Multiple sclerosis is a long-term disease in which the immune system damages myelin, the insulation on nerve fibres in the brain, optic nerves and spinal cord. Step through the numbers, who gets it and where it strikes, then pick a symptom to see where it comes from.
Bars use published figures. The latitude bars are schematic: they show the direction and steepness of the gradient, not values for any place.
Symptoms and where they come from
MS can affect any part of the central nervous system, so what a person notices depends on where the lesions are. Pick a symptom, or hover over one, to light the part it usually comes from. These are typical links, not a way to tell what is causing anyone's symptoms.
Exam hookMS is a disease of the central nervous system. CNS myelin is made by oligodendrocytes, peripheral myelin by Schwann cells, and the peripheral nerves are not the MS target. 246 Typical patient: a young adult woman; mean age at diagnosis 32, female to male about 2–3 : 1. 488,489
In plain wordsMS is when the body's defence system damages the insulation on the nerve wires of the brain, eyes and spinal cord. Messages along those wires slow down or stop, and what a person feels depends on which wires are hit. It is not contagious.