HPP and what to take for bad dexa density

This is the first place I have ever heard of HPP (an inherited soft bone disease that can be mistaken for osteoporosis?!)
Question to any of you who know about it: If the ALK blood test number has always been in normal range on my blood tests does that mean I definitely DON'T have HPP?
I am wondering because I do have the other physical symptoms of it!
I am finishing up 2 years of Tymlos in september and IF I have HPP it looks from some comments here that the second drug I take should not be a bisphosphonate? yikes