disorder, and indicates that oxidative stress contributes to the pathomechanism. Comparison of all new and published cases uncovered a genotype/phenotype correlation with a more severe and early-onset phenotypic presentation of patients harboring splice mutations resulting in reduced PYROXD1 protein levels compared with patients carrying missense mutations.
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