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

Abstract

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 of MUSK+ and MUSK- patients.

• Authors: L Padua, P Tonali, I Aprile, P Caliandro, E Bartoccioni, A Evoli
• Journal: European journal of neurology (Eur J Neurol) Vol. 13 Issue 3 Pg. 273-6 (Mar 2006) ISSN: 1351-5101 [Print] England
• PMID: 16618345 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Antibodies
• Receptors, Cholinergic
• Serotonin
• MUSK protein, human
• Receptor Protein-Tyrosine Kinases

Topics

• Adult
• Antibodies (metabolism)
• Electric Stimulation (methods)
• Electromyography (methods)
• Evoked Potentials (physiology, radiation effects)
• Female
• Humans
• Male
• Middle Aged
• Myasthenia Gravis (classification, immunology, metabolism, physiopathology)
• Neural Conduction (physiology, radiation effects)
• Reaction Time (physiology, radiation effects)
• Receptor Protein-Tyrosine Kinases (immunology)
• Receptors, Cholinergic (immunology)
• Serotonin (metabolism)
• Statistics, Nonparametric