MS, Multiple Sclerosis usually affects those who live in the colder northern countries. I was born in the border town of Fort Covington, just a walk down the street to Canada. And then I grew up in another nearby border town. In the winters our temperature dropped below freezing and stayed there until March. My mom was Irish and my dad French Canadian. My brother was just like me.
MS usually starts somewhere between 20-50 years. Just like RA there is an elderly onset MS striking those age 60 and above. Children also develop MS.
MS is an autoimmune disease where the T cells of our immune system think the cells of the myelin sheath, the nerve covering, is foreign and must be attacked. This arbitrary attack affects the brain, spinal cord and the optic nerve and creates a a variety of symptoms. More women than men have MS. Genetics play a role.
MS interrupts the flow of information within the brain and between the brain and the body. Walking becomes difficult. Hands may lose their grip. Skin may itch. There may be bladder issues. Vision may become blurry. There is a wide range of symptoms depending what areas of the nervous system are affected.
While there is no cure for MS, there are medications and treatments that relieve symptoms.
The National Multiple Sclerosis Society has an excellent web site with helpful information.