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Pegat A, Streichenberger N, Lacoste N, Hermier M, Menassa R, Coudert L, Theuriet J, Froissart R, Terrone S, Bouhour F, Michel-Calemard L, Schaeffer L, Jacquier A. Novel Intronic Mutation in VMA21 Causing Severe Phenotype of X-Linked Myopathy with Excessive Autophagy-Case Report. Genes (Basel) 2022; 13:genes13122245. [PMID: 36553512 PMCID: PMC9777698 DOI: 10.3390/genes13122245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/18/2022] [Accepted: 11/26/2022] [Indexed: 12/02/2022] Open
Abstract
X-linked Myopathy with Excessive Autophagy (XMEA) is a rare autophagic vacuolar myopathy caused by mutations in the Vacuolar ATPase assembly factor VMA21 gene; onset usually occurs during childhood and rarely occurs during adulthood. We described a 22-year-old patient with XMEA, whose onset was declared at 11 through gait disorder. He had severe four-limb proximal weakness and amyotrophy, and his proximal muscle MRC score was between 2 and 3/5 in four limbs; creatine kinase levels were elevated (1385 IU/L), and electroneuromyography and muscle MRI were suggestive of myopathy. Muscle biopsy showed abnormalities typical of autophagic vacuolar myopathy. We detected a hemizygous, unreported, intronic, single-nucleotide substitution c.164-20T>A (NM_001017980.4) in intron 2 of the VMA21 gene. Fibroblasts derived from this patient displayed a reduced level of VMA21 transcripts (at 40% of normal) and protein, suggesting a pathogenicity related to an alteration of the splicing efficiency associated with an intron retention. This patient with XMEA displayed a severe phenotype (rapid weakness of upper and lower limbs) due to a new intronic variant of VMA21, related to an alteration in the splicing efficiency associated with intron retention, suggesting that phenotype severity is closely related to the residual expression of the VMA21 protein.
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Affiliation(s)
- Antoine Pegat
- Service ENMG et Pathologies Neuromusculaires, Hôpital Neurologique P. Wertheimer, Hospices Civils de Lyon, 69500 Bron, France
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Correspondence: (A.P.); (A.J.)
| | - Nathalie Streichenberger
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Service d’anatomopathologie, Centre de Biologie et Pathologie Est (CBPE), Hospices Civils de Lyon, 69500 Bron, France
| | - Nicolas Lacoste
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
| | - Marc Hermier
- Service de Neuroradiologie, Hôpital Neurologique P. Wertheimer, Hospices Civils de Lyon, 69500 Bron, France
| | - Rita Menassa
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Service de Biochimie et Biologie Moléculaire, Centre de Biologie et Pathologie Est (CBPE), Hospices Civils de Lyon, 69500 Bron, France
| | - Laurent Coudert
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
| | - Julian Theuriet
- Service ENMG et Pathologies Neuromusculaires, Hôpital Neurologique P. Wertheimer, Hospices Civils de Lyon, 69500 Bron, France
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
| | - Roseline Froissart
- Service de Biochimie et Biologie Moléculaire, Centre de Biologie et Pathologie Est (CBPE), Hospices Civils de Lyon, 69500 Bron, France
| | - Sophie Terrone
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
| | - Francoise Bouhour
- Service ENMG et Pathologies Neuromusculaires, Hôpital Neurologique P. Wertheimer, Hospices Civils de Lyon, 69500 Bron, France
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
| | - Laurence Michel-Calemard
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Service de Biochimie et Biologie Moléculaire, Centre de Biologie et Pathologie Est (CBPE), Hospices Civils de Lyon, 69500 Bron, France
| | - Laurent Schaeffer
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Centre de Biotechnologie Cellulaire, CBC Biotec, Hospices Civils de Lyon-Groupement Est, 69500 Bron, France
| | - Arnaud Jacquier
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, INMG, Université Claude Bernard Lyon 1, Faculté de Médecine Lyon Est, 69008 Lyon, France
- Centre de Biotechnologie Cellulaire, CBC Biotec, Hospices Civils de Lyon-Groupement Est, 69500 Bron, France
- Correspondence: (A.P.); (A.J.)
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Rajeshwari M, Dhiman N, Chakrabarty B, Gulati S, Shamim U, Faruq M, Suri V, Sharma MC. X-linked Myopathy with Excessive Autophagy - A Rare Cause of Vacuolar Myopathy in Children. Neurol India 2022; 70:1643-1648. [PMID: 36076674 DOI: 10.4103/0028-3886.355110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
X-linked myopathy with excessive autophagy (XMEA) is a rare, recently characterized type of autophagic vacuolar myopathy caused by mutations in the VMA21 gene. It is characterized by slowly progressive weakness restricted to proximal limb muscles and generally has a favorable outcome. The characteristic histological and ultrastructural features distinguish this entity from other mimics, notably Danon disease. XMEA is an under recognized disease and should be considered in the differentials of slowly progressive myopathy in children. Awareness of this rare entity is also important for the pathologists in order to distinguish it from other causes of vacuolar myopathy in view of its favourable prognosis. We report the first genetically confirmed case of XMEA from India in an 8-year-old boy which was diagnosed based on the characteristic light microscopic and ultrastructural findings on muscle biopsy and subsequently confirmed by mutation analysis. The differential diagnostic considerations are also discussed.
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Affiliation(s)
- Madhu Rajeshwari
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Neena Dhiman
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Biswaroop Chakrabarty
- Department of Pediatrics (Child Neurology Division), All India Institute of Medical Sciences, New Delhi, India
| | - Sheffali Gulati
- Department of Pediatrics (Child Neurology Division), All India Institute of Medical Sciences, New Delhi, India
| | - Uzma Shamim
- Department of Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Mohammed Faruq
- Department of Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Vaishali Suri
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Mehar Chand Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
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Dowling JJ, Moore SA, Kalimo H, Minassian BA. X-linked myopathy with excessive autophagy: a failure of self-eating. Acta Neuropathol 2015; 129:383-90. [PMID: 25644398 DOI: 10.1007/s00401-015-1393-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 12/15/2022]
Abstract
Autophagic vacuolar myopathies (AVMs) are a group of disorders united by shared histopathological features on muscle biopsy that include the aberrant accumulation of autophagic vacuoles. The classic conditions that compose the AVMs include Pompe Disease, Danon Disease and X-linked myopathy with excessive autophagy (XMEA). Other disorders, including acquired myopathies like chloroquine toxicity, also have features of an autophagic myopathy. This review is focused on XMEA, a myopathy with onset of slowly progressive proximal weakness and elevated serum creatine kinase (2× to 20× normal) typically in the first decade of life. However, both late-adult onset and severe, sometimes lethal, neonatal cases also occur. Skeletal muscle pathology is characterized by numerous cytoplasmic autophagic vacuoles, complex muscle fiber splitting with internalization of capillaries, and complement C5b-9 deposition within vacuoles and along the sarcolemma. The autophagic vacuoles have sarcolemmal features. Mutations in the VMA21 gene at Xq28 cause XMEA by reducing the activity of lysosomal hydrolases. The VMA21 protein regulates the assembly of the V-ATPase required to acidify the lysosome. Increased lysosomal pH and poor degradation of cellular debris may secondarily induce autophagy, the net effect being accumulation of autophagolysosomes. The relationship of XMEA to other lysosomal disorders of muscle and potential therapeutic interventions for XMEA are discussed.
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Affiliation(s)
- James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada,
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Abstract
Electrodiagnostic testing is a useful component of the approach to a patient with suspected myopathy. It follows the history and is guided by the neurologic examination findings. Uncovering various electrodiagnostic patterns (eg, fibrillation potentials with short-duration motor unit potentials, short-duration motor unit potentials without fibrillation potentials, myotonic discharges, and short-duration motor unit potentials with complex repetitive discharges) can lead to more targeted laboratory testing and a refined differential diagnosis. Electromyography may also be used to detect subclinical myopathy, assess disease activity, and help select a suitable muscle for biopsy.
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Affiliation(s)
- David Lacomis
- Division of Neuromuscular Diseases, University of Pittsburgh School of Medicine, UPMC- Presbyterian, F875, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
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