Serological And Clinical Study Of 391 Chinese Myasthenia Patients

Ocular and childhood cases of myasthenia gravis (MG) appear relatively more common in Oriental than in Caucasian populations, but there have been no comprehensive serological studies on patients from China. We studied 391 unselected cases of MG attending Tongji Hospital in WuHan during a one year period. The duration of disease ranged from a few months to 47 years. The male to female ratio was 0.8. 50% of the patients were children (under 15 years), and age at onset showed a single peak at between 5 and 10 years of age. Overall, 64% of the children and 66% of the adults were positive for acetylcholine receptor (AChR) antibodies. Of the 43 patients with generalized MG without AChR antibodies, only one had MuSK antibodies (2.5%) and two had VGCC antibodies indicating probable Lambert Eaton myasthenic syndrome. Taking only those MG patients with durations of two or more years, 94/126 (75%) of the children had ocular MG and of these 68 (72%) had AChR antibodies. Whereas only 24/85 (28%) of the adults had ocular MG and of these 12 (50%) had AChR antibodies. Thymoma was evident by MRI in 1.5% of children and 20% of adults. Overall, the results demonstrate that childhood onset of ocular weakness is even more common than in previous reports from Pacific countries, and a high proportion of these patients have AChR antibodies, confirming the diagnosis of MG. By contrast, patients presenting in later age appears to be very uncommon in comparison with recent studies in Caucasian populations.