Some people may have one or two attacks and then be symptom-free for the rest of their lives. Others may have a slowly progressive course with no remissions.it is most often diagnosed in those aged 20 to 40 although it has been found in people younger and older. The average age of diagnosis is 30. Three women have MS for every two men. At the present time it is not known what causes MS although there are a number of theories.
Some researchers believe that the disease is viral in nature and acquired during childhood.
Other researchers report evidence that MS may be what is called an autoimmune disease. Something causes the body to become allergic to itself, and the immune mechanisms that usually reject foreign invaders such as bacteria and viruses react against its own body. This doesn't mean that MS is inherited but that certain factors in a persona white blood cell type may bring about a greater chance of developing the disease. It is possible that a common virus may trigger the body's immune system to attack and damage central nervous system myelin in a genetically susceptible person.