Science Snippet: Breaking Down MS

As many as 2.5 million people in the world have multiple sclerosis (MS), a debilitating autoimmune disease in which a person’s own immune system eats away at the protective sheath around long extensions of neurons in the brain and spinal cord. These extensions, called axons, can carry impulses at high speed because the sheaths provide insulation. When this insulation is lost, axons begin “short-circuiting,” resulting in symptoms such as numbness or tingling, loss of balance, lack of coordination, and weakness in arms or legs. The disease is progressive and becomes more debilitating over time. Sometimes the disease is of the relapsing type, with periods of relative normality, followed by the return of symptoms, perhaps more severe than before. Now for the encouraging news. Europe’s leading science magazine, Nature, devoted part of a recent issue to the latest research on MS. Three culprits appear to be involved: the presence of the herpes-virus (Epstein-Barr) that causes mononucleosis; low levels of vitamin D; and genetic variants that increase susceptibility. It has long been known that the disease may occur in clusters (“hot spots”) in a given geographic area. Recent studies show that susceptibility to MS decreases the closer one lives to the equator, suggesting that more sunlight exposure to produce vitamin D is protective. Although effective drugs to treat MS are nonexistent, there are nine drugs now undergoing tests that may produce a “magic bullet” kind of therapy. (Nature, Dec. 1, 2016, “Outlook on Multiple Sclerosis”)