​What is multiple sclerosis?

​Multiple sclerosis (MS) is an immune-mediated disease affecting the brain and spinal cord, collectively known as the central nervous system (CNS).

In people with MS, the communication of nerve impulses along nerve cells within the CNS is disrupted. This occurs when the protective layer (also called myelin) surrounding the nerve cells that normally speeds up transmission of nerve impulses, is attacked by the immune system.

Repeated immune attacks can prevent the proper repair of myelin, and in some cases, cause damage to the nerve cells themselves, resulting in permanent injury to the brain and spinal cord.