Myastenia grafis (MG) is a disease caused by disordered neuromuscular transmission on neuromuscular plate. Auto-antibodies to postsynaptic acetylcholine receptors (AChR) are detectable in the serum of 80-90% of patients with generalized MG.
Muscle-specific receptor tyrosine kinase auto-antibodies (AMUSK) in patients with myasthenia gravis without acetylcholine receptor antibodies are found in 7% of cases.