Osteoporosis (OP) is a complex disorder likely involving the effects of multiple low-impact, common changes in the human genome that alter bone remodeling and/or mineralization.(7-9) The investigators propose that high-impact, rare, genetic variants predispose some OP patients to AFFs. Treatment with BPs could engender OP AFFs. The investigators' hypothesis: High-impact rare variants (i.e., mutations) that occur in genes/proteins that regulate pyrophosphate/phosphate homeostasis or BP metabolism predispose to OP AFFs and are unmasked in OP patients given BPs. Identification of these variants will guide OP therapies, perhaps on an individual basis (i.e., "personalized medicine"),(9) and reduce the incidence of OP AFFs.