Multiple Sclerosis

Multiple sclerosis (or MS) is a chronic, often disabling disease that attacks the central nervous system (CNS) which is made up of the brain, spinal cord, and optic nerves. Symptoms may be mild, such as numbness in the limbs; or severe, such as paralysis or loss of vision. The progress, severity, and specific symptoms of MS are unpredictable and vary from one person to another.


While there is not currently a cure for MS, there are multiple treatment options available to address symptoms. All of these products can alter the course of the disease by decreasing the number and severity of relapses, by slowing the progression of the disease, and by reducing the accumulation of new lesions.

Types of MS

RRMS: Relapsing-Remitting MS

Clearly defined attacks lasting from days to weeks, with full recovery or with some remaining neurological symptoms and deficits upon recovery. Periods between relapses are stable and absent of disease progression. This is by far the most common form of the disease.

SPMS: Secondary Progressive MS

Begins initially with a relapsing-remitting course that becomes consistently progressive and includes occasional relapses and minor remission. Deficits are accumulated without recovery between attacks.

PPMS: Primary Progressive

Progression of level of disability from the onset without any distinct relapses of remissions. Temporary, minor improvements may be experienced.

PRMS: Progressive Relapsing MS

Clear progression in disability level from the onset,
but also clear acute relapses that may or may not include memory.
  • diagnosed with RRMS at onset 85% 85%
  • RRMS patients who develop SPMS within 10 years 50% 50%
  • diagnosed with PPMS 10% 10%
  • diagnosed with PRMS 5% 5%

Causes of MS

The cause(s) of MS are currently undetermined, but researchers are studying several possibilities.

Immunologic Reaction

MS is generally believed to be an autoimmune disease. This means that the immune system, which normally protects us from disease and infection, reacts against normally occurring antigens (proteins that stimulate an immune response) as if they were foreign. In other words, the body mistakenly attacks itself.

While some component of myelin is believed to be the target of that attack, the exact antigen remains unknown.

Viral / Infectious Agents

Some data suggest that a common virus or other infectious agent may play a role in the cause of MS. Whether it is a persistent viral infection or an immune reaction caused by a temporary viral infection in the central nervous system or elsewhere in the body is not yet known.

Environmental studies suggest that some factor – probably infectious – must be encountered before the age of 15 in order for MS to develop later in life.

Environmental Factors

Scientists who study disease patterns have learned that MS occurs more frequently in geographic locations that are farther from the equator.

Some researchers believe vitamin D, which the body produces naturally when the skin is exposed to sunlight, may be involved. People who live closer to the equator are continually exposed to greater amounts of sunlight. As a result, they tend to have higher levels of naturally produced vitamin D, which is thought to have a beneficial impact on immune function and may help protect against autoimmune disease, like MS.

Genetic Factors

While MS is not believed to be a hereditary disease, having a family history of MS (particularly in a parent or a sibling) does make a person more likely to develop it. In a family in which one parent has MS, the risk that their children will develop the condition is estimated to be between 2 and 5 percent.

Nevertheless, the genetic picture of MS remains largely unknown and is proving harder to understand than other autoimmune diseases. While some autoimmune diseases are causes by one or two malfunctioning genes, MS appears to involve defects in many genes, each with only a modest effect.

Over the years, aspartame (an artificial sweetener), allergies, physical trauma, exposure to heavy metals, and environmental toxins have also been studied as potential causes of MS. Little or no evidence has been found to substantiate these claims.

Who Gets MS?

Diagnosed WorldWide

U.S. Diagnosed Patients

Diagnosed Per Week

Age when Diagnosed

Statistics indicate that there are currently 350,000 to 500,000 people in the U.S. who have been diagnosed with MS. Two hundred people are diagnosed with MS every week and more than 2.5 million people are living with the disease worldwide. However, because the Centers for Disease Control and Prevention does not require U.S. physicians to report new cases of MS and the symptoms of the disease can go unrecognized for some time, these numbers are only estimates.

MS is more common in women, appears more frequently in Caucasians than in Hispanics or African Americans, and is relatively rare among Asians and certain other ethnic groups. MS is most commonly diagnosed in individuals between the ages of 20 and 50, although it can develop in young children and teens as well as older adults.

Data and statistics on this page courtesy of the MS Foundation ( and from HealthLine (