Fragile without fractures.

Despite being the commonest inherited disease of bone, osteogenesis imperfecta (OI) is a rare cause of fractures in daily clinical practice. Its prevalence in the general population is 1 to 5 per 100 000. The clinical spectrum ranges from mild forms with relatively few fractures and normal mobility to the lethal form, with multiple intrauterine fractures and death in perinatal period. The diagnosis of OI is based on fracture rates, family history, and clinical signs. However, the rarity of the condition coupled with the subtle signs of mild OI can lead to cases being missed altogether or misdiagnosed in some as “post-menopausal” osteoporosis. In asymptomatic members of a family with mild OI, it is even harder to decide whether they have the condition or not. It has recently been suggested that consultation by a physician familiar with the variability of OI (such as a medical geneticist) is essential for the early diagnosis. Clearly, this is possible only in selected centres of expertise, and in most clinical settings one is forced to tackle the problem with locally available resources.