Myasthenia gravis with muscle specific kinase antibodies mimicking amyotrophic lateral sclerosis

Maartje G. Huijbers*, Erik H. Niks, Rinse Klooster, Marianne de Visser, Jan B. Kuks, Jan H. Veldink, Pim Klarenbeek, Philip Van Damme, Marc H. de Baets, Silvere M. van der Maarel, Leonard H. van den Berg, Jan J. Verschuuren

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    24 Citations (Scopus)


    Muscle-specific kinase (MuSK) myasthenia gravis (MG) is hallmarked by the predominant involvement of bulbar muscles and muscle atrophy. This might mimic amyotrophic lateral sclerosis (ALS) presenting with bulbar weakness. We encountered four cases of MuSK MG patients with an initial misdiagnosis of ALS. We analyzed the clinical data of the four misdiagnosed MuSK MG patients, and investigated the presence of MuSK autoantibodies in a group of 256 Dutch bulbar-onset ALS patients using a. recombinant MuSK ELISA and a standard MuSK radioimmunorecipitation assay. Clues for changing the diagnosis were slow progression, clinical improvement, development of diplopia and absence of signs of upper motor neuron involvement. No cases of MuSK MG were identified among a group of 256 bulbar ALS patients diagnosed according to the revised El Escorial criteria. A misdiagnosis of ALS in patients with MuSK MG is rare. We recommend to carefully consider the diagnosis of MuSK MG in patients presenting with bulbar weakness without clear signs of upper motor neuron dysfunction. (C) 2016 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)350-353
    Number of pages4
    JournalNeuromuscular disorders
    Issue number6
    Publication statusPublished - Jun-2016


    • Amyotrophic lateral sclerosis
    • Myasthenia gravis
    • MuSK
    • Neuromuscular junction
    • IgG4
    • MUSK

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