Multiple Sclerosis - What Is the Cause?

The cause of MS is unknown. It may be the result of a combination of environmental and genetic reasons. Common viruses may cause attacks or recurrences. There is strong evidence that MS is “immune-mediated.” This means your own immune system attacks the central nervous system (an auto-immune disease).

MS begins with an inflammation in your central nervous system (the brain and spinal cord). This is followed by the loss of the protective myelin sheaths that are wrapped around nerve fibers. Myelin is like the insulation that covers and protects electrical wires. When the myelin is damaged, nerve impulses are slowed, garbled, or blocked. The inflammation causes lesions (called “plaques”) to develop in your brain and spinal cord. Symptoms then begin to appear. They can range from numbness in the arms and legs to paralysis or vision problems.

You have a slightly higher chance of getting MS if you have a close relative with the disorder. But it is not truly inherited in the general population. Researchers think there is a 1 or 2 per 1000 chance of getting MS. However, in families where MS already exists, the risk of another family member getting the condition is about 6 in 1000. This seems like a higher risk, but it is not thought to be a major reason for getting MS.