MUSK and myasthenia gravis: Subsequent experiments carried out on different animal models—either passively immunized with MG patients’ plasma or actively immunized with purified recombinant MuSK—showed clinical symptoms and/or impaired neuromuscular transmission consistent with the myasthenic phenotype, including muscle weakness and fatigability, reduction of endplate AChR numbers, and reduction of endplate potential (EPP) and miniature EPP amplitudes (Shigemoto et al., 2006; Cole et al., 2010; Klooster et al., 2012; Viegas et al., 2012).