people in the U.S. are living with multiple sclerosis.
Most people with MS are diagnosed between the ages of 20 and 50, with at least 2-3 times more women than men being diagnosed with the disease.
new cases of MS are diagnosed each week in the United States.
What is multiple sclerosis?
Multiple sclerosis (MS) is an autoimmune condition. Autoimmune conditions occur when the body’s immune system mistakes its own tissues for foreign invaders, such as bacteria or viruses. The confused immune system springs into action, seeking out to destroy the “invaders” in the tissues.
In the case of multiple sclerosis, the immune system attacks the fatty substance that protects your nerve fibers in the brain and spinal cord. This attack results in nerve damage, which can slow signals that travel along the nerve fiber and cause problems with vision, balance, muscle control, and more. 
Who is affected?
Anyone can be diagnosed with multiple sclerosis, but it is more common in women than men.  Women are also more likely than men to have a relapsing form of multiple sclerosis, which means your symptoms flare up and then stabilize in episodes.  The condition is generally diagnosed between the ages of 20 and 50. 
Doctors aren’t sure about what causes multiple sclerosis, but believe that a combination of genetics and environment are responsible.  Other factors like climate, smoker status, and other medical conditions may influence your level of risk as well.
What happens in your body?
Common symptoms of multiple sclerosis include:  
- Numbness, weakness, or tingling in one or more limbs, typically on one side of your body at a time
- Lack of coordination and difficulty walking
- Vision problems such as blurred vision, partial or complete vision loss, pain during eye movement, or prolonged double vision
- Slurred speech
- Problems with sexual, bowel, or bladder function
Not everybody has the same symptoms, and not all individuals with multiple sclerosis have the same severity of the condition. Experiences of the condition also depend on which nerve fibers in the body are most affected in each individual.
Some people have what is called primary-progressive multiple sclerosis, which is when symptoms gradually and steadily arise. But most people have relapsing-remitting multiple sclerosis, which is when symptoms develop over a few days or weeks and then disappear for months or years.  Up to 70 percent of people with relapsing-remitting MS eventually develop secondary-progressive MS, which involves a steady progression of symptoms, sometimes with and sometimes without periods when these symptoms disappear (also called remission). 
How do I know if I have MS?
It is important to get an accurate diagnosis as quickly as possible to make sure that the condition does not worsen. The best way to do this is by visiting your doctor and, if possible, getting a referral to visit a neurologist, a doctor with specialized training in treating multiple sclerosis.
No one test can diagnose multiple sclerosis, but some ways that your doctor can assess whether you have the condition is through assessing your medical history, and conducting a physician examination, blood tests, spinal tap, MRI, and evoked potential tests.