Amyotrophic lateral sclerosis is an affliction.
In addition to secondary progressive MS (SPMS), a small proportion of people with MS (10-15%) experience progressive decline from the onset, known as primary progressive MS (PPMS)
=== Variants ===Atypical variants of MS have been described; these include tumefactive multiple sclerosis, Balo concentric sclerosis, Schilder's diffuse sclerosis, and Marburg multiple sclerosis

