I increasingly see the term 'hemochromatosis' used to describe damaging iron overload even when caused by factors other than the specific 'HFE' gene, such as other diseases (hereditary or not).
I also see a growing trickle of advice -- often from the kinds of cranks who sometimes turn out to be right -- pointing at iron exposure/accumulation, below levels that would result in a formal diagnosis of overload, as contributing to other chronic diseases and symptoms of aging. (Perhaps, the evolved mechanisms for iron regulation are optimized for 40-year lifespans, and not 80+-year lifespans.)
My layman's hunch is that the consensus view on iron will shift in coming decades. We'll see.
B) The iron system has evolved with multiple mechanisms for storing excess iron and inhibiting uptake of excess iron.
C) Several forms of iron build-up are well documented, and none of them appear to have symptoms like MS.
Here's a good article on disorders of iron metabolism: http://content.nejm.org/cgi/content/extract/341/26/1986