Hello :] I have a friend, which as far as I know has some sort of muscle disability, where he cannot walk up the stairs (and kind of has a hard time walking down the stairs), he walks slower than others, and if he falls down needs help from others to get up (therefore he is given permission to use the elevator at school). I think it is genetic because all of his brothers and sisters have it too. I am asking this because I am quite curious, and I don't want to ask him because it's obviously an awkward subject. I tried searching for information online and found nothing. So please, I know this site is busy with questions, but I would appreciate an informative reply on the disability or at least reference to another article with the information. Thank you :]