The fact that all of the alleles positively associated (B*08, B*47, B*73, A*02:36, B*44:27, B*57:02, DRB1*14:54 and DRB1*16:01) with MG remained significantly associated with RAch+MG, regardless of the patients’ clinical and thymic heterogeneity, suggests that these alleles might play an etiopathogenic role in the tolerance breakdown, which leads to the specific production of autoantibodies. This evidence concerns the gene HLA-DRB1 and myasthenia gravis.