Myasthenia gravis 重症肌无力

Myasthenia gravis (MG) is a neuromuscular disease that leads to fluctuating muscle weakness and fatigue. In the most common cases, muscle weakness is caused by circulating antibodies that block nicotinic acetylcholine receptors at the postsynaptic neuromuscular junction. By blocking the ability of the neurotransmitter acetylcholine to bind to these receptors in the muscle, these antibodies keep motor neurons from signaling the muscle to contract. Alternatively, in a much rarer form, muscle weakness is caused by a genetic defect in some portion of the neuromuscular junction that is inherited at birth as opposed to developing through passive transmission from the mother's immune system at birth or through autoimmunity later in life.