[en] [en] AIMS: Limb-girdle congenital myasthenic syndrome (LG-CMS) is a genetically heterogeneous disorder characterized by muscle weakness and fatigability. The LG-CMS gene DPAGT1 codes for an essential enzyme of the glycosylation pathway, a posttranslational modification mechanism shaping the structure and function of proteins. In DPAGT1-related LG-CMS, reduced glycosylation of the acetylcholine receptor (AChR) reduces its localization at the neuromuscular junction (NMJ), and results in diminished neuromuscular transmission. LG-CMS patients also show tubular aggregates on muscle biopsy, but the origin and potential contribution of the aggregates to disease development are not understood. Here, we describe two LG-CMS patients with the aim of providing a molecular diagnosis and to shed light on the pathways implicated in tubular aggregate formation.
METHODS: Following clinical examination of the patients, we performed next-generation sequencing (NGS) to identify the genetic causes, analysed the biopsies at the histological and ultrastructural levels, investigated the composition of the tubular aggregates, and performed experiments on protein glycosylation.
RESULTS: We identified novel pathogenic DPAGT1 variants in both patients, and pyridostigmine treatment quantitatively improved muscle force and function. The tubular aggregates contained proteins of the sarcoplasmic reticulum (SR) and structurally conformed to the aggregates observed in tubular aggregate myopathy (TAM). TAM arises from overactivation of the plasma membrane calcium channel ORAI1, and functional studies on muscle extracts from our LG-CMS patients evidenced abnormal ORAI1 glycosylation.
CONCLUSIONS: We expand the genetic variant spectrum of LG-CMS and provide a genotype/phenotype correlation for pathogenic DPAGT1 variants. The discovery of ORAI1 hypoglycosylation in our patients highlights a physiopathological link between LG-CMS and TAM.
Disciplines :
Neurology
Author, co-author :
Vanden Brande, Laura ; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France ; Assistance Publique Hôpitaux de Paris, Sorbonne Université, Institut de Myologie, AFM-Téléthon, Essais cliniques I-Motion Enfants, Hôpital Armand Trousseau, Paris, France
Bauché, Stéphanie; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France ; Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
Pérez-Guàrdia, Laura; Departement of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Inserm U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
Sternberg, Damien; Service de Biochimie Métabolique, UF Cardiogenetics and Myogenetics, Hôpital de la Pitié-Salpêtrière, APHP, Paris, France
Seferian, Andreea M; Assistance Publique Hôpitaux de Paris, Sorbonne Université, Institut de Myologie, AFM-Téléthon, Essais cliniques I-Motion Enfants, Hôpital Armand Trousseau, Paris, France
Malfatti, Edoardo; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France ; Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
Silva-Rojas, Roberto; Departement of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Inserm U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
Labasse, Clémence; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France
Chevessier, Frédéric; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France
Carlier, Pierre; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France
Eymard, Bruno; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France ; Centre de Référence de Pathologie Neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
Romero, Norma B; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France
Laporte, Jocelyn; Departement of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Inserm U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
Servais, Laurent ; Université de Liège - ULiège > Département des sciences cliniques ; MDUK Oxford Neuromuscular Centre & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
Gidaro, Teresa; Institut de Myologie, GHU La Pitié-Salpêtrière, Paris, France ; Assistance Publique Hôpitaux de Paris, Sorbonne Université, Institut de Myologie, AFM-Téléthon, Essais cliniques I-Motion Enfants, Hôpital Armand Trousseau, Paris, France
Böhm, Johann ; Departement of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Inserm U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
French Muscular Dystrophy Association Fondation Maladies Rares FRM - Fondation pour la Recherche Médicale
Funding text :
We thank the patients and their families for their interest and participation in the study; Jean-François Deleuze, Anne Boland and Bertrand Fin (CNRGH) for their technical NGS expertise; and Sophie Nicole (ICM) for her technical help.This work was supported by the Association Institute of Myology (AIM), Inserm, CNRS, University of Strasbourg, Labex INRT (ANR‐10‐LABX‐0030 and ANR‐10‐IDEX‐0002‐02), Association Française contre les Myopathies (AFM‐22734), and France Génomique (ANR‐10‐INBS‐09) and Fondation Maladies Rares within the frame of the ‘Myocapture’ sequencing project. RSR was funded by a Fondation pour la Recherche Médicale doctoral fellowship (FRM, PLP20170939073). Funding information
Engel AG, Shen XM, Selcen D, Sine SM. Congenital myasthenic syndromes: pathogenesis, diagnosis, and treatment. Lancet Neurol. 2015;14(4):420-434. doi:10.1016/S1474-4422(14)70201-7
Nicole S, Azuma Y, Bauche S, Eymard B, Lochmuller H, Slater C. Congenital myasthenic syndromes or inherited disorders of neuromuscular transmission: recent discoveries and open questions. J Neuromuscul Dis. 2017;4(4):269-284. doi:10.3233/JND-170257
Evangelista T, Hanna M, Lochmuller H. Congenital myasthenic syndromes with predominant limb girdle weakness. J Neuromuscular Dis. 2015;2(Suppl 2):S21-S29. doi:10.3233/JND-150098
O'Connor E, Topf A, Zahedi RP, et al. Clinical and research strategies for limb-girdle congenital myasthenic syndromes. Ann N Y Acad Sci. 2018;1412(1):102-112. doi:10.1111/nyas.13520
Cossins J, Belaya K, Hicks D, et al. Congenital myasthenic syndromes due to mutations in ALG2 and ALG14. Brain. 2013;136(Pt 3):944-956. doi:10.1093/brain/awt010
Belaya K, Finlayson S, Slater CR, et al. Mutations in DPAGT1 cause a limb-girdle congenital myasthenic syndrome with tubular aggregates. Am J Hum Genet. 2012;91(1):193-201. doi:10.1016/j.ajhg.2012.05.022
Guergueltcheva V, Muller JS, Dusl M, et al. Congenital myasthenic syndrome with tubular aggregates caused by GFPT1 mutations. J Neurol. 2012;259(5):838-850. doi:10.1007/s00415-011-6262-z
Belaya K, Rodriguez Cruz PM, Liu WW, et al. Mutations in GMPPB cause congenital myasthenic syndrome and bridge myasthenic disorders with dystroglycanopathies. Brain. 2015;138(Pt 9):2493-2504. doi:10.1093/brain/awv185
Beeson D, Higuchi O, Palace J, et al. Dok-7 mutations underlie a neuromuscular junction synaptopathy. Science. 2006;313(5795):1975-1978. doi:10.1126/science.1130837
Huze C, Bauche S, Richard P, et al. Identification of an agrin mutation that causes congenital myasthenia and affects synapse function. Am J Hum Genet. 2009;85(2):155-167. doi:10.1016/j.ajhg.2009.06.015
Ohkawara B, Cabrera-Serrano M, Nakata T, et al. LRP4 third beta-propeller domain mutations cause novel congenital myasthenia by compromising agrin-mediated MuSK signaling in a position-specific manner. Hum Mol Genet. 2014;23(7):1856-1868. doi:10.1093/hmg/ddt578
Chevessier F, Faraut B, Ravel-Chapuis A, et al. MUSK, a new target for mutations causing congenital myasthenic syndrome. Hum Mol Genet. 2004;13(24):3229-3240. doi:10.1093/hmg/ddh333
Ohno K, Brengman J, Tsujino A, Engel AG. Human endplate acetylcholinesterase deficiency caused by mutations in the collagen-like tail subunit (ColQ) of the asymmetric enzyme. Proc Natl Acad Sci U S A. 1998;95(16):9654-9659. doi:10.1073/pnas.95.16.9654
Senderek J, Muller JS, Dusl M, et al. Hexosamine biosynthetic pathway mutations cause neuromuscular transmission defect. Am J Hum Genet. 2011;88(2):162-172. doi:10.1016/j.ajhg.2011.01.008
Gehle VM, Walcott EC, Nishizaki T, Sumikawa K. N-glycosylation at the conserved sites ensures the expression of properly folded functional ACh receptors. Brain Res Mol Brain Res. 1997;45(2):219-229. doi:10.1016/S0169-328X(96)00256-2
Zoltowska K, Webster R, Finlayson S, et al. Mutations in GFPT1 that underlie limb-girdle congenital myasthenic syndrome result in reduced cell-surface expression of muscle AChR. Hum Mol Genet. 2013;22(14):2905-2913. doi:10.1093/hmg/ddt145
Mignen O, Thompson JL, Shuttleworth TJ. STIM1 regulates Ca2+ entry via arachidonate-regulated Ca2+-selective (ARC) channels without store depletion or translocation to the plasma membrane. J Physiol. 2007;579(Pt 3):703-715. doi:10.1113/jphysiol.2006.122432
Bogdanova-Mihaylova P, Murphy RPJ, Alexander MD, et al. Congenital myasthenic syndrome due to DPAGT1 mutations mimicking congenital myopathy in an Irish family. Eur J Neurol. 2018;25(2):e22-e23. doi:10.1111/ene.13532
Klein A, Robb S, Rushing E, Liu WW, Belaya K, Beeson D. Congenital myasthenic syndrome caused by mutations in DPAGT. Neuromuscul Disord. 2015;25(3):253-256. doi:10.1016/j.nmd.2014.11.013
Basiri K, Belaya K, Liu WW, Maxwell S, Sedghi M, Beeson D. Clinical features in a large Iranian family with a limb-girdle congenital myasthenic syndrome due to a mutation in DPAGT1. Neuromuscul Disord. 2013;23(6):469-472. doi:10.1016/j.nmd.2013.03.003
Selcen D, Shen XM, Brengman J, et al. DPAGT1 myasthenia and myopathy: genetic, phenotypic, and expression studies. Neurology. 2014;82(20):1822-1830. doi:10.1212/WNL.0000000000000435
Finlayson S, Palace J, Belaya K, et al. Clinical features of congenital myasthenic syndrome due to mutations in DPAGT1. J Neurol Neurosurg Psychiatry. 2013;84(10):1119-1125. doi:10.1136/jnnp-2012-304716
Barone V, del Re V, Gamberucci A, et al. Identification and characterization of three novel mutations in the CASQ1 gene in four patients with tubular aggregate myopathy. Hum Mutat. 2017;38(12):1761-1773. doi:10.1002/humu.23338
Bohm J, Lornage X, Chevessier F, et al. CASQ1 mutations impair calsequestrin polymerization and cause tubular aggregate myopathy. Acta Neuropathol. 2018;135(1):149-151. doi:10.1007/s00401-017-1775-x
Bohm J, Chevessier F, Maues De Paula A, et al. Constitutive activation of the calcium sensor STIM1 causes tubular-aggregate myopathy. Am J Hum Genet. 2013;92(2):271-278. doi:10.1016/j.ajhg.2012.12.007
Nesin V, Wiley G, Kousi M, et al. Activating mutations in STIM1 and ORAI1 cause overlapping syndromes of tubular myopathy and congenital miosis. Proc Natl Acad Sci U S A. 2014;111(11):4197-4202. doi:10.1073/pnas.1312520111
Chevessier F, Bauche-Godard S, Leroy JP, et al. The origin of tubular aggregates in human myopathies. J Pathol. 2005;207(3):313-323. doi:10.1002/path.1832
Morin G, Biancalana V, Echaniz-Laguna A, et al. Tubular aggregate myopathy and Stormorken syndrome: mutation spectrum and genotype/phenotype correlation. Hum Mutat. 2020;41(1):17-37. doi:10.1002/humu.23899
Servais L, Deconinck N, Moraux A, et al. Innovative methods to assess upper limb strength and function in non-ambulant Duchenne patients. Neuromuscul Disord. 2013;23(2):139-148. doi:10.1016/j.nmd.2012.10.022
Hogrel JY, Decostre V, Ledoux I, et al. Normalized grip strength is a sensitive outcome measure through all stages of Duchenne muscular dystrophy. J Neurol. 2020;267(7):2022-2028. doi:10.1007/s00415-020-09800-9
Thomas KC, Zheng XF, Garces Suarez F, et al. Evidence based selection of commonly used RT-qPCR reference genes for the analysis of mouse skeletal muscle. PLoS ONE. 2014;9(2):e88653. doi:10.1371/journal.pone.0088653
McDonald CM, Henricson EK, Han JJ, et al. The 6-minute walk test as a new outcome measure in Duchenne muscular dystrophy. Muscle Nerve. 2010;41(4):500-510. doi:10.1002/mus.21544
Goebel HH. When tubules aggregate. Neuromuscul Disord. 2012;22(3):208-210. doi:10.1016/j.nmd.2011.12.006
Bohm J, Bulla M, Urquhart JE, et al. ORAI1 mutations with distinct channel gating defects in tubular aggregate myopathy. Hum Mutat. 2017;38(4):426-438. doi:10.1002/humu.23172
Reily C, Stewart TJ, Renfrow MB, Novak J. Glycosylation in health and disease. Nat Rev Nephrol. 2019;15(6):346-366. doi:10.1038/s41581-019-0129-4
Ng BG, Underhill HR, Palm L, et al. DPAGT1 deficiency with encephalopathy (DPAGT1-CDG): clinical and genetic description of 11 new patients. JIMD Rep. 2019;44:85-92. doi:10.1007/8904_2018_128
Yuste-Checa P, Vega AI, Martin-Higueras C, et al. DPAGT1-CDG: functional analysis of disease-causing pathogenic mutations and role of endoplasmic reticulum stress. PLoS ONE. 2017;12(6):e0179456. doi:10.1371/journal.pone.0179456
Gwack Y, Srikanth S, Feske S, et al. Biochemical and functional characterization of Orai proteins. J Biol Chem. 2007;282(22):16232-16243. doi:10.1074/jbc.M609630200
Feske S, Gwack Y, Prakriya M, et al. A mutation in Orai1 causes immune deficiency by abrogating CRAC channel function. Nature. 2006;441(7090):179-185. doi:10.1038/nature04702
Zhang SL, Yu Y, Roos J, et al. STIM1 is a Ca2+ sensor that activates CRAC channels and migrates from the Ca2+ store to the plasma membrane. Nature. 2005;437(7060):902-905. doi:10.1038/nature04147
Bohm J, Laporte J. Gain-of-function mutations in STIM1 and ORAI1 causing tubular aggregate myopathy and Stormorken syndrome. Cell Calcium. Sep 3 2018;76:1-9. doi:10.1016/j.ceca.2018.07.008
Endo Y, Noguchi S, Hara Y, et al. Dominant mutations in ORAI1 cause tubular aggregate myopathy with hypocalcemia via constitutive activation of store-operated Ca(2)(+) channels. Hum Mol Genet. 2015;24(3):637-648. doi:10.1093/hmg/ddu477
Misceo D, Holmgren A, Louch WE, et al. A dominant STIM1 mutation causes Stormorken syndrome. Hum Mutat. 2014;35(5):556-564. doi:10.1002/humu.22544
Morin G, Bruechle NO, Singh AR, et al. Gain-of-function mutation in STIM1 (P.R304W) is associated with Stormorken syndrome. Hum Mutat. 2014;35(10):1221-1232. doi:10.1002/humu.22621
Netzer C, Bohlander SK, Hinzke M, Chen Y, Kohlhase J. Defining the heterochromatin localization and repression domains of SALL1. Biochim Biophys Acta. 2006;1762(3):386-391. doi:10.1016/j.bbadis.2005.12.005 S0925-4439(05)00183-3 [pii]
Lacruz RS, Feske S. Diseases caused by mutations in ORAI1 and STIM1. Ann N Y Acad Sci. 2015;1356(1):45-79. doi:10.1111/nyas.12938
Silva-Rojas R, Laporte J, Bohm J. STIM1/ORAI1 loss-of-function and gain-of-function mutations inversely impact on SOCE and calcium homeostasis and cause multi-systemic mirror diseases. Front Physiol. 2020;11:604941. doi:10.3389/fphys.2020.604941
Bohm J, Chevessier F, Koch C, et al. Clinical, histological and genetic characterisation of patients with tubular aggregate myopathy caused by mutations in STIM1. J Med Genet. 2014;51(12):824-833. doi:10.1136/jmedgenet-2014-102623
Silva-Rojas R, Charles AL, Djeddi S, Geny B, Laporte J, Bohm J. Pathophysiological effects of overactive STIM1 on murine muscle function and structure. Cell. 2021;10(7):1730. doi:10.3390/cells10071730
Silva-Rojas R, Treves S, Jacobs H, et al. STIM1 over-activation generates a multi-systemic phenotype affecting the skeletal muscle, spleen, eye, skin, bones and immune system in mice. Hum Mol Genet. 2019;28(10):1579-1593. doi:10.1093/hmg/ddy446
Maggi L, Mantegazza R. Treatment of myasthenia gravis: focus on pyridostigmine. Clin Drug Investig. 2011;31(10):691-701. doi:10.2165/11593300-000000000-00000
Saito M, Ogasawara M, Inaba Y, et al. Successful treatment of congenital myasthenic syndrome caused by a novel compound heterozygous variant in RAPSN. Brain Dev. 2022;44(1):50-55. doi:10.1016/j.braindev.2021.09.001
Jiang K, Zheng Y, Lin J, et al. Diverse myopathological features in the congenital myasthenia syndrome with GFPT1 mutation. Brain Behav. 2022;12(2):e2469. doi:10.1002/brb3.2469
Ma Y, Xiong T, Lei G, et al. Novel compound heterozygous variants in the GFPT1 gene leading to rare limb-girdle congenital myasthenic syndrome with rimmed vacuoles. Neurol Sci. 2021;42(8):3485-3490. doi:10.1007/s10072-020-05021-0
Selcen D, Shen XM, Milone M, et al. GFPT1-myasthenia: clinical, structural, and electrophysiologic heterogeneity. Neurology. 2013;81(4):370-378. doi:10.1212/WNL.0b013e31829c5e9c
Messina S, Hartley L, Main M, et al. Pilot trial of salbutamol in central core and multi-minicore diseases. Neuropediatrics. 2004;35(5):262-266. doi:10.1055/s-2004-821173
Schreuder LT, Nijhuis-van der Sanden MW, de Hair A, et al. Successful use of albuterol in a patient with central core disease and mitochondrial dysfunction. J Inherit Metab Dis. 2010;33(Suppl 3):S205-S209. doi:10.1007/s10545-010-9085-7
