Welcome to the site, although I’m sorry to hear that you are suffering, and that your family is so greatly affected. I think I could write a book in response to your questions, but I did want to hit on a couple of things. I do NOT believe we need to have EDS (or joint hypermobility to have POTS — we had a patient in the office just last week with NO hypermobility, but a clear case of POTS). As you’ll read, many of us have problems with histamine-producing cells, including mast cells, but I do not believe that mast cells are the only (and perhaps not even the primary) cell causing problems. I’m so glad that you have the book, because we spend a lot of time explaining the role of undiagnosed intracranial pressure problems (of which you seem to have symptoms). Evaluating/treating this may offer you some immediate relief. Let us know? 😉