Myasthenia gravis: population differences in disease expression and acetylcholine receptor antibody titers between Chinese and Caucasians.

Clinical features and anti-acetylcholine receptor (AChR) titers were compared in Chinese (n = 258) and Caucasian (n = 258) myasthenia gravis populations. The former had more early onset and ocular cases, lacked the Caucasian late onset peak, and had fewer severe cases. The distribution of anti-AChR titers was broadly similar in the two populations, and their sera reacted equally well with AChR in both races. The significantly lower (chi 2 = 14.6; p less than 0.001) median anti-AChR titer in the Chinese population can be accounted for by the higher frequency of ocular cases and lower frequency of moderate or severely affected cases.