I have Hashimoto's and my mother was Hypothyroid. I don't know if she ever had an antibody test but I'm sure that's what she had. My sister is Hypo with Hashi's as well and has some degree of arthritis.

No one in my family has ever had MS that we know of and I discussed this with my endocrinologist on my last visit. I may be slightly paraphrasing here but basically he said "What you inherited was a tendency for your body to make antibodies against itself".