In the remaining MG patients, antibodies against other components of the postsynaptic membrane can be found, such as muscle-specific tyrosine kinase antibody (MuSK-Abs) in 5% of patients3, 4, 5, 6and anti-low-density lipoprotein receptor-related protein 4 antibody (LRP4-Abs) with a variable incidence.2, 6, 7. Here, MUSK is linked to myasthenia gravis.