Table 1

Comparison of different subgroups of myasthenia gravis

SubgroupProportion of all myasthenia gravis (%)Age of onset (years)Sex (M:F)Clinical featuresAChR antibodiesMuSK antibodiesThymus
Ocular myasthenia gravis15–254–903:2Ptosis, ophthalmoplegiaApprox 50%Very rareMild hyperplasia (30%)
Early onset AChR-myasthenia gravis20–252–401:3Ptosis, ophthalmoplegia, generalised weaknessApprox 85%AbsentHyperplasia (>80%)
Late onset AChR-myasthenia gravis30–40>403:2Ptosis, ophthalmoplegia, generalised weaknessApprox 60%AbsentAtrophy
MuSK-myasthenia gravis5–82–701:3Predominant ocular, facial and bulbar weaknessAbsent100%Normal or atrophy
Seronegative myasthenia gravis5–1010–701:2Ptosis, ophthalmoplegia, generalised weaknessAntibodies against clustered AChR in 50–60%AbsentMild hyperplasia
  • AChR, acetylcholine receptor; MuSK, muscle specific tyrosine kinase.