RGS13, the smallest member of the RGS (G protein signal transduction regulator) family mainly expressing in B lymphocytes and mast cells (MC), was known to be related to immune-related diseases including human B lymphoma, allergic asthma and myasthenia gravis, and function as attenuating G protein mediated signal transduction (41, 42). This evidence concerns the gene RGS13 and myasthenia gravis.