MS is a chronic, disabling disease of the central nervous system. It causes injury to the sheath called myelin that covers nerve fibers in the brain, spinal cord, and optic nerves.

MS is usually diagnosed in adults between the ages of 20 and 50 years old, but it can be found in children.

Nerve Fiber (Neuron)
Myelin Sheath Damage
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A malfunction of the body's immune system seems to be the cause of MS. The immune system attacks and damages the myelin. The exact cause of this malfunction is unknown.