The major cause of multiple sclerosis is environmental: genetics has a minor role - Yes

It is clear that multiple sclerosis (MS) has a complex aetiology that involves both genetic and environmental factors and that both make a significant contribution to causation. However, the weight of evidence would favour a significantly greater role for the environment over genetics. There is now ample evidence for a profound effect of the environment on MS causality, with at least four and probably more factors directly contributing, with the reported effect sizes significantly greater than any identified genetic factor.

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