Bisphosphonate therapy for severe osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a heterogeneous group of disorders principally affecting type I collagen. Children with the severe forms of the condition suffer recurrent fractures resulting in limb and spine deformities, and restricted ambulation. Recently, cyclical intravenous administration of pamidronate has proven of benefit to children with the severe forms of OI. Bone mineral density increased, and the incidence of fractures decreased. The treatment does not alter fracture healing, growth rate, or growth plate appearances. Dependence on mobility aids is reduced and there is substantial relief of chronic pain and fatigue. No significant adverse side effects have been noted. New bisphosphonates are under investigation to compare their effects to those of pamidronate. Although the use of bisphosphonates does not address the basic abnormalities that underlie the OI syndromes, it represents the first therapy to significantly alter the natural course of the disease and improve patients' clinical status and quality of life.