Multiple Sclerosis

Multiple sclerosis (abbreviated MS, also known as disseminated sclerosis or encephalomyelitis disseminata) is an autoimmune condition in which the immune system attacks the central nervous system, leading to demyelination. Disease onset usually occurs in young adults, and it is more common in women. It has a prevalence that ranges between 2 and 150 per 100,000. MS was first described in 1868 by Jean-Martin Charcot.

MS affects the areas of the brain and spinal cord known as the white matter, destroying a fatty layer called the myelin sheath, which wraps around nerve fibers and electrically insulates them. When myelin is lost, the axons of neurons can no longer effectively conduct action potentials. The name multiple sclerosis refers to the scars (scleroses better known as plaques or lesions) in the white matter. Although much is known about the mechanisms involved in the disease process, the cause remains unknown. Theories include genetics or infections. Different environmental risk factors have also been found.