Myasthenia gravis, or MG is an autoimmune disease, which means that the body’s immune system mistakenly attacks it. In the case of myasthenia gravis, the immune system attacks the muscles and the nerves that control them. These muscles are under the person’s control, such as the muscles that move the arms and legs. Though it is like other autoimmune diseases in that it is found more often in women, MG also affects men. Myasthenia gravis usually strikes women under 40 and men over 60 and occurs in 20 per 100,000 people. As of 2018 there is no cure for myasthenia gravis.The nerves that control the muscles are in turn controlled by a neurotransmitter called acetylcholine. A neurotransmitter is a chemical that sends messages to and from the nerve cells. In the case of myasthenia gravis, the body produces antibodies that destroy the acetylcholine receptors in the nerves. Some doctors believe these antibodies are made in the patient’s thymus gland, which is found in the chest. This gland is usually small and sometimes nonexistent in adults, but in people with myasthenia gravis it’s large and might contain benign tumors. Sometimes, when the thymus is removed the symptoms and signs of myasthenia gravis resolve.
