Andrew Wilner, MD: Multiple sclerosis is a neurologic disease that affects the central nervous system, which is the brain and spinal cord.
Andrew Wilner, MD (cont.): We don’t know what causes multiple sclerosis. It appears to be a combination of genetic factors and environmental factors.
Andrew Wilner, MD: For example, people who smoke have twice the risk of developing multiple sclerosis than people who don’t smoke.
Andrew Wilner, MD (cont.): On the other hand, we do know that people who have a relative with multiple sclerosis do tend to have an increased risk of developing multiple sclerosis themselves.
Andrew Wilner, MD: But multiple sclerosis is rarely passed on from mother to child in a typical hereditary way. Even in identical twins that have the same genetic composition, both will not necessarily get multiple sclerosis.
Andrew Wilner, MD (cont.): If one twin develops it, the other one has about one chance in four. So we know that environmental factors are very important, but exactly what these factors are have not yet been defined.