title: Chronic Myopathy Associated With Anti-Signal Recognition Particle Antibodies Can Be Misdiagnosed As Facioscapulohumeral Muscular Dystrophy.
abstract: OBJECTIVE
  To report cases of chronic autoimmune necrotizing myopathy with anti-signal recognition particle antibodies (anti-SRP myopathy) initially misdiagnosed as muscular dystrophy, in particular, facioscapulohumeral muscular dystrophy (FSHD).
  
  
  METHODS
  Medical records of patients with anti-SRP myopathy in our institution were retrospectively reviewed.
  
  
  RESULTS
  All 6 patients were initially diagnosed with muscular dystrophy because of the long-term clinical course and lack of inflammation on biopsy; 5 were diagnosed with FSHD based on a winged scapula. However, the following features suggested an alternative diagnosis, leading to anti-SRP antibody measurement: (1) lack of family history, (2) lack of facial involvement and asymmetry, (3) prominent dysphagia, and (4) profuse spontaneous activities on needle electromyography. All patients showed improvement with immunomodulating therapy.
  
  
  CONCLUSIONS
  Anti-SRP antibody measurement should be considered in patients diagnosed with FSHD if they present with diagnostic hallmarks of anti-SRP myopathy listed above, to avoid oversight of this potentially treatable disorder.
authors.affiliation: *Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan; †Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan; ‡Department of Neurology, Keio University School of Medicine, Tokyo, Japan; §Department of Neurology, Toranomon Hospital, Tokyo, Japan; ¶Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan; ‖Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan; **Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan; and ††Medical Genome Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Ikeda
authors.forename: Madoka
authors.initials: M
authors.lastname: Mori-Yoshimura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sonoo
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kondo
authors.forename: Harumasa
authors.initials: H
authors.lastname: Nakamura
authors.forename: Kana
authors.initials: K
authors.lastname: Mitsuhashi
authors.forename: Meiko Hashimoto
authors.initials: MH
authors.lastname: Maeda
authors.forename: Jun
authors.initials: J
authors.lastname: Shimizu
authors.forename: Yukiko K
authors.initials: YK
authors.lastname: Hayashi
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oya
authors.forename: Miho
authors.initials: M
authors.lastname: Murata
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000276:immunology*; D003951:Diagnostic Errors; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000276:immunology* / Q000473:pathology; D009135:Muscular Diseases / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D012189:Retrospective Studies; D018271:Signal Recognition Particle / Q000276:immunology*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D018271:Signal Recognition Particle