Multiple sclerosis usually begins between 20 and 50 years old.
=== Lesions ===The name multiple sclerosis refers to the scars (sclerae  better known as plaques or lesions) that form in the nervous system
== Prognosis ==The availability of treatments that modify the course of multiple sclerosis beginning in the 1990s, known as disease-modifying therapies (DMTs), has improved prognosis

