Gender and Ethnicity Based Differences in Clinical and Laboratory Features of Myasthenia Gravis

Background. Previous reports describe ethnicity based differences in clinical and laboratory features between Caucasians and African Americans with myasthenia gravis. However, it is not known whether these findings apply to other ethnicities. Methods. Retrospective analysis of all patients treated for myasthenia gravis during a three-year period at a community based medical center. Results. A total of 44 patients were included, including 19 of Hispanic, 16 of African American, 6 of Caucasian, and 3 of Asian ethnicities. Female gender was more common among those with Hispanic, Asian, and African American ethnicities compared to Caucasian ethnicity (p = 0.029). Anti-acetylcholine receptor antibody subtypes demonstrated no significant ethnicity based differences in either generalized or ocular myasthenia gravis. A trend was noted towards greater frequency of blocking antibodies among Hispanics (52.6%) compared to African American (37.5%) and Caucasian (33.3%) patients (p = 0.059). Generalized but not ocular myasthenia patients showed greater frequency of anti-muscle specific kinase antibodies in Asians and Hispanics compared to African Americans and Caucasians (p = 0.041). Conclusions. The results of this study support the existence of ethnicity based differences in clinical and laboratory features of myasthenia gravis. Further study of genetic factors influencing clinical features of myasthenia gravis is indicated.