Do we know the cause of MS?

MS was first recognised over 130 years ago. In spite of this, we still do not fully understand the cause of MS. There has been a great deal of research on what actually triggers MS and a number of theories have been proposed over the years.

The theory that is widely held now is that MS is an autoimmune disease. This is where the body's immune system, which should in theory only attack invading germs, turns on the body's own tissues.

Other autoimmune conditions include rheumatoid arthritis, where the lining of joints become inflamed, Crohn's Disease which affects the wall of the intestines and type I diabetes where the immune system destroys the cells in the pancreas that make insulin.

In the case of MS, the immune system attacks the nerve coverings in the central nervous system, known as myelin. The reason for this reaction is unknown but it is thought that the genetic make up of some people makes them more susceptible to triggering the immune damage and that environmental factors, including infections, may act as triggers. At present several different viruses have been linked with MS, but there is no evidence that a specific virus causes the disease.

The physical damage caused by MS only happens in the central nervous system, which includes the brain, optic nerves and spinal cord. However, as these organs control the functions of the whole body, symptoms can affect many different areas.

How MS affects an individual depends on where damage occurs in the central nervous system and which nerve messages are interrupted or blocked. As well as the variety of symptoms, the severity and duration will also vary considerably from person to person.