MUSK and myasthenia gravis: Approximately 10%–15% of MG patients with anti‐AChR antibody‐positive (AChR‐MG) and most anti‐MuSK antibody‐positive MG (MuSK‐MG) patients do not respond to standard treatments, such as glucocorticoids and immunosuppressants (IS) like azathioprine, tacrolimus, or mycophenolate mofetil.