MUSK and myasthenia gravis: Efgartigimod is a targeted FcRn antagonist that promotes the clearance of pathogenic antibodies by blocking the interaction between IgG and FcRn (6).The drug has been approved for the treatment of MG patients with positive AChR antibodies, but its efficacy in other subtypes of MG, such as MG patients with positive MuSK antibodies and DSP-MG, remains unknown (7).