Fibrogenesis imperfecta ossium.

The case history, clinical course and laboratory findings in a 66-year-old woman with fibrogenesis imperfecta ossium are reported, the sixth case in the literature. The condition is characterized clinically by intractable skeletal pain and progressive immobility. Though serum alkaline phosphatase has been raised in all patients, there are no specific haematological or biochemical findings. The radiological features of coarse and dense trabecular pattern with symmetrical and diffuse involvement of all bones without expansion or change of shape, together with periosteal reactions and soft tissue calcification are characteristic. The macroscopic appearance of bone shows large areas of opaque white and brittle trabeculae. The histological findings mimic those of osteomalacia unless examined under polarized light which shows the loss of normal birefringence. On electron microscopy the normal lamellar pattern made up of orientated collagen fibrils all about 80 nm diameter is replaced by a random tangled pattern of much thinner irregularly curved fibrils, some as thin as 5nm. The condition appears to be acquired, leading to erosion of the normal skeleton and replacement with an abnormal fibre deficient matrix. There is no definitive therapy at present.