Table 1.
Clinical subgroups of myasthenia gravis (modified from [4]).
| MG Subgroup | Clinical Characteristics | Antigen | Thymus Pathology | IgG Subclass |
|---|---|---|---|---|
| Early onset MG (EOMG) | Age of onset <50, sex ratio (F:M) 3:1, genetic association with HLA-B8, A1, and DRw3 | AChR | Thymic lymphofollicular hyperplasia | IgG1, IgG |
| Late onset MG (LOMG) | Age of onset >50, sex ratio (F:M) 1:1.5, genetic association with HLA-A3, B7, and DRw2 | AChR | Normal thymus (age-related thymus atrophy) | IgG1, IgG3 |
| Thymoma associated MG (TAMG) | Paraneoplastic MG, non-pathogenic antibodies against striated muscle, titin, ryanodine receptor | AChR | Thymoma | IgG1, IgG3 |
| Ocular MG (OMG) | Restricted to ocular muscles, low AChR titres | AChR | Variable, no lymphoid follicles | IgG1, IgG3 |
| MuSK MG | Severe phenotype, respiratory, and bulbar muscle weakness, sex ratio (F:M) up to 9:1, genetic association with HLA-DR14-DQ5 | MuSK | Normal thymus | IgG4 |
| Lrp4 MG | Mild phenotype, sex ratio (F:M) 2.5:1 | Lrp4 | Variable (normal, thymoma, thymic lymphofollicular hyperplasia) | IgG1, IgG2 |
| Agrin MG | Generalized weakness, often also additional AChR, MuSK, or Lrp4 antibodies, associated with severe weakness | Agrin | No thymoma (few studies) | N/A |
| Transient neonatal MG (TNMG) | Mild symptoms, onset at birth, remission after days to months | AChR, MuSK | maternal IgG | |
| Fetal myasthenia gravis | Reduced fetal mobility, arthrogryposis congenital (AMC), very severe, risk of fetal death | Fetal AChR γ subunit | maternal IgG |