MUSK and myasthenia gravis: These autoAbs are found in approximately 85% of the patients with generalized MG (AChR-MG) [1], [2], while the remaining ∼15% of MG patients have autoAbs to additional NMJ proteins: MuSK (Muscle-Specific Kinase) [7]–[9] and LRP4 (lipoprotein receptor-related protein) [10], [11] or not yet detectable autoAbs [12].