A condition called clinically isolated syndrome (CIS) is considered the first clinical presentation of disease. People with CIS may never experience another episode of symptoms, or they could progress to full MS. Most people with MS (about 85%) are diagnosed with relapsing-remitting MS, which is characterized by disease relapses and periods of remission. About 10–15% of patients are diagnosed with primary progressive MS at disease onset — an MS type in which symptoms steadily worsen over time.
MS is not considered a hereditary disease; however, about 1 in 8 patients have a family history of MS, suggesting a genetic component that may contribute to the development of the disease. It is estimated that about 200 genes may, to some extent, play a role in MS development.
MS is characterized by the body’s immune system attack to the central nervous system — the brain, spinal cord, and optic nerves. Symptoms vary depending on which specific parts are most affected. Problems with vision and movement, as well as numbness or tingling sensations, are often reported by patients.
MS is a chronic, lifelong disease, and symptoms generally get worse over time, potentially causing physical disability, cognitive difficulties, and emotional challenges. Walking can become difficult, and many patients eventually need an assistive device such as a cane, walker, or wheelchair. MS can decrease a person’s quality of life by interfering with one’s ability to work and to carry on usual life activities.
MS itself is rarely fatal but, depending on the severity of the disease, it may increase the risk of life-limiting complications including severe infections and swallowing difficulties.