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Lilleker JB, Naddaf E, Saris CGJ, Schmidt J, de Visser M, Weihl CC. 272nd ENMC international workshop: 10 Years of progress - revision of the ENMC 2013 diagnostic criteria for inclusion body myositis and clinical trial readiness. 16-18 June 2023, Hoofddorp, The Netherlands. Neuromuscul Disord 2024; 37:36-51. [PMID: 38522330 DOI: 10.1016/j.nmd.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/26/2024]
Abstract
Since the publication of the 2013 European Neuromuscular Center (ENMC) diagnostic criteria for Inclusion Body Myositis (IBM), several advances have been made regarding IBM epidemiology, pathogenesis, diagnostic tools, and clinical trial readiness. Novel diagnostic tools include muscle imaging techniques such as MRI and ultrasound, and serological testing for cytosolic 5'-nucleotidase-1A antibodies. The 272nd ENMC workshop aimed to develop new diagnostic criteria, discuss clinical outcome measures and clinical trial readiness. The workshop started with patient representatives highlighting several understudied symptoms and the urge for a timely diagnosis. This was followed by presentations from IBM experts highlighting the new developments in the field. This report is composed of two parts, the first part providing new diagnostic criteria on which consensus was achieved. The second part focuses on the use of outcome measures in clinical practice and clinical trials, highlighting current limitations and outlining the goals for future studies.
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Affiliation(s)
- James B Lilleker
- Manchester Centre for Clinical Neurosciences, Northern Care Alliance NHS Foundation Trust, Manchester Academic Health Science Centre, Salford, UK; Division of Musculoskeletal and Dermatological Sciences, The University of Manchester, Manchester, UK
| | - Elie Naddaf
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Christiaan G J Saris
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jens Schmidt
- Department of Neurology and Pain Treatment, Neuromuscular Center and Center for Translational Medicine, Immanuel Klinik Rüdersdorf, University Hospital of the Brandenburg Medical School MHB, Rüdersdorf bei Berlin, Germany; Faculty of Health Sciences Brandenburg, Brandenburg Medical School Theodor Fontane, Rüdersdorf bei Berlin, Germany; Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Marianne de Visser
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Conrad C Weihl
- Neuromuscular Division, Washington University School of Medicine, Saint Louis, MO, USA.
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Donkervoort S, Mohassel P, O'Leary M, Bonner DE, Hartley T, Acquaye N, Brull A, Mozaffar T, Saporta MA, Dyment DA, Sampson JB, Pajusalu S, Austin-Tse C, Hurth K, Cohen JS, McWalter K, Warman-Chardon J, Crunk A, Foley AR, Mammen AL, Wheeler MT, O'Donnell-Luria A, Bönnemann CG. Recurring homozygous ACTN2 variant (p.Arg506Gly) causes a recessive myopathy. Ann Clin Transl Neurol 2024; 11:629-640. [PMID: 38311799 DOI: 10.1002/acn3.51983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/10/2023] [Accepted: 12/16/2023] [Indexed: 02/06/2024] Open
Abstract
OBJECTIVE ACTN2, encoding alpha-actinin-2, is essential for cardiac and skeletal muscle sarcomeric function. ACTN2 variants are a known cause of cardiomyopathy without skeletal muscle involvement. Recently, specific dominant monoallelic variants were reported as a rare cause of core myopathy of variable clinical onset, although the pathomechanism remains to be elucidated. The possibility of a recessively inherited ACTN2-myopathy has also been proposed in a single series. METHODS We provide clinical, imaging, and histological characterization of a series of patients with a novel biallelic ACTN2 variant. RESULTS We report seven patients from five families with a recurring biallelic variant in ACTN2: c.1516A>G (p.Arg506Gly), all manifesting with a consistent phenotype of asymmetric, progressive, proximal, and distal lower extremity predominant muscle weakness. None of the patients have cardiomyopathy or respiratory insufficiency. Notably, all patients report Palestinian ethnicity, suggesting a possible founder ACTN2 variant, which was confirmed through haplotype analysis in two families. Muscle biopsies reveal an underlying myopathic process with disruption of the intermyofibrillar architecture, Type I fiber predominance and atrophy. MRI of the lower extremities demonstrate a distinct pattern of asymmetric muscle involvement with selective involvement of the hamstrings and adductors in the thigh, and anterior tibial group and soleus in the lower leg. Using an in vitro splicing assay, we show that c.1516A>G ACTN2 does not impair normal splicing. INTERPRETATION This series further establishes ACTN2 as a muscle disease gene, now also including variants with a recessive inheritance mode, and expands the clinical spectrum of actinopathies to adult-onset progressive muscle disease.
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Affiliation(s)
- Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Melanie O'Leary
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Devon E Bonner
- Stanford Center for Undiagnosed Diseases, Stanford University, Stanford, California, USA
- Department of Pediatrics, Medical Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Taila Hartley
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicole Acquaye
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Astrid Brull
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Tahseen Mozaffar
- Department of Neurology, University of California, Irvine, California, USA
- Department of Pathology & Laboratory Medicine, University of California, Irvine, California, USA
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Jacinda B Sampson
- Stanford Center for Undiagnosed Diseases, Stanford University, Stanford, California, USA
- Department of Neurology, Stanford University School of Medicine, Stanford, California, USA
| | - Sander Pajusalu
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Genetics and Personalized Medicine Clinic, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Christina Austin-Tse
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kyle Hurth
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Julie S Cohen
- Department of Neurology and Developmental Medicine, Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Jodi Warman-Chardon
- Department of Medicine, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada
| | | | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew L Mammen
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Muscle Disease Unit, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Matthew T Wheeler
- Stanford Center for Undiagnosed Diseases, Stanford University, Stanford, California, USA
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Anne O'Donnell-Luria
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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Mulvany-Robbins B, Putko B, Schmitt L, Oudit G, Phan C, Beecher G. Novel p.Asp27Glu ACTA1 variant features congenital myopathy with finger flexor weakness, cardiomyopathy, and cardiac conduction defects. Neuromuscul Disord 2023; 33:546-550. [PMID: 37315422 DOI: 10.1016/j.nmd.2023.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/25/2023] [Accepted: 05/29/2023] [Indexed: 06/16/2023]
Abstract
Pathogenic variants in the skeletal muscle α-actin 1 gene (ACTA1) cause a spectrum of myopathies with clinical and myopathological diversity. Clinical presentations occur from the prenatal period to adulthood, commonly with proximal-predominant weakness and rarely preferential distal weakness. Myopathological findings are wide-ranging, with nemaline rods being most frequent. Associated cardiomyopathy is rare and conduction defects are not reported. We describe a family with congenital myopathy with prominent finger flexor weakness and cardiomyopathy with cardiac conduction defects. The proband, a 48-year-old Caucasian male, his 73-year-old mother, 41-year-old sister, and 19-year-old nephew presented with prominent finger flexor weakness on a background of neonatal hypotonia and delayed motor milestones. All had progressive cardiomyopathy with systolic dysfunction and/or left ventricular dilation. The proband and sister had intraventricular conduction delay and left anterior fascicular block, respectively. The mother had atrial fibrillation. Muscle biopsy in the proband and sister demonstrated congenital fiber-type disproportion and rare nemaline rods in the proband. A novel dominant variant in ACTA1 (c.81C>A, p.Asp27Glu) segregated within the family. This family expands the genotypic and phenotypic spectrum of ACTA1-related myopathy, highlighting preferential finger flexor involvement with cardiomyopathy and conduction disease. We emphasize early and ongoing cardiac surveillance in ACTA1-related myopathy.
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Affiliation(s)
- Bridget Mulvany-Robbins
- Division of Neurology, Department of Medicine, University of Alberta, 7-125 Clinical Sciences Building 11350 83rd Avenue NW, Edmonton, AB, Canada T6G 2G3
| | - Brendan Putko
- Division of Neurology, Department of Medicine, University of Alberta, 7-125 Clinical Sciences Building 11350 83rd Avenue NW, Edmonton, AB, Canada T6G 2G3
| | - Laura Schmitt
- Section of Neuropathology, Department of Laboratory Medicine and Pathology, University of Alberta, 8440 112St NW, Edmonton, AB, Canada T6G 2B7
| | - Gavin Oudit
- Division of Cardiology, Department of Medicine, Mazankowski Alberta Health Institute, 11220 83 Ave NW, Edmonton, AB T6G 2B7
| | - Cecile Phan
- Division of Neurology, Department of Medicine, University of Alberta, 7-125 Clinical Sciences Building 11350 83rd Avenue NW, Edmonton, AB, Canada T6G 2G3
| | - Grayson Beecher
- Division of Neurology, Department of Medicine, University of Alberta, 7-125 Clinical Sciences Building 11350 83rd Avenue NW, Edmonton, AB, Canada T6G 2G3.
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Paul P, Liewluck T, Ernste FC, Mandrekar J, Milone M. Anti-cN1A antibodies do not correlate with specific clinical, electromyographic, or pathological findings in sporadic inclusion body myositis. Muscle Nerve 2021; 63:490-496. [PMID: 33373040 DOI: 10.1002/mus.27157] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/17/2020] [Accepted: 12/23/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND Anti-cytosolic 5'-nucleotidase 1A (cN1A) antibodies are commonly detected in patients with sporadic inclusion body myositis (sIBM). However, their pathogenic role has not been established. Moreover, efforts toward identifying sIBM distinct clinicopathologic characteristics associated with these antibodies have yielded conflicting results. METHODS We first searched for patients, seen in our clinics, tested for anti-cN1A antibodies between December 2015 and December 2019. We identified 92 patients who were diagnosed with sIBM, according to the 2011 ENMC or Griggs et al criteria. Thereafter, we reviewed and compared the clinical and investigational findings of these patients in relation to their antibody status. RESULTS Anti-cN1A antibodies were present in 47/92 (51%) patients with sIBM. Comparison of seropositive and seronegative cohorts yielded no significant difference in clinical features, including facial weakness, oropharyngeal and respiratory involvement, or disease severity. The antibody titer did not correlate with the clinical phenotype, CK value, or presence of myotonic discharges on EMG. Anti-cN1A antibody positive patients appeared to have more frequent auto-aggressive inflammation on muscle biopsy but not as an isolated myopathological feature. CONCLUSIONS Our study showed that anti-cN1A antibody positive and negative sIBM patients have similar clinical features and disease severity. Anti-cN1A antibodies in our sIBM cohort did not correlate with any studied clinical or laboratory parameter and, therefore, were of limited value in the patient's assessment.
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Affiliation(s)
- Pritikanta Paul
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Jay Mandrekar
- Biomedical Statistics and Bioinformatics, Mayo Clinic, Rochester, Minnesota, USA
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