MS is thought to be from a combination of an environmental trigger and genetic susceptibility. The environmental trigger is still unknown. The human gnome project that is determining the human gene code has found 3 identical twins -one developed MS and 2 did not. Since they are identical twins they have the same genetic code--- it proves MS is not entirely genetic. (my comment-this proves a genetic fix will not be found)
But since they were born on the same day, exposed to the same things, raised in the same family, raise in the same geographical location --it makes what the environmental trigger even more confusing or elusive?