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Multiple Sclerosis Health Center

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What Is Multiple Sclerosis?

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Multiple sclerosis, or MS, is a long-lasting disease that can affect your brain, spinal cord, and the optic nerves in your eyes. It can cause problems with vision, balance, muscle control, and other basic body functions.

The effects are often different for everyone who has the disease. Some people have mild symptoms and don’t need treatment. Others will have trouble getting around and doing daily tasks.

MS happens when your immune system attacks a fatty material called myelin, which wraps around your nerve fibers to protect them. Without this outer shell, your nerves become damaged. Scar tissue may form.

The damage means your brain can’t send signals through your body correctly. Your nerves also don’t work as they should to help you move and feel. As a result, you may have symptoms like:

The first symptoms often start between ages 20 and 40. Most people with MS have attacks, also called relapses, when the condition gets noticeably worse. They’re usually followed by times of recovery when symptoms improve. For other people, the disease continues to get worse over time.

In recent years, scientists have found many new treatments that can often help prevent relapses and slow the disease’s effects.

What Causes MS?

Doctors don’t know for sure what causes MS, but there are many things that seem to make the disease more likely. People with certain genes may have higher chances of getting it. Smoking also may raise the risk.

Some people may get MS after they’ve had a viral infection -- like the Epstein-Barr virus or the human herpesvirus 6 -- that makes their immune system stop working normally. The infection may trigger the disease or cause relapses. Scientists are studying the link between viruses and MS, but they don’t have a clear answer yet.

Some studies suggest that vitamin D, which you can get from sunlight, may strengthen your immune system and protect you from MS. Some people with higher chances of getting the disease who move to sunnier regions seem to lower their risk.

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