However, they have been reported to cause adverse reactions, such as atypical femoral fractures and jaw osteonecrosis, resulting in reduced reliance on these medications.119 To date, antiresorptive pharmaceuticals approved for osteoporosis comprise five major classes: bisphosphonates, sex hormones, selective estrogen receptor modulators, monoclonal antibodies, and calcitonin.337. This evidence concerns the gene CALCA and osteoporosis.