My-as-theen-ee-a Grav-us) comes from the Greek and Latin words meaning "grave muscular weakness." The most common form of MG is a chronic autoimmune neuromuscular disorder that is characterized by fluctuating weakness of the voluntary muscle groups. The prevalence of MG in the United States is estimated to be about 20/100,000 population. However, MG is probably under diagnosed and the prevalence may be higher. Myasthenia Gravis occurs in all races, both genders, and