Bisphosphonate-Induced Osteopetrosis

Bisphosphonates are increasingly used in conditions such as osteogenesis imperfecta and juvenile osteoporosis. Their potential adverse effects in growing children have been a concern, however, since bisphosphonates inhibit skeletal resorption by suppressing the activity and function of osteoclasts. The authors describe a case of drug-induced osteopetrosis in a 12-year-old boy who had received high doses of pamidronate for nearly three years. Bisphosphonates, synthetic analogues of inorganic pyrophosphate, potently inhibit skeletal resorption by suppressing the recruitment and activity of osteoclasts and shortening their life span. 1 Consequently, several bisphosphonates were developed to treat hypercalcemia (associated with cancer), osteoporosis, and Paget's disease of bone and are used for additional disorders in adults. 1 Increasingly, bisphosphonates are being administered to children 2 – 4 and have been reported to improve clinical outcomes and augment bone mass in conditions such as osteogenesis imperfecta, 5 juvenile osteoporosis, 2 and fibrous dysplasia, 6 although controlled studies of these compounds in children are lacking. 3 , 4 , 7 Genetic defects that abrogate the action of osteoclasts cause . . .