Pamidronate treatment of severe osteogenesis imperfecta in children under 3 years of age

Severe osteogenesis imperfecta (OI) is a hereditary disorder char-acterized by increased bone fragility and progressive bone deformity. Cyclical pamidronate infusions improve clinical outcome in children older than 3 yr of age with severe OI. Because earlier treatment may have potential to prevent deformities and improve functional prog-nosis in young children, we studied nine severely affected OI patients under 2 yr of age (2.3–20.7 months at entry) for a period of 12 months. Pamidronate was administered iv in cycles of 3 consecutive days. Patients received four to eight cycles during the treatment period, with cumulative doses averaging 12.4 mg/kg. Clinical changes were evaluated regularly during treatment, and radiological changes were assessed after 6–12 months of treatment. The control group consisted of six age-matched, severely affected OI patients, who had not re-ceived pamidronate treatment. During treatment bone mineral den