myasthenia gravis: a chronic progressive disease characterized by chronic fatigue and muscular weakness (especially in the face and neck); caused by a deficiency of acetylcholine at the neuromuscular junctions
autoimmune disease: any of a large group of diseases characterized by abnormal functioning of the immune system that causes your immune system to produce antibodies against your own tissues
junk mail: third-class mail consisting of advertising and often addressed to `resident' or `occupant'