MG is a heterogeneous disease, the clinical variability of which allows for patients’ stratification into distinct disease subgroups according to the following features: (i) autoantibodies profile (AChR-, MuSK-, LRP4-, or triple seronegative MG); (ii) symptoms’ distribution (ocular versus generalized MG); (iii) age at disease onset (early-onset, EOMG, versus late-onset, LOMG: <50 versus >50 years); and (iv) presence or absence of thymoma [2,10]. This evidence concerns the gene MUSK and myasthenia gravis.