Multiple sclerosis (MS) and Guillain-Barré syndrome (GBS) are both diseases of the nervous system. They’re not the same, but they do have a lot of similarities.
For example, both MS and GBS are autoimmune diseases, which means they cause your body's immune system to attack its own tissues. They both start when the immune system attacks and damages the layer of insulation that surrounds nerves. Called myelin, this substance also helps nerves transmit information.