Seronegative myasthenia gravis: Comparison of neurophysiological picture in MuSK+ and MuSK- patients

L. Padua, P. Tonali, I. Aprile, P. Caliandro, E. Bartoccioni, A. Evoli

Research output: Contribution to journalArticlepeer-review


The aim of this study was to compare the neurophysiological and clinical pictures of a large sample of seronegative myasthenia gravis (SNMG) patients with and without anti-MuSK antibodies. Fifty-two consecutive SNMG patients were retrospectively evaluated. They had undergone an extended neurophysiological evaluation: repetitive nerve stimulation (RNS), single fiber EMG (SFEMG), and electromyography (EMG) with nerve conduction study. A muscle biopsy was performed in 11 of 52 patients, the edrophonium test in 44 of 52 patients and anti-AChR antibodies and anti-MuSK antibodies were tested in all patients. Anti-MuSK antibodies were detected in 25 SNMG patients (48.1%). The number of women in the MuSK+ group was significantly higher (P = 0.01) than in the MuSK- group. Seronegative MuSK+ patients are more severely affected and the deficit often involves the bulbar and the respiratory muscles. No statistically significant differences were observed in the edrophonium test between MuSK+ and MuSK- groups. The RNS test was abnormal in a significantly higher number of MUSK- patients than MUSK+ patients (P <0.00001). With regard to SFEMG data, MuSK- patients were characterized to have more severe neurophysiological pattern. Our observations showed several differences between the clinical and neurophysiological pictures ofq2 MUSK+ and MUSK- patients.

Original languageEnglish
Pages (from-to)273-276
Number of pages4
JournalEuropean Journal of Neurology
Issue number3
Publication statusPublished - Mar 2006


  • Musk antibody
  • Myasthenia gravis
  • Neurophysiology

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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