Multiple sclerosis is a condition that affects the brain and spinal cord.
It's a lifelong condition that can sometimes cause serious disability, although it can occasionally be mild. It happens when the immune system attacks the protective sheath - myelin - that covers nerve fibres and disrupts the communication between your brain and the rest of your body.
Affected nerve fibres can become vulnerable to damage, and over time may be lost entirely. When this happens, messages can no longer get through and symptoms become permanent. MS is most commonly diagnosed in people in their 20s, 30s and 40s although it can develop at any age, according to the NHS.
