DEFINITION
Myasthenia gravis (MG) is an autoimmune disorder involving the neuromuscular junction (NMJ) in which there is fatigue of the skeletal musculature, which is potentially life-threatening. The weakness of the muscles tends to fluctuate. It affects the voluntary muscles of the body. It mostly affects the eyes, mouth, throat, arms, and legs. It most often affects adults but can sometimes happen in children.