Rinsho Shinkeigaku (Clinical Neurology)


Standard treatment for late-onset myasthenia gravis in Japan

Masakatsu Motomura, M.D., Ph.D.

Department of Clinical Neuroscience and Neurology, Graduate School of Biomedical Scineces, Nagasaki University

Myasthenia gravis (MG) is caused by the failure of neuromuscular transmission mediated by autoantibodies against acetylcholine receptors (AChR) and muscle-specific receptor tyrosine kinase (MuSK). These seropositivity rates in AChR positive and MuSK positive MG in Japan are 80-85% and 5-10%, respectively. The incidence of lateonset MG has been increasing all over the world. A nationwide epidemiological survey in Japan also revealed that the rates of late-onset MG (onset after 50 years) had increased from 20% in 1987 to 42% in 2006. In 2010, a guideline for standard treatments in late-onset MG was published from Japanese Scoiety of Neurological Therapeutics. Based on individual experiences and the limited evidence, epidemiological characteristics of MG onset age, clinical features, and the standard treatment for late-onset patients are included in it. In this guideline summary, the ocular form was more frequent in late-onset compared to early-onset group, the indication of thymectomy in lateonset MG is less than that of early-onset MG and the combination of corticosteroids and immunosuppressive agents are recommended in order to reduce doses of corticosteroids in late-onset MG.
Full Text of this Article in Japanese PDF (597K)

(CLINICA NEUROL, 51: 576|582, 2011)
key words: Myasthenia gravis (MG), late-onset MG, standard treatment, acetylcholine receptors (AChR), muscle-specific receptor tyrosine kinase (MuSK)

(Received: 30-May-11)