Before MRI, many people had MS without a diagnosis.
The only way the average Joe remembered that somebody had MS is because they were "in a wheelchair". All others went unnoticed.

My great grandfather suffered from "creeping paralysis" whatever that meant.

However; I do believe it is more likely that our family members may run in packs when it comes to autoimmune diseases...not necessarily MS.

My mom's family was riddled with RA, Hashimotos, etc. Mom had scleroderma.
I have MS and my sister has Sojgrens disease. I think the little glitch is in our DNA, and it just takes some environmental or other factors to give the nasty thing a direction to take.

They say we all have Cancer cells too. Whether or not we develope cancer is subject to the same riddle.

Whatever the case, take it from a friend of mine who nearly went nuts because Huntingtons ran in his family. He drank, took risks, used drugs etc., for fear he would have the Huntington's gene. Well, all his crazy living gave him cancer.....and he died.

I will say this when it comes to your children.....have them get their vitamin D3 level checked. Its about the only possible prevention out there.