Heterogeneity of Ocular Myasthenia Gravis: Potential Subgroups

ABSTRACT Objectives The clinical features of ocular myasthenia gravis (OMG) appeared to be diverse in terms of age at onset and autoantibody titers, suggesting the possibility of the existence of multiple subgroups. To characterize each subgroup, we investigated the clinical characteristics of Japanese patients with OMG. Methods We performed a retrospective cross‐sectional survey of OMG patients from eight hospitals in Japan. Clinical information was obtained, including age at onset, autoantibodies including anti‐acetylcholine receptor (AChR) titers, complications, and clinical course. Results In total, 135 patients with OMG (67 men, 68 women) were included. There appeared to be three peaks in onset age; one was below 5 years old, and others at 45–49 and 60–64 years old. Moreover, 20.7% developed OMG after 65 years old. Anti‐AChR antibodies were detected in 77.6%, among which 31.3% had rather low titers (0.2–1.9 nmol/L), while 12 patients had very high titers (50–1720 nmol/L). There were thymic abnormalities and/or autoimmune complications, as seen in patients with generalized MG. Conclusions The clinical features of OMG appeared to be heterogeneous, with several potential subgroups including childhood onset, a subset with very high antibody titers, and an elderly onset group.