A woman with sensory deficits, paresthesias, and ataxiaCasto, Jon MS, PA-C; Childers, Jennifer MS, PA-CJournal of the American Academy of Physician Assistants: March 2014 - Volume 27 - Issue 3 - p 34–38 doi: 10.1097/01.JAA.0000443966.23610.0f Case Report Abstract Author Information ABSTRACT: Multiple sclerosis (MS) is a demyelinating and inflammatory disease that is thought to be autoimmune in nature. MS typically affects young women ages 20 to 40 years, but late-onset MS (after age 50 years) is more prevalent than previously thought. Between 4% and 9% of patients with MS have symptoms onset after age 50 years. Jon Casto practices at Family Health Associates in South Charleston, W.Va. Jennifer Childers is an associate professor in the PA program at Marietta College in Marietta, Ohio, and practices part-time in occupational medicine. The authors have disclosed no potential conflicts of interest, financial or otherwise. © 2014 American Academy of Physician Assistants.