Low frequency of MuSK antibody in generalized seronegative myasthenia gravis among Chinese

Approximately 15% of 1patients with generalized myasthenia gravis (MG) lack detectable circulating antibodies to the acetylcholine receptor (AChRAb), referred to as seronegative MG (SNMG). During the last 3 years, antibodies against muscle-specific tyrosine kinase (MuSKAb) were found in about 40 to 70% of patients with SNMG.1–5⇓⇓⇓⇓ We report the first MuSKAb survey among Chinese patients with SNMG and compare the features of MuSKAb-positive patients with those of Caucasian patients. During last 10 years, we collected data from 774 myasthenic patients (389 with the ocular type and 385 generalized type) at the Shin Kong Wu Ho-Su Memorial Hospital. Among patients with generalized MG, 38 (9.8%) were seronegative for AChRAb. We enrolled 26 of these patients, who had been monitored regularly; 20 were women and 6 were men (table). Twenty patients were in Osserman stage IIa, four were in IIb, and two patients were in stage III. Limb weakness was the most common …