Studies of type I collagen in osteogenesis imperfecta

Osteogenesis imperfecta: perspectives and opportunities

The last 2 years have seen additions proposed to the very limited armamentarium of treatments for osteogenesis imperfecta. These include the use of bisphosphonates to decrease bone resorption, growth hormone to augment growth and collagen production, and bone marrow transplantation to create chimeras at the level of the collagen production unit in bone. Although there are optimistic proponents for each strategy, the lack of well-controlled studies and the absence of clearly defined objectives for therapy hinder clear assessment.

Chronic ventilator use in osteogenesis imperfecta congenita with basilar impression: a case report

Osteogenesis imperfecta, a rare connective tissue disorder, is known to be associated sometimes with the invagination of the basilar skull. This deformity may disturb respiratory function secondary to brain stem compression and hydrocephalus. In addition, the deformed thoracic cage and fragile ribs make pulmonary care more complicated. A case of 24-year-old man is presented with brain stem compression syndrome secondary to osteogenesis imperfecta congenita with basilar impression. He developed respiratory failure and became tracheostomy positive-pressure ventilator dependent at the age of 21 years. He also suffered multiple skeletal abnormalities and mental retardation, and following the brain stem compression, severe quadriparesis. The patient's condition is stable since he has been using the ventilator and he is currently living in the community.

Bone strength in infants

The results from a study of bone strength in normal infants is presented. The fibular bones of infants dying from SIDS were tested mechanically by a three-point bending test and the behaviour of the bony structure determined by measuring several variables. Correlations between these variables and infant age, length, weight and length of fibular bones were found and base-line values for bone strength established.

The perinatal autopsy: a contemporary approach

As autopsy rates in general hospitals decline, interest in the perinatal autopsy continues to rise, reflecting the emergence of a vigorous specialty growing in parallel with fetal medicine, prenatal diagnosis and clinical genetics. Perinatal autopsies are best carried out in tertiary centres which provide these services. Meticulous documentation, flexibility of technique, intelligent use of laboratory tests and wide systematic histopathologic sampling are emphasized. Microbiologic examination is of particular value when carried out by a laboratory having a special interest in genital tract and perinatal pathogens. Karyotyping must be selective if resources are to be conserved and is most productive when there are multiple malformations. Perinatal autopsy is not complete without examination of the placenta and significant lesions should be clearly distinguished from curiosities and from changes secondary to fetal death. The pathologist's wider contribution to perinatal medicine includes providing high quality data to epidemiology units and auditing committees, contributing to the multidisciplinary management of prenatally diagnosed fetal abnormalities, monitoring iatrogenic disease patterns and supporting the process of perinatal grief management. Special problems and diagnostic challenges are to be found when investigating sudden, unexplained intrauterine fetal death, hydrops, bone dysplasias and complicated multiple pregnancies.

Collagen, genes and the skeletal dysplasias on the edge of a new era: a review and update

This article reviews the newly described biochemical (type I and II collagen) abnormalities and specific gene defects in the skeletal dysplasias. The model of the collagen molecule is described and how collagen is processed from procollagen, where and how abnormalities occur, and the types of abnormalities produced (quantitative and qualitative). The only known type I collagen defects producing skeletal dysplasias--osteogenesis imperfecta, as well as the 'family' of established type II collagen disorders--achondrogenesis type II, hypochondrogenesis and spondyloepiphyseal dysplasia congenita are discussed. Finally, using case presentations, the practical approach to these disorders is shown. The importance of these investigations and the subsequent reevaluation of the clinical and radiological findings of specifically delineated skeletal dysplasias are discussed.

Prenatal counselling and diagnosis in progressively deforming osteogenesis imperfecta: a case of autosomal dominant transmission

A 21-year-old woman with progressively deforming or type III osteogenesis imperfecta (OI) presented for prenatal counselling and diagnosis at 10 weeks' gestation. Family history was non-contributory. At 14.8 weeks' gestation, ultrasonographic examination revealed fetal skeletal hypomineralization, easily compressible fetal cranium, and thickened long bones, indicating that the fetus was also affected. Confirmation of the prenatal diagnosis of OI type III was made following a Caesarean section birth of a male infant with multiple skeletal deformities and blue sclerae implying, in this case, autosomal dominant inheritance.