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Clinical comparison of muscle‐specific tyrosine kinase (MuSK) antibody‐positive and ‐negative myasthenic patients
Author(s) -
Zhou Lan,
McConville John,
Chaudhry Vinay,
Adams Robert N.,
Skolasky Richard L.,
Vincent Angela,
Drachman Daniel B.
Publication year - 2004
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.20069
Subject(s) - myasthenia gravis , antibody , medicine , weakness , muscle weakness , acetylcholine receptor , tyrosine kinase , immunology , gastroenterology , receptor , surgery
We assayed cryopreserved sera from 38 acetylcholine receptor (AChR) antibody‐negative patients with myasthenia gravis (MG) who were followed clinically for muscle‐specific tyrosine kinase (MuSK) antibodies and analyzed and compared their clinical characteristics. None of 13 sera from patients with purely ocular MG were positive. Sera from 10 of 25 patients (40%) with generalized MG were positive for MuSK antibodies. The age at onset of myasthenic symptoms was significantly earlier in MuSK antibody‐positive patients ( P = 0.02). MuSK antibodies were present in AChR antibody‐negative patients of either gender, with virtually identical prevalence in women (41.2%) and men (37.5%). The distribution of weakness more commonly involved neck muscles in MuSK antibody‐positive patients, and limb muscles in MuSK antibody‐negative patients. Patients responded to immunosuppressive treatment regardless of whether MuSK antibody was present. We conclude that MuSK antibodies are present and diagnostically useful in a subset of myasthenic patients without AChR antibodies. Although the distribution of weakness differs somewhat depending on whether MuSK antibodies are present, responses to anticholinesterase and immunosuppressive treatments are similar. © 2004 Wiley Periodicals, Inc. Muscle Nerve 30: 55–60, 2004