Multiple sclerosis (MS) is an immune-mediated, inflammatory, neurodegenerative condition of the central nervous system, affecting both the brain and spinal cord. It affects approximately 100,000 people in the UK and is three times more common in women than men. People are most likely to be diagnosed with MS in their 20s to 40s, but many notice their first symptoms years before they are diagnosed. MS is one of the leading causes of disability in young adults.

Nerves in the central nervous system are covered in a protective layer of fatty protein called the myelin sheath, which coats, protects and insulates the nerve fibres enabling them to quickly conduct impulses between the brain and different parts of the body. In MS, the immune system mistakes the myelin for a foreign substance and attacks it, damaging the protective sheath. This process, known as demyelination, disrupts the messages being transmitted along the nerve fibres, slowing them down, or even stopping these messages getting through completely. The term ‘sclerosis’ means scarring due to the scars or lesions caused by demyelination within the central nervous system.

The exact reason why someone develops MS is unknown, however a combination of genetics and environmental factors appear to be contributory.