少年期に診断された骨形成不全症の1例

Osteogenesis Imperfecta Diagnosed during Adolosense : Case Report

　抄録：大腿骨骨幹部骨折，胸腰椎多発圧迫骨折を契機に診断された骨形成不全症（Ⅰ型）に対して，骨生検・骨形態計測を行った．骨形成，骨吸収ともに亢進し，高回転型の骨代謝の像を呈しており，両者の不均衡により骨量は減少していた．Glorieuxらの方法に準じて1年間に計3回pamidronateの投与を行ったところ，初回投与時のみ発熱，軽度の低カルシウム血症の出現をみたが，腰背部痛の消失，腰椎・大腿骨の骨量の増加，脊椎椎体高の回復をみた．少年期に増加した骨折例の場合，骨形成不全症も考慮に入れる必要がある．

　A 13-year-old boy with blue sclera, odontogenesis imperfecta and no family medical history was first confirmed to have osteogenesis imperfecta typeⅠwhen he broke his left femur and multiple vertebral bodies. Iliac bone biopsy specimens revealed simultaneos increase bone formation and absorption. Histomorphometrical analyses also indicated an elevation in bone formation and resorption and a low bone mineral density (BMD). The cyclic administration of pamidronate was started with a 4-month treatment interval. One year later, an 89％ elevation in the BMD of the lumbar spine and a 42％ elevation in the BMD of the femoral neck were observed and height of the compression fractured vertebral bodies had increased. Osteogenesis imperfecta should be recognized as an important differential diagnosis in patients with frequent fractures occurring during adolescence.