Chronic Myopathy Associated with Anti-Signal Recognition Particle Antibodies Can Be Misdiagnosed As Facioscapulohumeral Muscular Dystrophy

Kensuke Ikeda, Madoka Mori-Yoshimura, Toshiyuki Yamamoto, Masahiro Sonoo, Shigeaki Suzuki, Yoshiyuki Kondo, Harumasa Nakamura, Kana Mitsuhashi, Meiko Hashimoto Maeda, Jun Shimizu, Yukiko K. Hayashi, Ichizo Nishino, Yasushi Oya, Miho Murata

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Abstract

Objectives: 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.

Original languageEnglish
Pages (from-to)197-206
Number of pages10
JournalJournal of Clinical Neuromuscular Disease
Volume17
Issue number4
DOIs
Publication statusPublished - 2016 Jun 1

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Keywords

  • anti-signal recognition particle antibody
  • dysphagia
  • facioscapulohumeral muscular dystrophy
  • winged scapulae

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

Cite this

Ikeda, K., Mori-Yoshimura, M., Yamamoto, T., Sonoo, M., Suzuki, S., Kondo, Y., Nakamura, H., Mitsuhashi, K., Maeda, M. H., Shimizu, J., Hayashi, Y. K., Nishino, I., Oya, Y., & Murata, M. (2016). Chronic Myopathy Associated with Anti-Signal Recognition Particle Antibodies Can Be Misdiagnosed As Facioscapulohumeral Muscular Dystrophy. Journal of Clinical Neuromuscular Disease, 17(4), 197-206. https://doi.org/10.1097/CND.0000000000000115