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Kang PB, Jorand-Fletcher M, Zhang W, McDermott SW, Berry R, Chambers C, Wong KN, Mohamed Y, Thomas S, Venkatesh YS, Westfield C, Whitehead N, Johnson NE. Genetic Patterns of Selected Muscular Dystrophies in the Muscular Dystrophy Surveillance, Tracking, and Research Network. Neurol Genet 2023; 9:e200113. [PMID: 38045992 PMCID: PMC10692796 DOI: 10.1212/nxg.0000000000200113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/29/2023] [Indexed: 12/05/2023]
Abstract
Background and Objectives To report the genetic etiologies of Emery-Dreifuss muscular dystrophy (EDMD), limb-girdle muscular dystrophy (LGMD), congenital muscular dystrophy (CMD), and distal muscular dystrophy (DD) in 6 geographically defined areas of the United States. Methods This was a cross-sectional, population-based study in which we studied the genes and variants associated with muscular dystrophy in individuals who were diagnosed with and received care for EDMD, LGMD, CMD, and DD from January 1, 2008, through December 31, 2016, in the 6 areas of the United States covered by the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet). Variants of unknown significance (VUSs) from the original genetic test reports were reanalyzed for changes in interpretation. Results Among 243 individuals with definite or probable muscular dystrophy, LGMD was the most common diagnosis (138 cases), followed by CMD (62 cases), DD (22 cases), and EDMD (21 cases). There was a higher proportion of male individuals compared with female individuals, which persisted after excluding X-linked genes (EMD) and autosomal genes reported to have skewed gender ratios (ANO5, CAV3, and LMNA). The most common associated genes were FKRP, CAPN3, ANO5, and DYSF. Reanalysis yielded more definitive variant interpretations for 60 of 144 VUSs, with a mean interval between the original clinical genetic test of 8.11 years for all 144 VUSs and 8.62 years for the 60 reclassified variants. Ten individuals were found to have monoallelic pathogenic variants in genes known to be primarily recessive. Discussion This study is distinct for being an examination of 4 types of muscular dystrophies in selected geographic areas of the United States. The striking proportion of resolved VUSs demonstrates the value of periodic re-examinations of these variants. Such re-examinations will resolve some genetic diagnostic ambiguities before initiating repeat testing or more invasive diagnostic procedures such as muscle biopsy. The presence of monoallelic pathogenic variants in recessive genes in our cohort indicates that some individuals with muscular dystrophy continue to face incomplete genetic diagnoses; further refinements in genetic knowledge and diagnostic approaches will optimize diagnostic information for these individuals.
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Affiliation(s)
- Peter B Kang
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Magali Jorand-Fletcher
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Wanfang Zhang
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Suzanne W McDermott
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Reba Berry
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Chelsea Chambers
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Kristen N Wong
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Yara Mohamed
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Shiny Thomas
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Y Swamy Venkatesh
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Christina Westfield
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Nedra Whitehead
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
| | - Nicholas E Johnson
- From the Paul & Sheila Wellstone Muscular Dystrophy Center (P.B.K.), Department of Neurology, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis; Department of Pediatrics (M.J.-F., Y.M.), University of Florida College of Medicine, Gainesville; Department of Epidemiology and Biostatistics (W.Z.), University of South Carolina, Columbia; Department of Environmental, Occupational, and Geospatial Health Sciences (S.W.M.), Graduate School of Public Health and Health Policy, City University of New York; Division of Population Health Surveillance (R.B., C.W.), Bureau of Maternal and Child Health, South Carolina Department of Health and Environmental Control, Columbia; Department of Human and Molecular Genetics (C.C.), Virginia Commonwealth University, Richmond; Department of Pediatrics (K.N.W.), University of Utah, Salt Lake City; New York State Department of Health (S.T.), Albany; Department of Neurology (Y.S.V.), University of South Carolina, Columbia; RTI International (N.W.), Research Triangle Park, NC; and Department of Neurology (N.E.J.), Virginia Commonwealth University, Richmond
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Rathore G, Kang PB. Pediatric Neuromuscular Diseases. Pediatr Neurol 2023; 149:1-14. [PMID: 37757659 DOI: 10.1016/j.pediatrneurol.2023.08.034] [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: 03/15/2023] [Revised: 07/25/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
The diagnostic and referral workflow for children with neuromuscular disorders is evolving, particularly as newborn screening programs are expanding in tandem with novel therapeutic developments. However, for the children who present with symptoms and signs of potential neuromuscular disorders, anatomic localization, guided initially by careful history and physical examination, continues to be the cardinal initial step in the diagnostic evaluation. It is important to consider whether the localization is more likely to be in the lower motor neuron, peripheral nerve, neuromuscular junction, or muscle. After that, disease etiologies can be divided broadly into inherited versus acquired categories. Considerations of localization and etiologies will help generate a differential diagnosis, which in turn will guide diagnostic testing. Once a diagnosis is made, it is important to be aware of current treatment options, as a number of new therapies for some of these disorders have been approved in recent years. Families are also increasingly interested in clinical research, which may include natural history studies and interventional clinical trials. Such research has proliferated for rare neuromuscular diseases, leading to exciting advances in diagnostic and therapeutic technologies, promising dramatic changes in the landscape of these disorders in the years to come.
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Affiliation(s)
- Geetanjali Rathore
- Division of Neurology, Department of Pediatrics, University of Nebraska College of Medicine, Omaha, Nebraska
| | - Peter B Kang
- Paul and Sheila Wellstone Muscular Dystrophy Center and Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota; Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota.
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3
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Caputo V, Megalizzi D, Fabrizio C, Termine A, Colantoni L, Caltagirone C, Giardina E, Cascella R, Strafella C. Update on the Molecular Aspects and Methods Underlying the Complex Architecture of FSHD. Cells 2022; 11:cells11172687. [PMID: 36078093 PMCID: PMC9454908 DOI: 10.3390/cells11172687] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Despite the knowledge of the main mechanisms involved in facioscapulohumeral muscular dystrophy (FSHD), the high heterogeneity and variable penetrance of the disease complicate the diagnosis, characterization and genotype–phenotype correlation of patients and families, raising the need for further research and data. Thus, the present review provides an update of the main molecular aspects underlying the complex architecture of FSHD, including the genetic factors (related to D4Z4 repeated units and FSHD-associated genes), epigenetic elements (D4Z4 methylation status, non-coding RNAs and high-order chromatin interactions) and gene expression profiles (FSHD transcriptome signatures both at bulk tissue and single-cell level). In addition, the review will also describe the methods currently available for investigating the above-mentioned features and how the resulting data may be combined with artificial-intelligence-based pipelines, with the purpose of developing a multifunctional tool tailored to enhancing the knowledge of disease pathophysiology and progression and fostering the research for novel treatment strategies, as well as clinically useful biomarkers. In conclusion, the present review highlights how FSHD should be regarded as a disease characterized by a molecular spectrum of genetic and epigenetic factors, whose alteration plays a differential role in DUX4 repression and, subsequently, contributes to determining the FSHD phenotype.
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Affiliation(s)
- Valerio Caputo
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
- Department of Biomedicine and Prevention, Tor Vergata University, 00133 Rome, Italy
| | - Domenica Megalizzi
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
- Department of Biomedicine and Prevention, Tor Vergata University, 00133 Rome, Italy
| | - Carlo Fabrizio
- Data Science Unit, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Andrea Termine
- Data Science Unit, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Luca Colantoni
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Carlo Caltagirone
- Department of Clinical and Behavorial Neurology, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Emiliano Giardina
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
- Department of Biomedicine and Prevention, Tor Vergata University, 00133 Rome, Italy
- Correspondence: ; Tel.: +39-0651501550
| | - Raffaella Cascella
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
- Department of Biomedicine and Prevention, Tor Vergata University, 00133 Rome, Italy
| | - Claudia Strafella
- Genomic Medicine Laboratory-UILDM, Santa Lucia Foundation IRCCS, 00179 Rome, Italy
- Department of Biomedicine and Prevention, Tor Vergata University, 00133 Rome, Italy
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4
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Jia FF, Drew AP, Nicholson GA, Corbett A, Kumar KR. Facioscapulohumeral muscular dystrophy type 2: an update on the clinical, genetic, and molecular findings. Neuromuscul Disord 2021; 31:1101-1112. [PMID: 34711481 DOI: 10.1016/j.nmd.2021.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/01/2021] [Accepted: 09/09/2021] [Indexed: 11/25/2022]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a common genetic disease of the skeletal muscle with a characteristic pattern of weakness. Facioscapulohumeral muscular dystrophy type 2 (FSHD2) accounts for approximately 5% of all cases of FSHD and describes patients without a D4Z4 repeat contraction on chromosome 4. Phenotypically FSHD2 shows virtually no difference from FSHD1 and both forms of FSHD arise via a common downstream mechanism of epigenetic derepression of the transcription factor DUX4 in skeletal muscle cells. This results in expression of DUX4 and target genes leading to skeletal muscle toxicity. Over the past decade, major progress has been made in our understanding of the genetic and epigenetic architecture that underlies FSHD2 pathogenesis, as well as the clinical manifestations and disease progression. These include the finding that FSHD2 is a digenic disease and that mutations in the genes SMCHD1, DNMT3B, and more recently LRIF1, can cause FSHD2. FSHD2 is complex and it is important that clinicians keep abreast of recent developments; this review aims to serve as an update of the clinical, genetic, and molecular research into this condition.
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Affiliation(s)
- Fangzhi Frank Jia
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia.
| | - Alexander P Drew
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.
| | - Garth Alexander Nicholson
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
| | - Alastair Corbett
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
| | - Kishore Raj Kumar
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia; Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
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Precise Epigenetic Analysis Using Targeted Bisulfite Genomic Sequencing Distinguishes FSHD1, FSHD2, and Healthy Subjects. Diagnostics (Basel) 2021; 11:diagnostics11081469. [PMID: 34441403 PMCID: PMC8393475 DOI: 10.3390/diagnostics11081469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/01/2021] [Accepted: 08/11/2021] [Indexed: 12/16/2022] Open
Abstract
The true prevalence of facioscapulohumeral muscular dystrophy (FSHD) is unknown due to difficulties with accurate clinical evaluation and the complexities of current genetic diagnostics. Interestingly, all forms of FSHD are linked to epigenetic changes in the chromosome 4q35 D4Z4 macrosatellite, suggesting that epigenetic analysis could provide an avenue for sequence-based FSHD diagnostics. However, studies assessing DNA methylation at the FSHD locus have produced conflicting results; thus, the utility of this technique as an FSHD diagnostic remains controversial. Here, we critically compared two protocols for epigenetic analysis of the FSHD region using bisulfite genomic sequencing: Jones et al., that contends to be individually diagnostic for FSHD1 and FSHD2, and Gaillard et al., that can identify some changes in DNA methylation levels between groups of clinically affected FSHD and healthy subjects, but is not individually diagnostic for any form of FSHD. We performed both sets of assays on the same genetically confirmed samples and showed that this discrepancy was due strictly to differences in amplicon specificity. We propose that the epigenetic status of the FSHD-associated D4Z4 arrays, when accurately assessed, is a diagnostic for genetic FSHD and can readily distinguish between healthy, FSHD1 and FSHD2. Thus, epigenetic diagnosis of FSHD, which can be performed on saliva DNA, will greatly increase accessibility to FSHD diagnostics for populations around the world.
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Nallamilli BRR, Chaubey A, Valencia CA, Stansberry L, Behlmann AM, Ma Z, Mathur A, Shenoy S, Ganapathy V, Jagannathan L, Ramachander V, Ferlini A, Bean L, Hegde M. A single NGS-based assay covering the entire genomic sequence of the DMD gene facilitates diagnostic and newborn screening confirmatory testing. Hum Mutat 2021; 42:626-638. [PMID: 33644936 DOI: 10.1002/humu.24191] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 01/08/2021] [Accepted: 02/09/2021] [Indexed: 01/14/2023]
Abstract
Molecular diagnosis for Duchenne and Becker muscular dystrophies (DMD/BMD) involves a two-tiered approach for detection of deletions/duplications using MLPA or array CGH, followed by sequencing of coding and flanking intronic regions to detect sequence variants, which is time-consuming and expensive. We have developed a comprehensive next-generation sequencing (NGS)-based single-step assay to sequence the entire 2.2 Mb of the DMD gene to detect all copy number and sequence variants in both index males and carrier females. Assay validation was 100% concordant with other methodologies. A total of 772 samples have been tested, of which 62% (N = 480) were index cases with a clinical suspicion of DMD. Carrier testing females account for 38% (N = 292). Molecular diagnosis was confirmed in 86% (N = 413) of the index cases. Intragenic deletions and duplications (single-exon or multi-exon) were detected in 60% (N = 247) and 14% (N = 58) of the index cases, respectively. Full-sequence analysis of the entire gene allows for detection of deep intronic pathogenic variants and accurate breakpoint detection of CNVs involving similar exons, which could have an impact on the outcome of clinical trials. This comprehensive assay is highly sensitive for diagnostic testing for DMD and is also suitable for confirmatory testing for newborn screening for DMD.
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Affiliation(s)
| | - Alka Chaubey
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | - C A Valencia
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | - Leah Stansberry
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | | | - Zeqiang Ma
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | - Abhinav Mathur
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | - Suresh Shenoy
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | | | | | | | - Alessandra Ferlini
- Unit of Medical Genetics, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Lora Bean
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
| | - Madhuri Hegde
- PerkinElmer Genomics, PerkinElmer Inc, Waltham, Massachusetts, USA
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Heier CR, Zhang A, Nguyen NY, Tully CB, Panigrahi A, Gordish-Dressman H, Pandey SN, Guglieri M, Ryan MM, Clemens PR, Thangarajh M, Webster R, Smith EC, Connolly AM, McDonald CM, Karachunski P, Tulinius M, Harper A, Mah JK, Fiorillo AA, Chen YW. Multi-Omics Identifies Circulating miRNA and Protein Biomarkers for Facioscapulohumeral Dystrophy. J Pers Med 2020; 10:jpm10040236. [PMID: 33228131 PMCID: PMC7711540 DOI: 10.3390/jpm10040236] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/15/2022] Open
Abstract
The development of therapeutics for muscle diseases such as facioscapulohumeral dystrophy (FSHD) is impeded by a lack of objective, minimally invasive biomarkers. Here we identify circulating miRNAs and proteins that are dysregulated in early-onset FSHD patients to develop blood-based molecular biomarkers. Plasma samples from clinically characterized individuals with early-onset FSHD provide a discovery group and are compared to healthy control volunteers. Low-density quantitative polymerase chain reaction (PCR)-based arrays identify 19 candidate miRNAs, while mass spectrometry proteomic analysis identifies 13 candidate proteins. Bioinformatic analysis of chromatin immunoprecipitation (ChIP)-seq data shows that the FSHD-dysregulated DUX4 transcription factor binds to regulatory regions of several candidate miRNAs. This panel of miRNAs also shows ChIP signatures consistent with regulation by additional transcription factors which are up-regulated in FSHD (FOS, EGR1, MYC, and YY1). Validation studies in a separate group of patients with FSHD show consistent up-regulation of miR-100, miR-103, miR-146b, miR-29b, miR-34a, miR-454, miR-505, and miR-576. An increase in the expression of S100A8 protein, an inflammatory regulatory factor and subunit of calprotectin, is validated by Enzyme-Linked Immunosorbent Assay (ELISA). Bioinformatic analyses of proteomics and miRNA data further support a model of calprotectin and toll-like receptor 4 (TLR4) pathway dysregulation in FSHD. Moving forward, this panel of miRNAs, along with S100A8 and calprotectin, merit further investigation as monitoring and pharmacodynamic biomarkers for FSHD.
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Affiliation(s)
- Christopher R. Heier
- Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA; (H.G.-D.); (A.A.F.)
- Correspondence: (C.R.H.); (Y.-W.C.)
| | - Aiping Zhang
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Nhu Y Nguyen
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Christopher B. Tully
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Aswini Panigrahi
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Heather Gordish-Dressman
- Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA; (H.G.-D.); (A.A.F.)
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Sachchida Nand Pandey
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | | | - Monique M. Ryan
- The Royal Children’s Hospital, Melbourne University, Parkville, Victoria 3052, Australia;
| | - Paula R. Clemens
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA;
| | - Mathula Thangarajh
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA;
| | | | - Edward C. Smith
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27705, USA;
| | - Anne M. Connolly
- Nationwide Children’s Hospital, The Ohio State University, Columbus, OH 43205, USA;
| | - Craig M. McDonald
- Department of Physical Medicine and Rehabilitation, University of California at Davis Medical Center, Sacramento, CA 95817, USA;
| | - Peter Karachunski
- Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Mar Tulinius
- Department of Pediatrics, Gothenburg University, Queen Silvia Children’s Hospital, 41685 Göteborg, Sweden;
| | - Amy Harper
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | - Jean K. Mah
- Deparment of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, T2N T3B, Calgary, AB 6A81N4, Canada;
| | - Alyson A. Fiorillo
- Department of Genomics and Precision Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA; (H.G.-D.); (A.A.F.)
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
| | - Yi-Wen Chen
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA; (A.Z.); (N.Y.N.); (C.B.T.); (A.P.); (S.N.P.)
- Correspondence: (C.R.H.); (Y.-W.C.)
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8
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Goossens R, van den Boogaard ML, Lemmers RJLF, Balog J, van der Vliet PJ, Willemsen IM, Schouten J, Maggio I, van der Stoep N, Hoeben RC, Tapscott SJ, Geijsen N, Gonçalves MAFV, Sacconi S, Tawil R, van der Maarel SM. Intronic SMCHD1 variants in FSHD: testing the potential for CRISPR-Cas9 genome editing. J Med Genet 2019; 56:828-837. [PMID: 31676591 DOI: 10.1136/jmedgenet-2019-106402] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/04/2019] [Accepted: 09/21/2019] [Indexed: 01/14/2023]
Abstract
BACKGROUND Facioscapulohumeral dystrophy (FSHD) is associated with partial chromatin relaxation of the DUX4 retrogene containing D4Z4 macrosatellite repeats on chromosome 4, and transcriptional de-repression of DUX4 in skeletal muscle. The common form of FSHD, FSHD1, is caused by a D4Z4 repeat array contraction. The less common form, FSHD2, is generally caused by heterozygous variants in SMCHD1. METHODS We employed whole exome sequencing combined with Sanger sequencing to screen uncharacterised FSHD2 patients for extra-exonic SMCHD1 mutations. We also used CRISPR-Cas9 genome editing to repair a pathogenic intronic SMCHD1 variant from patient myoblasts. RESULTS We identified intronic SMCHD1 variants in two FSHD families. In the first family, an intronic variant resulted in partial intron retention and inclusion of the distal 14 nucleotides of intron 13 into the transcript. In the second family, a deep intronic variant in intron 34 resulted in exonisation of 53 nucleotides of intron 34. In both families, the aberrant transcripts are predicted to be non-functional. Deleting the pseudo-exon by CRISPR-Cas9 mediated genome editing in primary and immortalised myoblasts from the index case of the second family restored wild-type SMCHD1 expression to a level that resulted in efficient suppression of DUX4. CONCLUSIONS The estimated intronic mutation frequency of almost 2% in FSHD2, as exemplified by the two novel intronic SMCHD1 variants identified here, emphasises the importance of screening for intronic variants in SMCHD1. Furthermore, the efficient suppression of DUX4 after restoring SMCHD1 levels by genome editing of the mutant allele provides further guidance for therapeutic strategies.
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Affiliation(s)
- Remko Goossens
- Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Judit Balog
- Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Iris M Willemsen
- Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Julie Schouten
- Hubrecht Institute-KNAW and University Medical Center, Utrecht, The Netherlands.,Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht, The Netherlands
| | - Ignazio Maggio
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Nienke van der Stoep
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Rob C Hoeben
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Stephen J Tapscott
- Division of Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Niels Geijsen
- Hubrecht Institute-KNAW and University Medical Center, Utrecht, The Netherlands.,Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht, The Netherlands
| | - Manuel A F V Gonçalves
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sabrina Sacconi
- Peripheral Nervous System, Muscle and ALS Department, Université Côte d'Azur, Nice, France.,Institute for Research on Cancer and Aging of Nice, Faculty of Medicine, Université Côte d'Azur, Nice, France
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
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9
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Abstract
Facioscapulohumeral muscular dystrophy (FSHD), a progressive myopathy that afflicts individuals of all ages, provides a powerful model of the complex interplay between genetic and epigenetic mechanisms of chromatin regulation. FSHD is caused by dysregulation of a macrosatellite repeat, either by contraction of the repeat or by mutations in silencing proteins. Both cases lead to chromatin relaxation and, in the context of a permissive allele, aberrant expression of the DUX4 gene in skeletal muscle. DUX4 is a pioneer transcription factor that activates a program of gene expression during early human development, after which its expression is silenced in most somatic cells. When misexpressed in FSHD skeletal muscle, the DUX4 program leads to accumulated muscle pathology. Epigenetic regulators of the disease locus represent particularly attractive therapeutic targets for FSHD, as many are not global modifiers of the genome, and altering their expression or activity should allow correction of the underlying defect.
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MESH Headings
- CRISPR-Cas Systems
- Chromatin/chemistry
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosomes, Human, Pair 4
- DNA (Cytosine-5-)-Methyltransferases/genetics
- DNA (Cytosine-5-)-Methyltransferases/metabolism
- DNA Methylation
- Epigenesis, Genetic
- Gene Editing
- Genetic Loci
- Genome, Human
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Facioscapulohumeral/classification
- Muscular Dystrophy, Facioscapulohumeral/genetics
- Muscular Dystrophy, Facioscapulohumeral/metabolism
- Muscular Dystrophy, Facioscapulohumeral/pathology
- Mutation
- Severity of Illness Index
- DNA Methyltransferase 3B
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Affiliation(s)
- Charis L Himeda
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Nevada 89557, USA;
| | - Peter L Jones
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Nevada 89557, USA;
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10
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Lemmers RJLF, van der Stoep N, Vliet PJVD, Moore SA, San Leon Granado D, Johnson K, Topf A, Straub V, Evangelista T, Mozaffar T, Kimonis V, Shaw ND, Selvatici R, Ferlini A, Voermans N, van Engelen B, Sacconi S, Tawil R, Lamers M, van der Maarel SM. SMCHD1 mutation spectrum for facioscapulohumeral muscular dystrophy type 2 (FSHD2) and Bosma arhinia microphthalmia syndrome (BAMS) reveals disease-specific localisation of variants in the ATPase domain. J Med Genet 2019; 56:693-700. [PMID: 31243061 DOI: 10.1136/jmedgenet-2019-106168] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/11/2019] [Accepted: 05/15/2019] [Indexed: 01/15/2023]
Abstract
BACKGROUND Variants in the Structural Maintenance of Chromosomes flexible Hinge Domain-containing protein 1 (SMCHD1) can cause facioscapulohumeral muscular dystrophy type 2 (FSHD2) and the unrelated Bosma arhinia microphthalmia syndrome (BAMS). In FSHD2, pathogenic variants are found anywhere in SMCHD1 while in BAMS, pathogenic variants are restricted to the extended ATPase domain. Irrespective of the phenotypic outcome, both FSHD2-associated and BAMS-associated SMCHD1 variants result in quantifiable local DNA hypomethylation. We compared FSHD2, BAMS and non-pathogenic SMCHD1 variants to derive genotype-phenotype relationships. METHODS Examination of SMCHD1 variants and methylation of the SMCHD1-sensitive FSHD locus DUX4 in 187 FSHD2 families, 41 patients with BAMS and in control individuals. Analysis of variants in a three-dimensional model of the ATPase domain of SMCHD1. RESULTS DUX4 methylation analysis is essential to establish pathogenicity of SMCHD1 variants. Although the FSHD2 mutation spectrum includes all types of variants covering the entire SMCHD1 locus, missense variants are significantly enriched in the extended ATPase domain. Identification of recurrent variants suggests disease-specific residues for FSHD2 and in BAMS, consistent with a largely disease-specific localisation of variants in SMCHD1. CONCLUSIONS The localisation of missense variants within the ATPase domain of SMCHD1 may contribute to the differences in phenotypic outcome.
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Affiliation(s)
| | - Nienke van der Stoep
- Department of Clinical Genetics, Laboratory for Diagnostic Genome Analysis, Leids Universitair Medisch Centrum, Leiden, The Netherlands
| | | | - Steven A Moore
- Department of Pathology, University of Iowa, Iowa City, Iowa, USA
| | | | - Katherine Johnson
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | - Ana Topf
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | | | - Tahseen Mozaffar
- Department of Neurology, University of California Irvine, Irvine, California, USA
| | - Virginia Kimonis
- Department of Pediatrics, University of California, Irvine, Irvine, California, USA
| | | | - Rita Selvatici
- Department of Medical Sciences; Medical Genetics Unit, University of Ferrara, Ferrara, Italy
| | - Alessandra Ferlini
- Dipartimento di Medicina Sperimentale e Diagnostica, Università di Ferrara, Ferrara, Italy
| | - Nicol Voermans
- Department of Neurology, Radboudumc, Nijmegen, Gelderland, The Netherlands
| | - Baziel van Engelen
- Department of Neurology, Radboudumc, Nijmegen, Gelderland, The Netherlands
| | - Sabrina Sacconi
- Centre de Référence Maladies Neuromusculaires, Hôpital Archet, Nice, France
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Meindert Lamers
- Department of Cell and Chemical Biology, Leiden Universitair Medisch Centrum, Leiden, The Netherlands
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11
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Cascella R, Strafella C, Caputo V, Galota RM, Errichiello V, Scutifero M, Petillo R, Marella GL, Arcangeli M, Colantoni L, Zampatti S, Ricci E, Deidda G, Politano L, Giardina E. Digenic Inheritance of Shortened Repeat Units of the D4Z4 Region and a Loss-of-Function Variant in SMCHD1 in a Family With FSHD. Front Neurol 2018; 9:1027. [PMID: 30546343 PMCID: PMC6279899 DOI: 10.3389/fneur.2018.01027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/14/2018] [Indexed: 11/24/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a neuromuscular disorder which is typically transmitted by an autosomal dominant pattern, although reduced penetrance and sporadic cases caused by de novo mutations, are often observed. FSHD may be caused by a contraction of a repetitive element, located on chromosome 4 (4q35). This locus is named D4Z4 and consists of 11 to more than 100 repeated units (RU). The D4Z4 is normally hypermethylated and the genes located on this locus are silenced. In case of FSHD, the D4Z4 region is characterized by 1–10 repeats and results in the region being hypomethylated. However, 5% of FSHD cases do not carry the short allele of D4Z4 region. To date, two forms of FSHD (FSHD1 and FSHD2) are known. FSHD2 is usually observed in patients without the D4Z4 fragment contraction and carrying variants in SMCHD1 (18p11.32) gene. We report the case of a young adult patient who shows severe symptoms of FSHD. Preliminary genetic analysis did not clarify the phenotype, therefore we decided to study the family members by genetic and epigenetic approaches. The analysis of D4Z4 fragment resulted to be 8 RU in the affected proband and in his father; 26 RU in the mother and 25 RU in the maternal uncle. SMCHD1 analysis revealed a heterozygous variation within the exon 41. The variant was detected in the proband, her mother and the uncle. Furthermore, epigenetic analysis of CpG6 methylation regions showed significant hypomethylation in the affected patient (54%) and in the mother (56%), in contrast to the father (88%) and the uncle (81%) carrying higher methylation levels. The analysis of DR1 methylation levels reported hypomethylation for the proband (19%), the mother (11%), and the uncle (16%). The father showed normal DR1 methylation levels (>30%). Given these results, the combined inheritance of SMCHD1 variant and the short fragment might explain the severe FSHD phenotype displayed by the proband. On this subject, SMCHD1 analysis should be promoted in a larger number of patients, even in presence of D4Z4 contractions, to facilitate the genotype-phenotype correlation as well as, to enable a more precise diagnosis and prognosis of the disease.
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Affiliation(s)
- Raffaella Cascella
- Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy.,Department of Chemical-Toxicological and Pharmacological Evaluation of Drugs, Catholic University Our Lady of Good Counsel, Tirana, Albania
| | - Claudia Strafella
- Department of Biomedicine and Prevention Tor Vergata University, Rome, Italy.,Emotest Laboratory, Pozzuoli, Italy
| | - Valerio Caputo
- Department of Biomedicine and Prevention Tor Vergata University, Rome, Italy
| | | | - Valeria Errichiello
- Department of Biomedicine and Prevention Tor Vergata University, Rome, Italy
| | - Marianna Scutifero
- Department of Experimental Medicine, Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Roberta Petillo
- Department of Experimental Medicine, Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Gian Luca Marella
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
| | - Mauro Arcangeli
- Department of Biomedicine and Prevention Tor Vergata University, Rome, Italy
| | - Luca Colantoni
- Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | - Stefania Zampatti
- Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy
| | - Enzo Ricci
- Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy
| | - Giancarlo Deidda
- Institute of Cell Biology and Neurobiology, National Research Council of Italy, Monterotondo, Rome, Italy
| | - Luisa Politano
- Department of Experimental Medicine, Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Emiliano Giardina
- Molecular Genetics Laboratory UILDM, Santa Lucia Foundation, Rome, Italy.,Department of Biomedicine and Prevention Tor Vergata University, Rome, Italy
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12
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Renard D, Taieb G, Garibaldi M, Maues De Paula A, Bernard R, Lagha N, Cristofari G, Vovan C, Chaix C, Lévy N, Khau Van Kien P, Sacconi S. Inflammatory facioscapulohumeral muscular dystrophy type 2 in 18p deletion syndrome. Am J Med Genet A 2018; 176:1760-1763. [PMID: 30055030 DOI: 10.1002/ajmg.a.38843] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 03/30/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) has been shown to be related to genetic and epigenetic derepression of DUX4 (mapping to chromosome 4), a gene located within a repeat array of D4Z4 sequences of polymorphic length. FSHD type 1 (FSHD1) is associated with pathogenic D4Z4 repeat array contraction, while FSHD type 2 (FSHD2) is associated with SMCHD1 variants (a chromatin modifier gene that maps to the short arm of chromosome 18). Both FSHD types require permissive polyadenylation signal (4qA) downstream of the D4Z4 array.
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Affiliation(s)
- Dimitri Renard
- Department of Neurology, CHU Nîmes, Hôpital Caremeau, Nîmes, France
| | - Guillaume Taieb
- Department of Neurology, CHU Nîmes, Hôpital Caremeau, Nîmes, France
| | - Matteo Garibaldi
- Peripheral Nervous System, Muscle and ALS Department, Nice University Hospital, Université Côte d'Azur, Nice, France.,Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Andre Maues De Paula
- Neuropathology Laboratory, Faculty of Medicine of Marseille, Assistance Publique-Hôpitaux de Marseille, La Timone Hospital, Marseille, France
| | - Rafaelle Bernard
- Medical Genetic Department, Assistance Publique-Hôpitaux de Marseille, La Timone Hospital; Aix-Marseille University, Marseille, France.,INSERM GMGF UMR_S910, Marseille, France
| | - Nadira Lagha
- Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081, CNRS UMR 7284, Université Côte d'Azur (UCA), Nice, France
| | - Gael Cristofari
- Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081, CNRS UMR 7284, Université Côte d'Azur (UCA), Nice, France.,University Hospital Federation (FHU) OncoAge, CHU-Nice, University of Nice Sophia Antipolis, Nice, France
| | - Catherine Vovan
- Medical Genetic Department, Assistance Publique-Hôpitaux de Marseille, La Timone Hospital; Aix-Marseille University, Marseille, France
| | - Charlène Chaix
- Medical Genetic Department, Assistance Publique-Hôpitaux de Marseille, La Timone Hospital; Aix-Marseille University, Marseille, France
| | - Nicolas Lévy
- Medical Genetic Department, Assistance Publique-Hôpitaux de Marseille, La Timone Hospital; Aix-Marseille University, Marseille, France.,INSERM GMGF UMR_S910, Marseille, France
| | | | - Sabrina Sacconi
- Peripheral Nervous System, Muscle and ALS Department, Nice University Hospital, Université Côte d'Azur, Nice, France.,Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081, CNRS UMR 7284, Université Côte d'Azur (UCA), Nice, France
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13
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Chakravorty S, Hegde M. Inferring the effect of genomic variation in the new era of genomics. Hum Mutat 2018; 39:756-773. [PMID: 29633501 DOI: 10.1002/humu.23427] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/20/2018] [Accepted: 03/28/2018] [Indexed: 12/11/2022]
Abstract
Accurate and detailed understanding of the effects of variants in the coding and noncoding regions of the genome is the next big challenge in the new genomic era of personalized medicine, especially to tackle newer findings of genetic and phenotypic heterogeneity of diseases. This is necessary to resolve the gene-variant-disease relationship, the pathogenic variant spectrum of genes, pathogenic variants with variable clinical consequences, and multiloci diseases. In turn, this will facilitate patient recruitment for relevant clinical trials. In this review, we describe the trends in research at the intersection of basic and clinical genomics aiming to (a) overcome molecular diagnostic challenges and increase the clinical utility of next-generation sequencing (NGS) platforms, (b) elucidate variants associated with disease, (c) determine overall genomic complexity including epistasis, complex inheritance patterns such as "synergistic heterozygosity," digenic/multigenic inheritance, modifier effect, and rare variant load. We describe the newly emerging field of integrated functional genomics, in vivo or in vitro large-scale functional approaches, statistical bioinformatics algorithms that support NGS genomics data to interpret variants for timely clinical diagnostics and disease management. Thus, facilitating the discovery of new therapeutic or biomarker options, and their roles in the future of personalized medicine.
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Affiliation(s)
- Samya Chakravorty
- Department of Human Genetics, Emory University School of Medicine, Whitehead Biomedical Research Building Suite 301, Atlanta, Georgia
| | - Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine, Whitehead Biomedical Research Building Suite 301, Atlanta, Georgia
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14
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Integrating clinical and genetic observations in facioscapulohumeral muscular dystrophy. Curr Opin Neurol 2018; 29:606-13. [PMID: 27389814 DOI: 10.1097/wco.0000000000000360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE OF REVIEW This review gives an overview of the currently known key clinical and (epi)genetic aspects of facioscapulohumeral muscular dystrophy (FSHD) and provides perspectives to facilitate future research. RECENT FINDINGS Clinically, imaging studies have contributed to a detailed characterization of the FSHD phenotype, and a model is proposed with five stages of disease progression. A number of clinical trials have been conducted regarding exercise and diet aiming to reduce symptoms. Genetically, at least two different mechanisms (FSHD1 and FSHD2) lead to double homeobox 4 (DUX4) expression in skeletal myocytes, which is expected to be necessary for the disease. Disease severity is most likely determined by a combination of the D4Z4 repeat size and its epigenetic state. SUMMARY FSHD is one of the most common muscular dystrophies and is characterized by a typical distribution of muscle weakness. Progress has been made on clinical as well as on (epi)genetic aspects of the disease. Currently, there is no cure available for FSHD. For successful development of new treatments targeting the disease process, integration of clinical and pathogenetic knowledge is essential. A clinical trial toolbox that consists of patient registries, biomarkers and clinical outcome measures will be required to effectively conduct future clinical trials.
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15
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DeSimone AM, Pakula A, Lek A, Emerson CP. Facioscapulohumeral Muscular Dystrophy. Compr Physiol 2017; 7:1229-1279. [PMID: 28915324 DOI: 10.1002/cphy.c160039] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Facioscapulohumeral Muscular Dystrophy is a common form of muscular dystrophy that presents clinically with progressive weakness of the facial, scapular, and humeral muscles, with later involvement of the trunk and lower extremities. While typically inherited as autosomal dominant, facioscapulohumeral muscular dystrophy (FSHD) has a complex genetic and epigenetic etiology that has only recently been well described. The most prevalent form of the disease, FSHD1, is associated with the contraction of the D4Z4 microsatellite repeat array located on a permissive 4qA chromosome. D4Z4 contraction allows epigenetic derepression of the array, and possibly the surrounding 4q35 region, allowing misexpression of the toxic DUX4 transcription factor encoded within the terminal D4Z4 repeat in skeletal muscles. The less common form of the disease, FSHD2, results from haploinsufficiency of the SMCHD1 gene in individuals carrying a permissive 4qA allele, also leading to the derepression of DUX4, further supporting a central role for DUX4. How DUX4 misexpression contributes to FSHD muscle pathology is a major focus of current investigation. Misexpression of other genes at the 4q35 locus, including FRG1 and FAT1, and unlinked genes, such as SMCHD1, has also been implicated as disease modifiers, leading to several competing disease models. In this review, we describe recent advances in understanding the pathophysiology of FSHD, including the application of MRI as a research and diagnostic tool, the genetic and epigenetic disruptions associated with the disease, and the molecular basis of FSHD. We discuss how these advances are leading to the emergence of new approaches to enable development of FSHD therapeutics. © 2017 American Physiological Society. Compr Physiol 7:1229-1279, 2017.
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Affiliation(s)
- Alec M DeSimone
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Anna Pakula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA
| | - Angela Lek
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Charles P Emerson
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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16
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The sensitivity of exome sequencing in identifying pathogenic mutations for LGMD in the United States. J Hum Genet 2016; 62:243-252. [PMID: 27708273 PMCID: PMC5266644 DOI: 10.1038/jhg.2016.116] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 08/31/2016] [Accepted: 09/02/2016] [Indexed: 01/12/2023]
Abstract
The current study characterizes a cohort of limb-girdle muscular dystrophy (LGMD) in the United States using whole exome sequencing. Fifty-five families affected by LGMD were recruited using an institutionally-approved protocol. Exome sequencing was performed on probands and selected parental samples. Pathogenic mutations and co-segregation patterns were confirmed by Sanger sequencing. Twenty-two families (40%) had novel and previously reported pathogenic mutations, primarily in LGMD genes, but also in genes for Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, congenital myopathy, myofibrillar myopathy, inclusion body myopathy, and Pompe disease. One family was diagnosed via clinical testing. Dominant mutations were identified in COL6A1, COL6A3, FLNC, LMNA, RYR1, SMCHD1, and VCP, recessive mutations in ANO5, CAPN3, GAA, LAMA2, SGCA, and SGCG, and X-linked mutations in DMD. A previously reported variant in DMD was confirmed to be benign. Exome sequencing is a powerful diagnostic tool for LGMD. Despite careful phenotypic screening, pathogenic mutations were found in other muscle disease genes, largely accounting for the increased sensitivity of exome sequencing. Our experience suggests that broad sequencing panels are useful for these analyses due to the phenotypic overlap of many neuromuscular conditions. The confirmation of a benign DMD variant illustrates the potential of exome sequencing to help determine pathogenicity.
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Gaillard MC, Puppo F, Roche S, Dion C, Campana ES, Mariot V, Chaix C, Vovan C, Mazaleyrat K, Tasmadjian A, Bernard R, Dumonceaux J, Attarian S, Lévy N, Nguyen K, Magdinier F, Bartoli M. Segregation between SMCHD1 mutation, D4Z4 hypomethylation and Facio-Scapulo-Humeral Dystrophy: a case report. BMC MEDICAL GENETICS 2016; 17:66. [PMID: 27634379 PMCID: PMC5025538 DOI: 10.1186/s12881-016-0328-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 09/09/2016] [Indexed: 12/22/2022]
Abstract
Background The main form of Facio-Scapulo-Humeral muscular Dystrophy is linked to copy number reduction of the 4q D4Z4 macrosatellite (FSHD1). In 5 % of cases, FSHD phenotype appears in the absence of D4Z4 reduction (FSHD2). In 70-80 % of these patients, variants of the SMCHD1 gene segregate with 4qA haplotypes and D4Z4 hypomethylation. Case presentation We report a family presenting with neuromuscular symptoms reminiscent of FSHD but without D4Z4 copy reduction. We characterized the 4q35 region using molecular combing, searched for mutation in the SMCHD1 gene and determined D4Z4 methylation level by sodium bisulfite sequencing. We further investigated the impact of the SMCHD1 mutation at the protein level and on the NMD-dependent degradation of transcript. In muscle, we observe moderate but significant reduction in D4Z4 methylation, not correlated with DUX4-fl expression. Exome sequencing revealed a heterozygous insertion of 7 bp in exon 37 of the SMCHD1 gene producing a loss of frame with premature stop codon 4 amino acids after the insertion (c.4614-4615insTATAATA). Both wild-type and mutated transcripts are detected. Conclusion The truncated protein is absent and the full-length protein level is similar in patients and controls indicating that in this family, FSHD is not associated with SMCHD1 haploinsufficiency. Electronic supplementary material The online version of this article (doi:10.1186/s12881-016-0328-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Camille Dion
- Aix Marseille Univ, INSERM, GMGF, Marseille, France
| | - Emmanuelle Salort Campana
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Centre de Référence des Maladies Neuromusculaires et de la SLA, Hôpital de la Timone, Marseille, 13385, France
| | - Virginie Mariot
- Center of Research in Myology/ Institut de Myologie UMR974 - UPMC Université Paris 6/ Inserm /FRE3617- CNRS, Groupement Hospitalier de la Pitié Salpétrière, Paris, Cedex 13, France
| | - Charlene Chaix
- APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
| | - Catherine Vovan
- APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
| | | | | | - Rafaelle Bernard
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
| | - Julie Dumonceaux
- Center of Research in Myology/ Institut de Myologie UMR974 - UPMC Université Paris 6/ Inserm /FRE3617- CNRS, Groupement Hospitalier de la Pitié Salpétrière, Paris, Cedex 13, France
| | - Shahram Attarian
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Centre de Référence des Maladies Neuromusculaires et de la SLA, Hôpital de la Timone, Marseille, 13385, France
| | - Nicolas Lévy
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
| | - Karine Nguyen
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
| | | | - Marc Bartoli
- Aix Marseille Univ, INSERM, GMGF, Marseille, France.,APHM, Laboratoire de Génétique Médicale, Hôpital de la Timone, Marseille, 13385, France
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Himeda CL, Jones TI, Jones PL. CRISPR/dCas9-mediated Transcriptional Inhibition Ameliorates the Epigenetic Dysregulation at D4Z4 and Represses DUX4-fl in FSH Muscular Dystrophy. Mol Ther 2016; 24:527-35. [PMID: 26527377 PMCID: PMC4786914 DOI: 10.1038/mt.2015.200] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/21/2015] [Indexed: 12/16/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is one of the most prevalent myopathies, affecting males and females of all ages. Both forms of the disease are linked by epigenetic derepression of the D4Z4 macrosatellite repeat array at chromosome 4q35, leading to aberrant expression of D4Z4-encoded RNAs in skeletal muscle. Production of full-length DUX4 (DUX4-fl) mRNA from the derepressed D4Z4 array results in misexpression of DUX4-FL protein and its transcriptional targets, and apoptosis, ultimately leading to accumulated muscle pathology. Returning the chromatin at the FSHD locus to its nonpathogenic, epigenetically repressed state would simultaneously affect all D4Z4 RNAs, inhibiting downstream pathogenic pathways, and is thus an attractive therapeutic strategy. Advances in CRISPR/Cas9-based genome editing make it possible to target epigenetic modifiers to an endogenous disease locus, although reports to date have focused on more typical genomic regions. Here, we demonstrate that a CRISPR/dCas9 transcriptional inhibitor can be specifically targeted to the highly repetitive FSHD macrosatellite array and alter the chromatin to repress expression of DUX4-fl in primary FSHD myocytes. These results implicate the promoter and exon 1 of DUX4 as potential therapeutic targets and demonstrate the utility of CRISPR technology for correction of the epigenetic dysregulation in FSHD.
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Affiliation(s)
- Charis L Himeda
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Takako I Jones
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Peter L Jones
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
- The Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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19
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The hinge domain of the epigenetic repressor Smchd1 adopts an unconventional homodimeric configuration. Biochem J 2016; 473:733-42. [PMID: 26733688 DOI: 10.1042/bj20151049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/04/2016] [Indexed: 12/18/2022]
Abstract
The structural maintenance of chromosomes (SMC) proteins are fundamental to chromosome organization. They share a characteristic domain structure, featuring a central SMC hinge domain that is critical for forming SMC dimers and interacting with nucleic acids. The structural maintenance of chromosomes flexible hinge domain containing 1 (Smchd1) is a non-canonical member of the SMC family. Although it has been well established that Smchd1 serves crucial roles in epigenetic silencing events implicated in development and disease, much less is known about the structure and function of the Smchd1 protein. Recently, we demonstrated that the C-terminal hinge domain of Smchd1 forms a nucleic acid-binding homodimer; however, it is unclear how the protomers are assembled within the hinge homodimer and how the full-length Smchd1 protein is organized with respect to the hinge region. In the present study, by employing SAXS we demonstrate that the hinge domain of Smchd1 probably adopts an unconventional homodimeric arrangement augmented by an intermolecular coiled coil formed between the two monomers. Such a dimeric structure differs markedly from that of archetypical SMC proteins, raising the possibility that Smchd1 binds chromatin in an unconventional manner.
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20
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Molecular combing compared to Southern blot for measuring D4Z4 contractions in FSHD. Neuromuscul Disord 2015; 25:945-51. [PMID: 26420234 DOI: 10.1016/j.nmd.2015.08.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 11/21/2022]
Abstract
We compare molecular combing to Southern blot in the analysis of the facioscapulohumeral muscular dystrophy type 1 locus (FSHD1) on chromosome 4q35-qter (chr 4q) in genomic DNA specimens sent to a clinical laboratory for FSHD testing. A de-identified set of 87 genomic DNA specimens determined by Southern blot as normal (n = 71), abnormal with D4Z4 macrosatellite repeat array contractions (n = 7), indeterminate (n = 6), borderline (n = 2), or mosaic (n = 1) was independently re-analyzed by molecular combing in a blinded fashion. The molecular combing results were identical to the Southern blot results in 75 (86%) of cases. All contractions (n = 7) and mosaics (n = 1) detected by Southern blot were confirmed by molecular combing. Of the 71 samples with normal Southern blot results, 67 (94%) had concordant molecular combing results. The four discrepancies were either mosaic (n = 2), rearranged (n = 1), or borderline by molecular combing (n = 1). All indeterminate Southern blot results (n = 6) were resolved by molecular combing as either normal (n = 4), borderline (n = 1), or rearranged (n = 1). The two borderline Southern blot results showed a D4Z4 contraction on the chr 4qA allele and a normal result by molecular combing. Molecular combing overcomes a number of technical limitations of Southern blot by providing direct visualization of D4Z4 macrosatellite repeat arrays on specific chr 4q and chr 10q alleles and more precise D4Z4 repeat sizing. This study suggests that molecular combing has superior analytical validity compared to Southern blot for determining D4Z4 contraction size, detecting mosaicism, and resolving borderline and indeterminate Southern blot results. Further studies are needed to establish the clinical validity and diagnostic accuracy of these findings in FSHD.
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21
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Daxinger L, Tapscott SJ, van der Maarel SM. Genetic and epigenetic contributors to FSHD. Curr Opin Genet Dev 2015; 33:56-61. [PMID: 26356006 PMCID: PMC4674299 DOI: 10.1016/j.gde.2015.08.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 08/08/2015] [Accepted: 08/21/2015] [Indexed: 11/28/2022]
Abstract
Facioscapulohumeral dystrophy (FSHD) is an autosomal dominant muscle disorder characterized by distinct chromatin changes including DNA hypomethylation of the D4Z4 macrosatellite repeat array on a disease-permissive 4qA allele and aberrant expression of the D4Z4-embedded DUX4 retrogene in skeletal muscle. Insufficient epigenetic repression of the D4Z4 repeat is the result of at least two different genetic mechanisms leading to two forms of disease, FSHD1 and FSHD2. In the case of FSHD1, a contraction of the D4Z4 repeat array is disease causing whereas FSHD2 is most often caused by mutations in the structural maintenance of chromosomes hinge domain 1 (SMCHD1) gene. Recent studies indicate that a combination of genetic and epigenetic factors that act on the D4Z4 repeat array determine the probability of DUX4 expression in skeletal muscle and disease penetrance and progression.
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Affiliation(s)
- Lucia Daxinger
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stephen J Tapscott
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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22
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Hewitt JE. Loss of epigenetic silencing of the DUX4 transcription factor gene in facioscapulohumeral muscular dystrophy. Hum Mol Genet 2015; 24:R17-23. [PMID: 26113644 DOI: 10.1093/hmg/ddv237] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 06/18/2015] [Indexed: 02/07/2023] Open
Abstract
Current genetic and molecular evidence best supports an epigenetic mechanism for facioscapulohumeral muscular dystrophy (FSHD), whereby de-repression of the D4Z4 macrosatellite array leads to aberrant expression of the DUX4 transcription factor in skeletal muscle. This de-repression is triggered by either array contraction or (more rarely) by mutation of the SMCHD1 (structural maintenance of chromosomes flexible hinge domain containing 1) gene. Activation of DUX4 targets, including germline genes and several mammalian retrotransposons, then drives pathogenesis. A direct role for DUX4 mRNA in suppression of nonsense-mediated decay pathways has recently been demonstrated and may also contribute to muscle pathology. Loss of D4Z4 repression in FSHD is observed as hypomethylation of the array accompanied by loss of repressive chromatin marks. The molecular mechanisms of D4Z4 repression are poorly understood, but recent data have identified an Argonaute (AGO)-dependent siRNA pathway. Targeting this pathway by exogenous siRNAs could be a therapeutic strategy for FSHD.
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Affiliation(s)
- Jane E Hewitt
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
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23
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Jones TI, King OD, Himeda CL, Homma S, Chen JCJ, Beermann ML, Yan C, Emerson CP, Miller JB, Wagner KR, Jones PL. Individual epigenetic status of the pathogenic D4Z4 macrosatellite correlates with disease in facioscapulohumeral muscular dystrophy. Clin Epigenetics 2015; 7:37. [PMID: 25904990 PMCID: PMC4405830 DOI: 10.1186/s13148-015-0072-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 03/11/2015] [Indexed: 12/27/2022] Open
Abstract
Background Both forms of facioscapulohumeral muscular dystrophy (FSHD) are associated with aberrant epigenetic regulation of the chromosome 4q35 D4Z4 macrosatellite. Chromatin changes due to large deletions of heterochromatin (FSHD1) or mutations in chromatin regulatory proteins (FSHD2) lead to relaxation of epigenetic repression and increased expression of the deleterious double homeobox 4 (DUX4) gene encoded within the distal D4Z4 repeat. However, many individuals with the genetic requirements for FSHD remain asymptomatic throughout their lives. Here we investigated family cohorts of FSHD1 individuals who were either affected (manifesting) or without any discernible weakness (nonmanifesting/asymptomatic) and their unaffected family members to determine if individual epigenetic status and stability of repression at the contracted 4q35 D4Z4 array in myocytes correlates with FSHD disease. Results Family cohorts were analyzed for DNA methylation on the distal pathogenic 4q35 D4Z4 repeat on permissive A-type subtelomeres. We found DNA hypomethylation in FSHD1-affected subjects, hypermethylation in healthy controls, and distinctly intermediate levels of methylation in nonmanifesting subjects. We next tested if these differences in DNA methylation had functional relevance by assaying DUX4-fl expression and the stability of epigenetic repression of DUX4-fl in myogenic cells. Treatment with drugs that alter epigenetic status revealed that healthy cells were refractory to treatment, maintaining stable repression of DUX4, while FSHD1-affected cells were highly responsive to treatment and thus epigenetically poised to express DUX4. Myocytes from nonmanifesting subjects had significantly higher levels of DNA methylation and were more resistant to DUX4 activation in response to epigenetic drug treatment than cells from FSHD1-affected first-degree relatives containing the same contraction, indicating that the epigenetic status of the contracted D4Z4 array is reflective of disease. Conclusions The epigenetic status of the distal 4qA D4Z4 repeat correlates with FSHD disease; FSHD-affected subjects have hypomethylation, healthy unaffected subjects have hypermethylation, and nonmanifesting subjects have characteristically intermediate methylation. Thus, analysis of DNA methylation at the distal D4Z4 repeat could be used as a diagnostic indicator of developing clinical FSHD. In addition, the stability of epigenetic repression upstream of DUX4 expression is a key regulator of disease and a viable therapeutic target. Electronic supplementary material The online version of this article (doi:10.1186/s13148-015-0072-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Takako I Jones
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Oliver D King
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA
| | - Charis L Himeda
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA
| | - Sachiko Homma
- Neuromuscular Biology & Disease Group, Departments of Neurology and Physiology & Biophysics, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118 USA
| | - Jennifer C J Chen
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA
| | - Mary Lou Beermann
- Neuromuscular Biology & Disease Group, Departments of Neurology and Physiology & Biophysics, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118 USA
| | - Chi Yan
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; Key Lab of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Wuhan, 430070 People's Republic of China
| | - Charles P Emerson
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA
| | - Jeffrey B Miller
- Neuromuscular Biology & Disease Group, Departments of Neurology and Physiology & Biophysics, Boston University School of Medicine, 72 E Concord St, Boston, MA 02118 USA
| | - Kathryn R Wagner
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA ; The Hugo W. Moser Research Institute, Kennedy Krieger Institute, and the Departments of Neurology and Neuroscience, The Johns Hopkins School of Medicine, 733 N Broadway, Baltimore, MD 21205 USA
| | - Peter L Jones
- Department of Neurology and Department of Cell and Developmental Biology, The Wellstone Program, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, 31 Center Drive, Bethesda, MD USA
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van den Boogaard ML, Lemmers RJFL, Camaño P, van der Vliet PJ, Voermans N, van Engelen BGM, Lopez de Munain A, Tapscott SJ, van der Stoep N, Tawil R, van der Maarel SM. Double SMCHD1 variants in FSHD2: the synergistic effect of two SMCHD1 variants on D4Z4 hypomethylation and disease penetrance in FSHD2. Eur J Hum Genet 2015; 24:78-85. [PMID: 25782668 DOI: 10.1038/ejhg.2015.55] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 02/17/2015] [Accepted: 02/20/2015] [Indexed: 01/03/2023] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) predominantly affects the muscles in the face, trunk and upper extremities and is marked by large clinical variability in disease onset and progression. FSHD is associated with partial chromatin relaxation of the D4Z4 repeat array on chromosome 4 and the somatic expression of the D4Z4 encoded DUX4 gene. The most common form, FSHD1, is caused by a contraction of the D4Z4 repeat array on chromosome 4 to a size of 1-10 units. FSHD2, the less common form of FSHD, is most often caused by heterozygous variants in the chromatin modifier SMCHD1, which is involved in the maintenance of D4Z4 methylation. We identified three families in which the proband carries two potentially damaging SMCHD1 variants. We investigated whether these variants were located in cis or in trans and determined their functional consequences by detailed clinical information and D4Z4 methylation studies. In the first family, both variants in trans were shown to act synergistically on D4Z4 hypomethylation and disease penetrance, in the second family both SMCHD1 function-affecting variants were located in cis while in the third family one of the two variants did not affect function. This study demonstrates that having two SMCHD1 missense variants that affect function is compatible with life in males and females, which is remarkable considering its role in X inactivation in mice. The study also highlights the variability in SMCHD1 variants underlying FSHD2 and the predictive value of D4Z4 methylation analysis in determining the functional consequences of SMCHD1 variants of unknown significance.
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Affiliation(s)
| | - Richard J F L Lemmers
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Pilar Camaño
- Neurosciences, BioDonostia Health Research Institute, Hospital Donostia, San Sebastián, Spain
| | | | - Nicol Voermans
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | | | - Adolfo Lopez de Munain
- Neurosciences, BioDonostia Health Research Institute, Hospital Donostia, San Sebastián, Spain
| | - Stephen J Tapscott
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Nienke van der Stoep
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, MN, USA
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Diagnostic approach for FSHD revisited: SMCHD1 mutations cause FSHD2 and act as modifiers of disease severity in FSHD1. Eur J Hum Genet 2014; 23:808-16. [PMID: 25370034 DOI: 10.1038/ejhg.2014.191] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/13/2014] [Accepted: 08/19/2014] [Indexed: 11/08/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular disorder with a wide clinical variability. Contractions of the D4Z4 macrosatellite repeat on chromosome 4q35 are the molecular basis of the pathophysiology. Recently, in a subset of patients without D4Z4 repeat contractions, variants in the SMCHD1 gene have been identified that lead to hypomethylation of D4Z4 and thus DUX4 transcription, which causes FSHD type 2. In this study, we have screened 55 FSHD1-negative and 40 FSHD1-positive patients from unrelated families for potentially pathogenic variants in SMCHD1 by next-generation sequencing (NGS). We identified variants in SMCHD1 in 11 index patients, including missense, splice site and non-sense mutations. We developed a pyrosequencing assay to determine the methylation status of the D4Z4 repeat array and found significantly lower methylation levels for FSHD2 patients than for healthy controls and FSHD1 patients. Two out of eleven SMCHD1 mutation carriers had moderately contracted D4Z4 alleles thus these patients are suffering from FSHD1 and 2. Comparing the phenotype of patients, all FSHD2 patients were relatively mildly affected while patients with FSHD1+2 were much more severely affected than expected from their D4Z4 copy number. Our findings confirm the role of SMCHD1 mutations in FSHD2 and as a modifier of disease severity. With SMCHD1 variants found in 16.4% of phenotypic FSHD patients without D4Z4 repeat contractions, the incidence of FSHD2 is rather high and hence we suggest including sequencing of SMCHD1, haplotyping and methylation analysis in the workflow of molecular FSHD diagnostics.
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Jones TI, Yan C, Sapp PC, McKenna-Yasek D, Kang PB, Quinn C, Salameh JS, King OD, Jones PL. Identifying diagnostic DNA methylation profiles for facioscapulohumeral muscular dystrophy in blood and saliva using bisulfite sequencing. Clin Epigenetics 2014; 6:23. [PMID: 25400706 PMCID: PMC4232706 DOI: 10.1186/1868-7083-6-23] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/17/2014] [Indexed: 12/20/2022] Open
Abstract
Background Facioscapulohumeral muscular dystrophy (FSHD) is linked to chromatin relaxation due to epigenetic changes at the 4q35 D4Z4 macrosatellite array. Molecular diagnostic criteria for FSHD are complex and involve analysis of high molecular weight (HMW) genomic DNA isolated from lymphocytes, followed by multiple restriction digestions, pulse-field gel electrophoresis (PFGE), and Southern blotting. A subject is genetically diagnosed as FSHD1 if one of the 4q alleles shows a contraction in the D4Z4 array to below 11 repeats, while maintaining at least 1 repeat, and the contraction is in cis with a disease-permissive A-type subtelomere. FSHD2 is contraction-independent and cannot be diagnosed or excluded by this common genetic diagnostic procedure. However, FSHD1 and FSHD2 are linked by epigenetic deregulation, assayed as DNA hypomethylation, of the D4Z4 array on FSHD-permissive alleles. We have developed a PCR-based assay that identifies the epigenetic signature for both types of FSHD, distinguishing FSHD1 from FSHD2, and can be performed on genomic DNA isolated from blood, saliva, or cultured cells. Results Samples were obtained from healthy controls or patients clinically diagnosed with FSHD, and include both FSHD1 and FSHD2. The genomic DNAs were subjected to bisulfite sequencing analysis for the distal 4q D4Z4 repeat with an A-type subtelomere and the DUX4 5’ promoter region. We compared genomic DNA isolated from saliva and blood from the same individuals and found similar epigenetic signatures. DNA hypomethylation was restricted to the contracted 4qA chromosome in FSHD1 patients while healthy control subjects were hypermethylated. Candidates for FSHD2 showed extreme DNA hypomethylation on the 4qA DUX4 gene body as well as all analyzed DUX4 5’ sequences. Importantly, our assay does not amplify the D4Z4 arrays with non-permissive B-type subtelomeres and accurately excludes the arrays with non-permissive A-type subtelomeres. Conclusions We have developed an assay to identify changes in DNA methylation on the pathogenic distal 4q D4Z4 repeat. We show that the DNA methylation profile of saliva reflects FSHD status. This assay can distinguish FSHD from healthy controls, differentiate FSHD1 from FSHD2, does not require HMW genomic DNA or PFGE, and can be performed on either cultured cells, tissue, blood, or saliva samples. Electronic supplementary material The online version of this article (doi:10.1186/1868-7083-6-23) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Takako I Jones
- The Wellstone Program & The Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Chi Yan
- The Wellstone Program & The Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; Key Lab of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070 P.R. China
| | - Peter C Sapp
- The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Diane McKenna-Yasek
- The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Peter B Kang
- Department of Pediatrics, Division of Pediatric Neurology, University of Florida College of Medicine, 1600 SW Archer Road, Gainesville, FL 32607 USA
| | - Colin Quinn
- The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; Department of Neurology, Hospital of the University of Pennsylvania, 3400 Spruce St, 3 Gates, Philadelphia, PA 19104 USA
| | - Johnny S Salameh
- The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Oliver D King
- The Wellstone Program & The Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Peter L Jones
- The Wellstone Program & The Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA ; The Eunice Kennedy Shriver National Institute of Child Health and Human Development Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
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Himeda CL, Debarnot C, Homma S, Beermann ML, Miller JB, Jones PL, Jones TI. Myogenic enhancers regulate expression of the facioscapulohumeral muscular dystrophy-associated DUX4 gene. Mol Cell Biol 2014; 34:1942-55. [PMID: 24636994 PMCID: PMC4019064 DOI: 10.1128/mcb.00149-14] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 02/12/2014] [Accepted: 03/11/2014] [Indexed: 11/20/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is linked to epigenetic dysregulation of the chromosome 4q35 D4Z4 macrosatellite. However, this does not account for the tissue specificity of FSHD pathology, which requires stable expression of an alternative full-length mRNA splice form of DUX4 (DUX4-fl) from the D4Z4 array in skeletal muscle. Here, we describe the identification of two enhancers, DUX4 myogenic enhancer 1 (DME1) and DME2 which activate DUX4-fl expression in skeletal myocytes but not fibroblasts. Analysis of the chromatin revealed histone modifications and RNA polymerase II occupancy consistent with DME1 and DME2 being functional enhancers. Chromosome conformation capture analysis confirmed association of DME1 and DME2 with the DUX4 promoter in vivo. The strong interaction between DME2 and the DUX4 promoter in both FSHD and unaffected primary myocytes was greatly reduced in fibroblasts, suggesting a muscle-specific interaction. Nucleosome occupancy and methylome sequencing analysis indicated that in most FSHD myocytes, both enhancers are associated with nucleosomes but have hypomethylated DNA, consistent with a permissive transcriptional state, sporadic occupancy, and the observed DUX4 expression in rare myonuclei. Our data support a model in which these myogenic enhancers associate with the DUX4 promoter in skeletal myocytes and activate transcription when epigenetically derepressed in FSHD, resulting in the pathological misexpression of DUX4-fl.
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Affiliation(s)
- Charis L. Himeda
- Wellstone Program, Departments of Cell and Developmental Biology and Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Céline Debarnot
- Ecole Supérieure de Biotechnologie Strasbourg, Illkirch, France
| | - Sachiko Homma
- Neuromuscular Biology and Disease Group, Departments of Neurology and Physiology Biophysics, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Mary Lou Beermann
- Neuromuscular Biology and Disease Group, Departments of Neurology and Physiology Biophysics, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Jeffrey B. Miller
- Neuromuscular Biology and Disease Group, Departments of Neurology and Physiology Biophysics, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Peter L. Jones
- Wellstone Program, Departments of Cell and Developmental Biology and Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Takako I. Jones
- Wellstone Program, Departments of Cell and Developmental Biology and Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Massah S, Hollebakken R, Labrecque MP, Kolybaba AM, Beischlag TV, Prefontaine GG. Epigenetic characterization of the growth hormone gene identifies SmcHD1 as a regulator of autosomal gene clusters. PLoS One 2014; 9:e97535. [PMID: 24818964 PMCID: PMC4018343 DOI: 10.1371/journal.pone.0097535] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 04/21/2014] [Indexed: 12/31/2022] Open
Abstract
Regulatory elements for the mouse growth hormone (GH) gene are located distally in a putative locus control region (LCR) in addition to key elements in the promoter proximal region. The role of promoter DNA methylation for GH gene regulation is not well understood. Pit-1 is a POU transcription factor required for normal pituitary development and obligatory for GH gene expression. In mammals, Pit-1 mutations eliminate GH production resulting in a dwarf phenotype. In this study, dwarf mice illustrated that Pit-1 function was obligatory for GH promoter hypomethylation. By monitoring promoter methylation levels during developmental GH expression we found that the GH promoter became hypomethylated coincident with gene expression. We identified a promoter differentially methylated region (DMR) that was used to characterize a methylation-dependent DNA binding activity. Upon DNA affinity purification using the DMR and nuclear extracts, we identified structural maintenance of chromosomes hinge domain containing -1 (SmcHD1). To better understand the role of SmcHD1 in genome-wide gene expression, we performed microarray analysis and compared changes in gene expression upon reduced levels of SmcHD1 in human cells. Knock-down of SmcHD1 in human embryonic kidney (HEK293) cells revealed a disproportionate number of up-regulated genes were located on the X-chromosome, but also suggested regulation of genes on non-sex chromosomes. Among those, we identified several genes located in the protocadherin β cluster. In addition, we found that imprinted genes in the H19/Igf2 cluster associated with Beckwith-Wiedemann and Silver-Russell syndromes (BWS & SRS) were dysregulated. For the first time using human cells, we showed that SmcHD1 is an important regulator of imprinted and clustered genes.
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Affiliation(s)
- Shabnam Massah
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Robert Hollebakken
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Mark P. Labrecque
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Addie M. Kolybaba
- Faculty of Biology, Ludwig Maximilians University Munich, Martinsried, Germany
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