A patient in her mid-50s complains of foot and leg pain. She's post-menopausal with low bone density. A classic case of post-menopausal osteoporosis.Not exactly. And it won’t start to become clear until it gets to the point of her having repeated metatarsal bone fractures.Let’s go back a little. It’s 2005. Our patient visits her family doctor complaining of pain in her legs and feet. But the discomfort she's experiencing isn't your typical aches and pains associated with aging. “She develops a lot of [foot and leg] pain … So much so that she required pain management for this pain and her gate started to become affected,” shares Dr. Katherine Dahir, a professor of medicine at Vanderbilt University, who specializes in metabolic bone disease.Her gait becomes wobbly and she’s experiencing an acceleration of degenerative changes in her spine. An osteoporosis screening reveals she has low bone density. She’s diagnosed with post-menopausal osteoporosis and is treated with bisphosphonates, the standard of care for patients with osteoporosis. And this is when things get much more complicated. Although all signs show an improvement in bone density, she begins to experience metatarsal bone fractures, which is highly unusual with osteoporosis. And not only does she have these unusual fractures, the fractures will not heal.  “And so that's when you need to put your thinking cap on and try and figure out, why is this patient a treatment failure?” says Dr. Dahir.To solve the case, the patient’s team studies her labs and finds a missing flag. “... It was called alkaline phosphatase, which is seen in a routine chemistry panel. Back at that time, it was only flagged if it was above the normal reference range because that usually indicates liver disease, but it wasn't flagged if it was below the normal reference range because that was considered to be non-significant.” But this finding would prove to be very significant. Combined with new research at the time, it helped identify a diagnosis for this patient — showing the importance of medical research that leads to more treatment options and more hope for patients.