What causes Multiple Sclerosis?

It is not known what causes MS. However, it is believed to be an autoimmune disease, meaning the body?s defense mechanism begins to attack parts of the body, as though it were foreign. In MS antibodies attack the myelin sheath. The myelin sheath is a fatty substance that insulates and protects nerve fibers in much the same way that the plastic around electrical wires insulates and protects wires.

• Heredity. Multiple sclerosis is more common in people of Northern European descent. However, children of people affected by MS have less than a 5% risk of developing the disease during their lifetime. Researchers believe that in addition to heredity certain environmental triggers must also be present for the disease to develop.
• Environmental factors. Some studies suggest certain viruses or bacteria may cause MS, such as the Epstein-Barr virus, the virus known to cause infectious mononucleosis. MS may not develop for 10 or more years after the infection.
• Geographical factors. For reasons not yet known, Multiple sclerosis is more common in countries with temperate climates, including Europe, southern Canada, northern United States, and southeastern Australia.