Passive and active immunization models of MuSK-Ab positive myasthenia: Electrophysiological evidence for pre and postsynaptic defects

►First detailed study of neuromuscular transmission in models of muscle specific kinase myasthenia. ►First comparison between acetylcholine receptor and muscle specific kinase myasthenias. ►First comparison of active and passive transfer models of these forms of myasthenia. ►Presynaptic compensatory change occurs in acetylcholine receptor antibody models. ►Lack of compensatory modification in muscle specific kinase myasthenia may underlie severity.