Multiple sclerosis (MS) is a progressive disease affecting the central nervous system. It also is known as disseminated sclerosis or encephalomyelitis. The disease is characterized by breakdown of the sheath surrounding the nerve fibers in the brain, spinal cord, and optic nerves. This destruction impairs the transmission of nerve impulses—specifically, the ones associated with vision, sensation, and movement—leading to numbness, tingling, muscle weakness, unsteady gait, mobility issues, and vision problems. The disease may progress steadily or may involve periods of extreme symptom exacerbation as well as symptom remission. At first, the symptoms may appear and subside for several months or years. In progressive forms of MS, remission periods typically become shorter as the disease becomes more advanced. As time goes on, the affected person may suffer from more symptoms, including reflex abnormalities, coordination issues, abnormal bladder function, memory loss, emotional and neuropsychological problems, and in severe cases, complete paralysis. The exact cause of MS is still unknown; however, studies have shown evidence of a genetic factor. Almost five dozen genetic variations have been identified as possible precursors for the disease. When certain environmental factors are present—such as vitamin D deficiency—they may, in conjunction with the genetic variations, further increase a person’s risk of developing MS. While there is no cure for MS, symptoms can be alleviated through administration of certain medications, including corticosteroids. There are also some drugs that may slow the disease’s progress. Stem cell therapy has also been explored as a possible treatment. Physical therapy may also help stimulate and preserve proper muscle function in people with MS.