Osteogenesis imperfecta. A study of 10 cases

From a retrospective study of 10 cases of osteogenesis imperfecta the authors have verified the usefulness of the classification proposed by Sillence. This has particular advantages in relation to correct prenatal diagnosis and genetic counselling.

Vertebral bone mineral content in osteogenesis imperfecta

Quantitative computed tomography of the lumbar spine was carried out in 28 patients with osteogenesis imperfecta (OI) in order to measure vertebral trabecular bone mineral concentration (BMC). The patients ranged in age from 6-73 years, and included 3 of the 4 major clinical subtypes of the disease. The findings underscore the heterogeneity of osteogenesis imperfecta even among family members with the same disease type. In addition, cross-sectional analysis of Type I OI patients suggests that BMC during young adulthood averages about 70% of normal, and subsequently falls more rapidly than in normal patients. BMC tends to be lower in the more severe forms of OI. Decreased BMC was not found in a few otherwise normal relatives with scoliosis or joint laxity.

Anthropometry and numerical taxonomy in clinical genetics: an example of applied biological anthropology

Biological anthropologists can contribute a unique perspective as well as technical expertise to the diagnosis and classification of genetic disorders. Anthropometry has been used with increasing frequency to characterize syndromes and to establish ranges of variation within syndromes. The specific anthropometric-radiologic technique of metacarpophalangeal pattern profile analysis has proven useful in discriminating individuals with the Prader-Labhart-Willi (PLW) syndrome from unaffected persons. Analysis of these data also indicate a negative correlation between age and Z-score transformations of individual hand bone lengths. These findings sound a cautionary note to clinical investigators who would use the Z-score transformation to standardize for age and sex. Problems encountered in the classification of genetic syndromes afford many parallels with those faced by anthropologists in the classification of living and fossil populations. The reliance on "key" traits and the necessity of focusing on pedigree analysis results in a deemphasis of the total range of variation and typological thinking. Application of numerical taxonomic techniques to the classification of the heterogeneous connective tissue disease osteogenesis imperfecta (OI) illustrates the heuristic value of this technique and points out the need to consider phenotypic overlap when defining typologies. Clinical genetics affords just one example of an area in medicine where the unique training and generalist perspective of the biological anthropologist is in demand. The decline in the availability of positions in the traditional academic habitat for biological anthropologists makes it imperative that graduate students be aware of alternatives and that they obtain training in the practical skills which such alternatives will demand.

Osteogenesis imperfecta type II delineation of the phenotype with reference to genetic heterogeneity

A group of fetuses with a perinatally lethal variety of osteogenesis imperfecta (O.I. type II) is characterized by short limbs, and clinical and roentgenological evidence of severe osseous fragility and defective ossification. Forty-eight cases were reviewed and can be subdivided into 3 groups on the basis of small but probably significant differences in clinical and radiographic findings. Group A (38 cases): short, broad, "crumpled" long bones, angulation of tibiae and continuously beaded ribs. Group B (6 cases): short, broad, crumpled femora, angulation of tibiae but normal ribs or ribs with incomplete beading. Group C (4 cases): long, thin, inadequately modelled, rectangular long bones with multiple fractures and thin beaded ribs. Consistency of findings within sibships suggests the groups reflect genetic heterogeneity. An increased frequency of parental consanguinity, sib occurrence with normal parents, and normal mean paternal age at birth, suggest that most cases of O.I. type II represent autosomal recessive traits. Some previously reported cases and the biochemical findings in one case suggest still further genetic heterogeneity.

Oral findings in osteogenesis imperfecta

The dentitions of twenty-eight patients, each of whom had either an autosomal dominant or a sporadic osteogenesis imperfecta (OI) syndrome, were evaluated. The diagnosis of dentinogenesis imperfecta (DI) could be established in all seven patients with dominantly inherited OI in three families, while all eight persons with dominant OI in three other families had normal teeth. Of the thirteen remaining patients with OI, twelve had no family history of the disorder; four had DI and eight had normal teeth. One person had a family history of OI and DI. All patients with abnormal tooth wear and spontaneous tooth fractures had DI. The DMF ratio increased with age in all patients with OI type I and was higher among the patients with OI type III and DI. Class III malocclusions were found in 66% of the patients. A statistically significant high incidence of impacted first and second molars was noted.

Lethal perinatal type II osteogenesis imperfecta in a family with a dominantly inherited type I

The genetic heterogeneity and the difficulty of accurate genetic counseling in some cases of osteogenesis imperfecta (OI) is shown by the present report. All signs characteristic of OI type II were observed in a newborn infant who died immediately after delivery: curved and deformed limbs, multiple bone fractures, enlarged and soft skull. An autosomal recessive mode is usually admitted for OI type II. However, several cases of OI tarda levis (autosomal dominant) are noticed in the maternal family. The possibility of a relationship between these two types of osteogenesis imperfecta in the same family, which might be important for genetic counselling, is discussed.

Skeletal complications in osteogenesis imperfecta. A review of 153 South African patients

Osteogenesis imperfecta (OI) is one of the most important inherited skeletal dysplasias. Clinical, radiographic and genetic investigations have been undertaken in a series of 153 South African patients from 84 separate families. A further 60 relatives in whom a definite diagnosis could be made were not available for examination. Seventy-nine patients from 39 families had type I OI (mild skeletal fragility, blue sclerae, autosomal dominant inheritance). The orthopaedic complications were mild and stature was relatively normal. Only 26 patients had experienced more than 10 fractures. Trunk shortening, often with mild kyphoscoliosis, was present in 11 patients. One girl was paraplegic, but none of the other patients had evidence of spinal cord compression. Persistent backache was troublesome in 4 cases. Two of the patients were chair-bound and 9 used crutches or wore calipers. Sixteen patients (sporadic cases) had type II OI (lethal in the perinatal period, autosomal recessive inheritance). The orthopaedic importance of this form of OI lies in its differentiation from other types for the purposes of prognostication and planning of long-term management. Twenty-one patients from 14 families had type III OI (severe fracturing and deformity, white sclerae, autosomal recessive inheritance). Orthopaedic complications predominated. Although only 6 of the 21 patients were adults, 16 were dwarfed, 14 had experienced more than 20 fractures and 19 had significant limb bowing. Seven were chair-bound and 9 walked with crutches or calipers.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical investigations of different forms of osteogenesis imperfecta. Evaluation of 44 cases

Forty-four patients with Osteogenesis Imperfecta (O.I.) were divided into groups on the basis of clinical and genetic criteria and the alterations in collagen and glycosaminoglycans (GAG) in the subjects of each group were examined. The largest group of patients as affected with a mild form of O.I. and showed an increased ratio of type III to type I collagen in skin and an increase of the ratio of hydroxylysine diglycoside to monoglycoside in skin collagen. The group of patients affected with a severe nonlethal form of O.I. appeared to be heterogeneous both from a clinical and from a biochemical point of view. A marked increase of the diglycoside to monoglycoside ratio was observed in skin and urine, whereas the ratio of type III to type I collagen in skin was within the normal range or significantly decreased. Some of these patients also showed alterations involving proteoglycans, e.g. in urinary GAGs a decreased galactosamine to glucosamine ratio could be demonstrated. Similar and more marked alterations involving both collagen and GAG metabolism were observed in five children affected with a lethal form of O.I.

[Lethal osteogenesis imperfecta. Anatomopathologic (optical and structural) study of 8 autopsy cases]

A pathologic review of lethal osteogenesis imperfecta was performed based in nine cases and mainly concerning eight cases with total postmortem study. One of the cases was classified as type III while all other were of type II. Emphasis is made on the high rate of prematurity, small for date and podalic presentation at birth. In those six cases of lower age lung hypoplasia was present. Well known findings in membranous or enchondral bones were confirmed in this series. Long bones showed characteristic bowings related to the nutrient artery point of entry. Among bone collagen fibres some of them were anomalous in shape or thickness but with normal striation. The only anomaly detected at the cartilaginous epiphysis was the increased wideness of the vascular channels because the existence of loose connective tissue and multivacuolated cells of unknown significance. At the growth plates the vascular channels were too much widened and of abnormal distribution. The proliferative and columnar zones showed poor cellular population and some condrocytes were abnormally vacuolated. The perichondrial ossification groove of Ranvier was absent or underdeveloped in all bones studied coexisting with epiphyseal-metaphyseal deformities. In our present cases, ocular, dental, dermal, cardiac valves and hepatic alterations have been detected. The weight increase and haematopoiesis of the liver was correlated to the hyperplasia and fibrosis of the bone marrow.

[Osteogenesis imperfecta. Up-to-date review (author's transl)]

Based on review of recent literature and in their own experience, authors point out basic concepts on alterations of collagen, emphasizing clinical and radiological data which differ types II and III in neonates.

Osteogenesis imperfecta: an expanding panorama of variants

Our concept of osteogenesis imperfecta (OI) has expanded considerably in the last decade. Both clinical and genetic studies on the one hand and biochemical studies on the other suggest considerable pathogenetic heterogeneity. Clinically, four broad groups can be distinguished. Two groups are characterized by dominant inheritance of osseous fragility with further heterogeneity determined by the presence or absence of opalescent dentin in families. A further two groups are characterized by autosomal recessive inheritance of severe or extreme bone fragility. An X-linked variety of OI also seems likely and a number of unique variants have been reported. These clinically defined groups are likely to represent classes of molecular defects. While there is evidence for disturbed regulation of collagen synthesis in some groups, it is possible that the primary defect in some cases may be in glycosaminoglycan/proteoglycan metabolism or even in skeletal cell metabolism leading to defective skeletal organization. Insight into the pathogenesis of these disorders will eventually permit specific therapy, prenatal diagnosis and more accurate genetic counseling for the osteogenesis imperfecta syndromes.

Scanning electron microscopy of teeth in dominant osteogenesis imperfecta: support for genetic heterogeneity

Scanning electron microscopic studies were performed on 25 deciduous and permanent teeth from members of 7 kindreds with dominant nonlethal osteogenesis imperfects (OI). Two families had normal teeth on clinical and radiological examination; five families had blue or brown opalescent teeth with specific radiologic findings. Enamel surfaces and prism organization were normal on all teeth. On fractured surfaces, the dentin tubules of normal teeth from patients with OI were evenly distributed and coursed regularly to the dentin-enamel junction. Opalescent teeth had few tubules and those present were short, narrow, and tortuous. Dentin calcification fronts of normal teeth were composed of many nodules with regularly spaced openings on their surfaces. Calcification fronts of opalescent teeth were composed of irregularly spaced, small nodules, which varied greatly in size and the nodules lacked tubule openings on their surfaces. The results of this study support the concept that at least two dominant forms of OI exist--one in which all individuals with IO have normal teeth, and the other in which all with OI have blue or brown opalescent teeth with characteristic changes on SEM.

Osteogenesis imperfecta. Review of the literature with presentation of 29 cases

Twelve families with 29 patients showing various patterns of osteogenesis imperfecta are described, along with the genetic, pathological, and clinical features. No abnormal blochemical features were found. It has been shown that the best treatment is prophylactic (such as intramedullary nailingy or supportive. There was no remarkable improvement from any form of medical treatment. These data are compared to those of other authors.