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At least 19 recordsLinked to original sources

[Osteogenesis imperfecta cystica (Fairbank)--a special form of osteogenesis imperfecta congenita (Vrolik) (author's transl)].

Two patients, aged 13 and 19 years, with osteogenesis imperfecta congenita (Vrolik) have been seen at the rehabilitation centre at Neckargemund. The younger patient showed the typical appearances of osteogenesis imperfecta cystica (Fairbank), while the older patient failed to show these changes in the skeleton. Contrary to the frequently expressed view that patients with osteogenesis imperfecta congenita always die in the perinatal period, they may survive for a considerable length of time. The change of osteogenesis imperfecta congenita (Vrolik) into osteogensis imperfecta cystica (Fairbank) has been described as a sequence in the occasional survivors by Spranger, but is not a necessary condition for survival. Osteogenesis imperfecta cystica should be regarded as an extremely rare special type of Vrolik's disease.

Adolescent

Early osteogenesis in compact bone isografts: a quantitative study of contributions of the different graft cells.

Isografts of cortical bone were tranplanted subcutaneously in the rat and the rate of osteogenesis 12 to 14 days later was assessed by measurement of 85Sr uptake and by histology. Some grafts were implanted complete whereas others had had one or more of their cellular components (viz. periosteum, endosteum, osteocytes, marrow) removed by mechanical or enzymatic pretreatment. From an analysis of the differences in osteogenesis between grafts devoid of different combinations of cellular components, the contribution of each component to osteogenesis was determined. The results indicate that the endosteal lining cells and marrow stroma together produce more than half of the new bone, the periosteal cells contribute about 30%, the osteocytes possibly make a small (10%) contribution, and the free, hemopoietic cells of the marrow make no significant contribution. Evidence about the relative contributions to osteogenesis of graft and host cells is reviewed and the possible osteogenetic role of bone marrow is discussed.

Animals

Osteogenesis imperfecta: evidence for the existence of an abnormal amino acid sequence in the molecule of dermal collagen.

A collagen-type pattern of peptide and amino acid spots was obtained when partial hydrolysates of normal human dermis were examined by a specially developed thin-layer chromatographic (TLC) 'finger-printing' technique. The pattern was consistent and independent of age and sex. Two clinically similar cases of osteogenesis imperfecta congenita gave identical patterns which differed in specific regions from those given by their age-matched, normal controls. A single case of osteogenesis imperfecta tarda showed the same overall pattern as the congenita cases. It is concluded that an abnormal amino acid sequence occurs in the collagen molecule of both types of osteogenesis imperfecta.

Adult

Valvular heart disease in osteogenesis imperfecta.

Aortic and mitral valve abnormalities have been reported which clearly appear to be related to the underlying connective tissue disorder in two patients, a father and daughter, with osteogenesis imperfecta. Although this appears to occur with a much lower prevalence and lesser severity than in the Marfan syndrome, the true prevalence of cardiac connective tissue involvement is not known, and the orthopedic complications of osteogenesis imperfecta may have overshadowed attention to cardiovascular abnormalities. In evaluating patients with osteogenesis imperfecta, careful attention should be paid to cardiovascular findings and if valvular lesions are noted, patients should be instructed regarding the need for antibiotic prophylaxis for dental and surgical procedures. The valvular lesions can progress, and regular follow-up cardiovascular evaluation should be planned. Finally, despite potential problems with tissue friability and healing and a possible tendency for increased bleeding, successful valve replacement can be carried out if necessitated by cardiac disability.

Adult

Mitochondrial granules in human osteoblasts with a reference to one case of osteogenesis imperfecta.

Electron-dense granules in mitochondria from prenatal human osteoblasts, postnatal human osteoblasts, and from osteoblasts derived from a child with osteogenesis imperfecta congenita are described. The mitochondrial granules were of about 600 A in diameter and were attached to the mitochondrial cristae. Sections of mitochondria from prenatal osteoblasts showed an average number of 10 granuales per mitochondrial section, whereas sections of mitochondria of postnatal osteoblasts showed only occasionally 1-2 granules per mitochondrial section. Mitochondria from osteoblasts derived from the child with an untreated osteogenesis imperfecta congenita showed an average number of 10 granules per mitochondrial section.

Adolescent

Evidence for abnormality of bone-matrix proteins in osteogenesis imperfecta.

Immunological and biochemical techniques demonstrated that the non-collagenous proteins of the organic matrix of bone were abnormal in quantity and composition in four children with osteogenesis imperfecta. This represents the main molecular difference found so far between bone in osteogenesis imperfecta and normal bone.

Adolescent

Dominant negative variants in KIF5B cause osteogenesis imperfecta via down regulation of mTOR signaling.

BACKGROUND: Kinesin motor proteins transport intracellular cargo, including mRNA, proteins, and organelles. Pathogenic variants in kinesin-related genes have been implicated in neurodevelopmental disorders and skeletal dysplasias. We identified de novo, heterozygous variants in KIF5B, encoding a kinesin-1 subunit, in four individuals with osteogenesis imperfecta. The variants cluster within the highly conserved kinesin motor domain and are predicted to interfere with nucleotide binding, although the mechanistic consequences on cell signaling and function are unknown. METHODS: To understand the in vivo genetic mechanism of KIF5B variants, we modeled the p.Thr87Ile variant that was found in two patients in the C. elegans ortholog, unc-116, at the corresponding position (Thr90Ile) by CRISPR/Cas9 editing and performed functional analysis. Next, we studied the cellular and molecular consequences of the recurrent p.Thr87Ile variant by microscopy, RNA and protein analysis in NIH3T3 cells, primary human fibroblasts and bone biopsy. RESULTS: C. elegans heterozygous for the unc-116 Thr90Ile variant displayed abnormal body length and motility phenotypes that were suppressed by additional copies of the wild type allele, consistent with a dominant negative mechanism. Time-lapse imaging of GFP-tagged mitochondria showed defective mitochondria transport in unc-116 Thr90Ile neurons providing strong evidence for disrupted kinesin motor function. Microscopy studies in human cells showed dilated endoplasmic reticulum, multiple intracellular vacuoles, and abnormal distribution of the Golgi complex, supporting an intracellular trafficking defect. RNA sequencing, proteomic analysis, and bone immunohistochemistry demonstrated down regulation of the mTOR signaling pathway that was partially rescued with leucine supplementation in patient cells. CONCLUSION: We report dominant negative variants in the KIF5B kinesin motor domain in individuals with osteogenesis imperfecta. This study expands the spectrum of kinesin-related disorders and identifies dysregulated signaling targets for KIF5B in skeletal development.

Animals

[Otosclerosis like bone in osteogenesis imperfecta tarda].

Bone like in otosclerosis from a 34-years-old man, from 33 years and 22 years old women, suffering from osteogenesis imperfecta tarda, with hardness of hearing in both ears were removed with chisel from the lower border of the oval window. After that a stapedectomy was accomplished. The stapedial crura have been genetically interrupted or broken, the footplate attached to the oval window. The bone from the border of the oval window was prepared for the histological examination. The specimens were coloured with Hematoxylin-Eosin and corresponding to Gomöri. In the bone similar cartilage osteoclasia and osteogenesis are rare. There are in the chondroosseous bone rooms filled with connective tissue. The diseased osseous labyrinth in osteo genesis imperfecta tarda must be regarded as a special morphogenetic formation of osteopsathyrosis.

Adult

Management of pregnancy in osteogenesis imperfecta: new perspectives.

Osteogenesis imperfecta during pregnancy presents increased risk to mother and fetus. In addition to the well-known skeletal changes, other recently recognized metabolic abnormalities also may lead to maternal and fetal problems during labor and delivery. A discussion of risk factors and their managment is presented. The importance of considering the possibility of fetal osteogenesis imperfecta is stressed, and cesarean section is presented as the method of choice for delivery. Important genetic factors including the lack of correlation between the severity of involvement of parent and offspring and the use of pyrophosphate analyses are discussed. An illustrative case is presented.

Adult

Hospitalization for child physical abuse before hospitalization for osteogenesis imperfecta or severe hemophilia: A nationwide cohort study in France.

BACKGROUND: Timely and accurate diagnosis of early child physical abuse (CPA) is crucial to avoid recurrence and protect victims. Ruling out differential diagnoses is also important to avoid misdiagnosis of CPA. We evaluated the risk of hospitalization for early CPA before hospitalization for its 2 main differential diagnoses: osteogenesis imperfecta (OI) and severe hemophilia (SH). METHODS: This population-based cohort study used the national administrative database covering all hospitals in France. We followed infants born from 2010 to 2019 until age 2. We identified infants with a first discharge code for early CPA, OI, and SH and calculated crude absolute and relative risks. RESULTS: Among the 6,315,216 infants included, 2088 (33/100,000 infants per year) were hospitalized for early CPA, 160 (3/100,000) for OI, and 402 (6/100,000) for SH before age 2. Among infants hospitalized for early CPA, 2085 (99.86 %) had no further hospitalization for OI or SH, 3 (0.14 %) were further hospitalized for OI with a 9-month median interval between hospitalizations, and 0 were further hospitalized for SH. The absolute risk of hospitalization for early CPA before hospitalization for OI was 1.9 % (3/160, 95 % confidence interval [CI] 0.39-5.38), and the relative risk as compared with infants without hospitalization for OI was 56.8 (95 % CI 18.5-174.3). CONCLUSIONS: The very low to null absolute risks of hospitalization for early CPA before OI or SH probably reflect excellent current clinical practices in ruling out differential diagnoses. A better implementation of existing guidelines could further shorten the time to diagnosis of OI before age 2.

Humans

A Novel Splice Variant in the COL1A1 Gene Leads to Exon 46 Skipping and Osteogenesis Imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a clinical and genetic disorder characterised by bone fragility, growth deficiency and skeletal deformity. Ninety per cent of OI cases are attributable to autosomal dominant variants in the COL1A1 and COL1A2 genes. METHODS: Candidate variants were identified and verified through trio whole-exome sequencing (trio-WES), copy number variation sequencing (CNV-seq) and Sanger sequencing. Minigene splicing assays were performed in HeLa and HEK293T cells with pcDNA3.1 and pcMINI-C vectors to investigate the function of the candidate variants. A systematic review of COL1A1 splicing variants and the corresponding genotype-phenotype spectrum was performed. RESULTS: Trio-WES revealed a novel heterozygous variant in the C-terminal region of the COL1A1 gene: NM_000088.4:c.3423+5G>A. Sanger sequencing confirmed the variant in both the proband (II-2) and her foetus (III-1) who were clinically suspected of having OI. The c.3423+5G>A variant causes complete skipping of Exon 46, as demonstrated by a minigene splicing assay. We retrieved 419 COL1A1 splicing variants from PubMed, excluded 15 without phenotypic data and 2 linked to Ehlers-Danlos syndrome and stratified the remaining 402 variants into three types on the basis of splice site location: (1) Variants at canonical splicing sites (77.8%, 313/402) mostly cause mild phenotypes, whereas a minority may be severe. (2) Intron variants in other locations, such as splice region variants (17.9%, 72/402), usually cause mild clinical phenotypes, and deep intronic splice variants (0.4%, 2/402) that may result in severe phenotypes. (3) Other variants (3.7%, 15/402), such as exon variants or fragment loss, are extremely rare. We also preliminarily discuss the mechanisms underlying phenotypic variability and the characteristics of C-terminal variants. CONCLUSIONS: This intron variant in COL1A1 was classified as likely pathogenic and was confirmed to disrupt COL1A1 expression. The summary analysis results also revealed a correlation among splicing variants, C-terminal region variants and disease, suggesting that variant location provides a useful framework for prognosis prediction.

Female

[Pathophysiology and metabolism in osteogenesis imperfecta (author's transl)].

The tissue changes in osteogenesis imperfecta apparently lie in the collagen and in the glycosaminoglycans. The collagen shows structural development disturbance and incomplete calcification. The tissue glycosaminoglycans are increased. The basis probably lies in a disturbed ATP metabolism (Solomons and Millar, 1973). An increased pyrophosphate concentration explains the decreased calcification and the structural changes. The increased osteolysis could be explained by increased quantities of cAMP.

Bone Resorption

Osteogenic sarcoma complicating osteogenesis imperfecta tarda.

We describe the case history of a 13 years old boy who developed osteogenic sarcoma of the left thigh, six years after diagnosis of osteogenesis imperfecta tarda with a positive family history. Only four other patients with this disease combination are reported in the literature. Preoperative treatment with high-dose Methotrexate caused marked tumor regression, as shown at examination of amputation material. The inter-relationships between the two disorders are discussed and the literature is briefly reviewed.

Adolescent

Heterotopic chondrogenesis and osteogenesis induced by transformed cells: use of nude mice as a model system.

A subline of HeLa cells was shown to induce cartilage and bone formation in congenitally athymic (nude) mice when injected intramuscularly. The chondrogenesis and osteogenesis observed was similar to that found when other inducing epithelia are injected intramuscularly into cortisone-treated mice. A tumorigenic SV40 T antigen-positive human-mouse somatic cell hybrid with human chromosomes C7 and C6 did not induce cartilage or bone formation under similar conditions. The nude mouse may thus provide a system in which to investigate experimental host-cell differentiation without the complications of immunosuppression.

Animals

Studies on the biology of fish bone. III. Ultrastructure of osteogenesis and resorption in osteocytic (cellular) and anosteocytic (acellular) bones.

The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned) Carassius auratus and the anosteocytic (acellular-boned) Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.

Animals

Inhibition of osteogenesis by bone mass in diffusion chamber cultures.

The effect of increased bone mass on osteogenesis was studied using the diffusion chamber culture of mouse distal radius as an experimental model. Two distal thirds of a mouse's radii were cultured in separate diffusion chambers in a recipient mouse; one chamber contained only a distal radius, but the other contained a distal radius plus two proximal radii and two ulnae. The DNA synthesis of osteogenetic cells was significantly inhibited in cultures with excess bone mass. The mean inhibition in labelling indices of epiphyseal plate chondrocytes was 27% and of periosteal cells 40%. The nature of this inhibition seems to be specific.

Animals