Multiple Sclerosis (MS) is the most common neurological disorder causing disability in young adults affecting approximately 1 in 1.000 people in western countries. The clinical manifestations usually begin at the age of 20 to 40 years with a median age of 28 years at onset with acute episodes of neurological dysfunction, followed by periods of partial or complete remission and clinical stability in between relapses. This relapsing-remitting phase (RR-MS) of the disease is usually followed by progressive clinical disability (secondary progressive phase, SP-MS).