The cause of multiple sclerosis is unknown. It’s considered an autoimmune disease in which the body’s immune system attacks its own tissues. In the case of MS , this immune system malfunction destroys the fatty substance that coats and protects nerve fibers in the brain and spinal cord (myelin).Multiple sclerosis, or MS, is a long-lasting disease that can affect your brain, spinal cord, and the optic nerves in your eyes. It can cause problems with vision, balance, muscle control, and other basic body functions. The effects are often different for everyone who has the disease.Multiple sclerosis is not fatal, except in very rare circumstances. During advanced stages of disease progression, it is possible to die from complications related to MS (such as infections or pneumonia). … In fact, the leading causes of death in the MS community are the same as the general population.