My daughter is 3 and has CF. She sometimes complains about pain in her knees or hips, and tired legs. I asked our clinic nurse about it and she says that this is related to the CF and is an arthritic pain that they do not know much about, but some patients do get it.Does anyone have any information on this or useful sites to get information? Is this related to all mutations or just certain ones? Does it worsen with age? Does it have anything to do with her diet?Thanks,AM