The Facts
Myasthenia gravis is an autoimmune disease of the neuromuscular junction,
the contact point between nerves and muscles. For some unknown reason, the
body's immune system, which normally helps fight infections, attacks the acetylcholine
receptors found on muscles. These receptors normally receive a chemical
called acetylcholine, which is released by the nerves at the neuromuscular
junction (the point of contact between nerve and muscle) and signals the
muscles to contract. Once these receptors are damaged, the muscles cannot respond
to the nerve signals and the muscles become weak.
Myasthenia gravis is almost twice as common in women as in men. It is most
commonly found in women under 40 and men over 60. However, it can occur at any
age. Children are very unlikely to suffer from this disease. People from all
continents are equally susceptible. A closely related disease called congenital
myasthenic syndrome is genetically inherited. Myasthenia gravis itself probably
has a genetic component, but the children of people with this condition are
only slightly more likely than average to suffer from autoimmune disease.
Myasthenia gravis is a serious condition, but not usually a life-threatening
one. However, in severe cases, the chest muscles can become so weak that patients
have trouble breathing on their own and may require a ventilator for a few days
to a few weeks.