Experience with patients with anti-MUSK antibody positive myasthenia gravis.

The association of muscle tyrosine kinase (Musk) antibody with recurrent bulbar weakness in acetylcholine receptor antibody (Ach-R Ab) negative myasthenia gravis (MG) has been well documented. We describe 2 patients, a middle aged man and a 9-year-old girl, both seronegative for Ach R antibody who had recurrent bulbar weakness and MUSK antibody positivity. Patients made a full recovery from the acute episode with intravenous immunoglobulin (IV Ig) therapy.