MUSK and myasthenia gravis: These can help explain the reports showing both pre- and post-synaptic defects in MuSK antibody-positive MG patients (Niks et al., 2010) and animal models (Cole et al., 2008; Klooster et al., 2012; Mori et al., 2012; Richman et al., 2012; Viegas et al., 2012).