Dermatomyositis and other muscle disease

I was wondering if anyone had any other family members diagnosed with other muscle diseases? I was diagnosed a couple months ago with dermatomyositis (though so far, the 2 rheums I have seen think I just have the skin form), but over this same period of time, my 6 year old was being evaluated for hypotonia when his bloodwork came back abnormal and the doctors believe he has either a congenital or metabolic muscle disease, but won't know for sure which one until his muscle biopsy comes back, hopefully by Christmas. No one so far thinks the two things are related, even though his would be inherited, but I think its very odd that we would both be getting diagnosed with such rare diseases, and that both can have a muscle component. So I guess I was wondering if anyone had experienced anything similar. Scouring the internet, I did find one case study of a mother diagnosed initially with Dermatomyositis, but later on it turned out to really be an expression of her carrier status for muscular dystrophy, which she had two sons who both had it.

Hi Rachel,
I have been told that while DM is not genetic, that other autoimmune diseases can get tagged on and follow a genetic path - so even though a family member may not get a myositis, they may have another autoimmune condition. I feel like there are so many though, that those odds are pretty good for anyone, though!