MUSK and myasthenia gravis: In fact, these results of our classification statistically performed are consistent with a recently reported classification of MG by Gilhus et al. [16, 17], which included the following classifications: early-onset MG; late-onset MG; thymoma-associated MG; MuSK-Ab positive MG; lipoprotein-related protein 4 (LRP4)-Ab positive MG; seronegative MG; and ocular MG.