[Pathologic anatomy of osteogenesis imperfecta. Light and electron microscopic studies of supportive tissue and skin].

Osteogenesis imperfecta (OI) is characterised by an abnormal fragility of the bones, and more or less marked blue sclerae. The mode of inheritance is both autosomal dominant and recessive. Facultatively, dentinogenesis imperfecta, abnormal laxness of joint ligaments, and, in early adulthood, deafness, may also be associated. In numerous cases, dwarfism, which may be very marked, and kyphoscoliosis of varying degrees, may also be found. The presumed cause of OI is a disturbance of collagen metabolism, which is associated with an insufficiency state of the osteoblasts; this leads to inadequate formation of osteoid and bone. The first detailed descriptions of the clinical picture were published by Ekman (1788) and Vrolik (1894). In the meantime, the original classification into OI congenital and OI tarda--with its better prognosis--has proved inadequate. In accordance with its genetic heterogeneity, the variations in the clinical symptomatology and its varying prognosis, the condition is, today, divided into four types in accordance with a proposal made by Sillence et al. (1979). The treatment of the genetically determined connective and supporting tissue disease, OI, presents something of a problem. Among the attempts at conservative therapy, treatment with the flavonoid, (+)-catechine, has so far provided the best results. Surgically, pronounced bowing of the tubular bones should be treated by the use of telescopic nails, with the aim of correcting and stabilising them. The diagnosis of OI, as also the differential diagnosis vis-a-vis other osteopenias, has to date been established almost exclusively on the basis of clinical and radiological findings. Differential-diagnostically, juvenile idiopathic osteoporosis, numerous to date unclassifiable osteopenias, and the lethal type II OI, must be distinguished. The aim of this investigation was to establish the diagnosis and differential diagnosis of OI on the basis of light- and electron-microscopic examinations of the supporting tissues. Further, an attempt was made to relate corresponding pathomorphological findings to the clinically different types of OI, and, in forms of OI with a particular course, with so-called hyperplastic callus formation or an increased tendency to develop pseudoarthrosis, to find morphological equivalents. In addition, tissue changes were investigated prior to and during treatment with catechine. Additional investigations of skin biopsies were performed with the aim of correlating morphological findings with the biochemical changes of collagen metabolism.(ABSTRACT TRUNCATED AT 400 WORDS)