Hi Jeanie, You can say almost without contradiction that TAM affects the skeletal muscles i.e. those that attach to the bones and move the limbs, jaws etc. So you don't expect it to affect the heart or respiratory muscles, but there are very rare exceptions. I have never seen a credible case report of the heart being affected, but there is one relating to the respiratory muscles.
This is the it: "http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2080694/":http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2080694/
The full article is there for free. It's a very odd case, because only the respiratory muscles were affected. Usually the most strenuously used muscles are affected first, such as the legs or the arms.
You are right, there is no known cure for adults, but never accept that there is no treatment. If any medico says that, write them off and find a better one. Easier said than done, I know. If the limbs are affected, a good physical therapist can help. And I mean a good one, not your local village sports injuries therapist. I don't know about the US, but in Oz and the UK there are neuro-physiotherapists that are excellent, not that TAM is neurological.
Have we talked about treatment with calcium antagonists such as verapamil? There is good scientific research supporting this and some TAM folk have near miraculous benefits.
Sorry, I cannot answer your last question.
All the best,
George