I'm idiopathic but I believe mine is hereditary based on my knowledge of my Dad and the things I observed in him over the years as he never gave it a second thought. I asked my Neuro yesterday what benefit there would be to my going through expensive genetic tests to find out what it is, if that would even reveal it, and the end result might be just being able to put a name to it. I also asked if there could be anything to do to stop it, and he indicated "no", so I'm thinking that any further investigation at this point would be expensive and wouldn't really help me in any way, so I'm now leaning toward just accepting that I have it and not pursuing it further. This is just my opinion concerning my own situation so please don't think I'm trying to tell others that they should do the same, as I'm not. Putting a name to this, if that can even be done, won't stop it or change its course or the treatment I receive. My thoughts may change as it progresses more, but for now this is where I'm at.