- :patients with history of increased bone fragility by BMD criteria (T score > -1). In addition, the subjects will be enrolled only if they have clear evidence of low bone turnover as indicated by low normal levels of biochemical markers of bone turnover and finding of low bone turnover on bone biopsy. Each subject and his/her treating physician will have agreed that the rhPTH is the best treatment for the patient. Treatment with rhPTH will be considered only if the bone histomorphometry reveals a low turnover state and excludes other known forms of bone disease such as osteomalacia.