Multiple sclerosis (MS) is a condition that can affect the brain and spinal cord, causing a wide range of potential symptoms, including problems with vision, arm or leg movement, sensation or balance.
It's a lifelong condition that can sometimes cause serious disability, although it can occasionally be mild.
In many cases, it's possible to treat symptoms. Average life expectancy is slightly reduced for people with MS.
It's most commonly diagnosed in people in their 20s and 30s, although it can develop at any age. It's about 2 to 3 times more common in women than men.
MS is one of the most common causes of disability in younger adults.