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Current Opinion in Pediatrics Dec 2019The purpose of this review is to outline the current understanding of the molecular mechanisms and natural history of osteogenesis imperfecta, and to describe the... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to outline the current understanding of the molecular mechanisms and natural history of osteogenesis imperfecta, and to describe the development of new treatments for this disorder.
RECENT FINDINGS
The introduction of next-generation sequencing technology has led to better understanding of the genetic cause of osteogenesis imperfecta and enabled cost-effective and timely diagnosis via expanded gene panels and exome or genome sequencing. Clinically, despite genetic heterogeneity, different forms of osteogenesis imperfecta share similar features that include connective tissue and systemic manifestations in addition to bone fragility. Thus, the goals of treatment in osteogenesis imperfecta extend beyond decreasing the risk of fracture, to include the maximization of growth and mobility, and the management of extraskeletal complications. The standard of care in pediatric patients is bisphosphonates therapy. Ongoing preclinical studies in osteogenesis imperfecta mouse models and clinical studies in individuals with osteogenesis imperfecta have been instrumental in the development of new and targeted therapeutic approaches, such as sclerostin inhibition and transforming growth factor-β inhibition.
SUMMARY
Osteogenesis imperfecta is a skeletal dysplasia characterized by bone fragility and extraskeletal manifestations. Better understanding of the mechanisms of osteogenesis imperfecta will enable the development of much needed targeted therapies to improve the outcome in affected individuals.
Topics: Adaptor Proteins, Signal Transducing; Animals; Child; Diphosphonates; Humans; Mice; Molecular Targeted Therapy; Osteogenesis Imperfecta
PubMed: 31693577
DOI: 10.1097/MOP.0000000000000813 -
European Journal of Endocrinology Oct 2020Osteogenesis imperfecta (OI) is an inherited skeletal dysplasia characterized by bone fragility and skeletal deformities. While the majority of cases are associated with... (Review)
Review
Osteogenesis imperfecta (OI) is an inherited skeletal dysplasia characterized by bone fragility and skeletal deformities. While the majority of cases are associated with pathogenic variants in COL1A1 and COL1A2, the genes encoding type I collagen, up to 25% of cases are associated with other genes that function within the collagen biosynthesis pathway or are involved in osteoblast differentiation and bone mineralization. Clinically, OI is heterogeneous in features and variable in severity. In addition to the skeletal findings, it can affect multiple systems including dental and craniofacial abnormalities, muscle weakness, hearing loss, respiratory and cardiovascular complications. A multi-disciplinary approach to care is recommended to address not only the fractures, reduced mobility, growth and bone pain but also other extra-skeletal manifestations. While bisphosphonates remain the mainstay of treatment in OI, new strategies are being explored, such as sclerostin inhibitory antibodies and TGF beta inhibition, to address not only the low bone mineral density but also the inherent bone fragility. Studies in animal models have expanded the understanding of pathomechanisms of OI and, along with ongoing clinical trials, will allow to develop better therapeutic approaches for these patients.
Topics: Animals; Endocrinology; Fractures, Bone; Humans; Osteogenesis; Osteogenesis Imperfecta
PubMed: 32621590
DOI: 10.1530/EJE-20-0299 -
Medicina (Kaunas, Lithuania) May 2021Osteogenesis imperfecta (OI), or brittle bone disease, is a heterogeneous disorder characterised by bone fragility, multiple fractures, bone deformity, and short... (Review)
Review
Osteogenesis imperfecta (OI), or brittle bone disease, is a heterogeneous disorder characterised by bone fragility, multiple fractures, bone deformity, and short stature. OI is a heterogeneous disorder primarily caused by mutations in the genes involved in the production of type 1 collagen. Severe OI is perinatally lethal, while mild OI can sometimes not be recognised until adulthood. Severe or lethal OI can usually be diagnosed using antenatal ultrasound and confirmed by various imaging modalities and genetic testing. The combination of imaging parameters obtained by ultrasound, computed tomography (CT), and magnetic resource imaging (MRI) can not only detect OI accurately but also predict lethality before birth. Moreover, genetic testing, either noninvasive or invasive, can further confirm the diagnosis prenatally. Early and precise diagnoses provide parents with more time to decide on reproductive options. The currently available postnatal treatments for OI are not curative, and individuals with severe OI suffer multiple fractures and bone deformities throughout their lives. In utero mesenchymal stem cell transplantation has been drawing attention as a promising therapy for severe OI, and a clinical trial to assess the safety and efficacy of cell therapy is currently ongoing. In the future, early diagnosis followed by in utero stem cell transplantation should be adopted as a new therapeutic option for severe OI.
Topics: Adult; Collagen Type I; Female; Genetic Testing; Humans; Mesenchymal Stem Cell Transplantation; Mutation; Osteogenesis Imperfecta; Pregnancy
PubMed: 34068551
DOI: 10.3390/medicina57050464 -
Biomolecules Oct 2021Osteogenesis Imperfecta (OI) is a group of connective tissue disorders with a broad range of phenotypes characterized primarily by bone fragility. The prevalence of OI... (Review)
Review
Osteogenesis Imperfecta (OI) is a group of connective tissue disorders with a broad range of phenotypes characterized primarily by bone fragility. The prevalence of OI ranges from about 1:15,000 to 1:20,000 births. Five types of the disease are commonly distinguished, ranging from a mild (type I) to a lethal one (type II). Types III and IV are severe forms allowing survival after the neonatal period, while type V is characterized by a mild to moderate phenotype with calcification of interosseous membranes. In most cases, there is a reduction in the production of normal type I collagen (col I) or the synthesis of abnormal collagen as a result of mutations in col I genes. Moreover, mutations in genes involved in col I synthesis and processing as well as in osteoblast differentiation have been reported. The currently available treatments try to prevent fractures, control symptoms and increase bone mass. Commonly used medications in OI treatment are bisphosphonates, Denosumab, synthetic parathyroid hormone and growth hormone for children therapy. The main disadvantages of these therapies are their relatively weak effectiveness, lack of effects in some patients or cytotoxic side effects. Experimental approaches, particularly those based on stem cell transplantation and genetic engineering, seem to be promising to improve the therapeutic effects of OI.
Topics: Cellular Reprogramming; Endoplasmic Reticulum Stress; Humans; Models, Biological; Osteogenesis Imperfecta; Phenotype; Stem Cell Transplantation
PubMed: 34680126
DOI: 10.3390/biom11101493 -
Endocrine Reviews Jan 2022Osteogenesis imperfecta (OI) is a phenotypically and genetically heterogeneous skeletal dysplasia characterized by bone fragility, growth deficiency, and skeletal... (Review)
Review
Osteogenesis imperfecta (OI) is a phenotypically and genetically heterogeneous skeletal dysplasia characterized by bone fragility, growth deficiency, and skeletal deformity. Previously known to be caused by defects in type I collagen, the major protein of extracellular matrix, it is now also understood to be a collagen-related disorder caused by defects in collagen folding, posttranslational modification and processing, bone mineralization, and osteoblast differentiation, with inheritance of OI types spanning autosomal dominant and recessive as well as X-linked recessive. This review provides the latest updates on OI, encompassing both classical OI and rare forms, their mechanism, and the signaling pathways involved in their pathophysiology. There is a special emphasis on mutations in type I procollagen C-propeptide structure and processing, the later causing OI with strikingly high bone mass. Types V and VI OI, while notably different, are shown to be interrelated by the interferon-induced transmembrane protein 5 p.S40L mutation that reveals the connection between the bone-restricted interferon-induced transmembrane protein-like protein and pigment epithelium-derived factor pathways. The function of regulated intramembrane proteolysis has been extended beyond cholesterol metabolism to bone formation by defects in regulated membrane proteolysis components site-2 protease and old astrocyte specifically induced-substance. Several recently proposed candidate genes for new types of OI are also presented. Discoveries of new OI genes add complexity to already-challenging OI management; current and potential approaches are summarized.
Topics: Collagen; Collagen Type I; Humans; Interferons; Mutation; Osteogenesis Imperfecta; Signal Transduction
PubMed: 34007986
DOI: 10.1210/endrev/bnab017 -
The Journal of Clinical Investigation Apr 2022BACKGROUNDCurrently, there is no disease-specific therapy for osteogenesis imperfecta (OI). Preclinical studies demonstrate that excessive TGF-β signaling is a...
BACKGROUNDCurrently, there is no disease-specific therapy for osteogenesis imperfecta (OI). Preclinical studies demonstrate that excessive TGF-β signaling is a pathogenic mechanism in OI. Here, we evaluated TGF-β signaling in children with OI and conducted a phase I clinical trial of TGF-β inhibition in adults with OI.METHODSHistology and RNA-Seq were performed on bones obtained from children. Gene Ontology (GO) enrichment assay, gene set enrichment analysis (GSEA), and Ingenuity Pathway Analysis (IPA) were used to identify dysregulated pathways. Reverse-phase protein array, Western blot, and IHC were performed to evaluate protein expression. A phase I study of fresolimumab, a TGF-β neutralizing antibody, was conducted in 8 adults with OI. Safety and effects on bone remodeling markers and lumbar spine areal bone mineral density (LS aBMD) were assessed.RESULTSOI bone demonstrated woven structure, increased osteocytes, high turnover, and reduced maturation. SMAD phosphorylation was the most significantly upregulated GO molecular event. GSEA identified the TGF-β pathway as the top activated signaling pathway, and IPA showed that TGF-β1 was the most significant activated upstream regulator mediating the global changes identified in OI bone. Treatment with fresolimumab was well-tolerated and associated with increases in LS aBMD in participants with OI type IV, whereas participants with OI type III and VIII had unchanged or decreased LS aBMD.CONCLUSIONIncreased TGF-β signaling is a driver pathogenic mechanism in OI. Anti-TGF-β therapy could be a potential disease-specific therapy, with dose-dependent effects on bone mass and turnover.TRIAL REGISTRATIONClinicalTrials.gov NCT03064074.FUNDINGBrittle Bone Disorders Consortium (U54AR068069), Clinical Translational Core of Baylor College of Medicine Intellectual and Developmental Disabilities Research Center (P50HD103555) from National Institute of Child Health and Human Development, USDA/ARS (cooperative agreement 58-6250-6-001), and Sanofi Genzyme.
Topics: Adult; Bone Density; Bone and Bones; Child; Humans; Lumbar Vertebrae; Osteogenesis Imperfecta; Transforming Growth Factor beta
PubMed: 35113812
DOI: 10.1172/JCI152571 -
Advances in Clinical and Experimental... Jun 2021Skeletal dysplasias are a heterogeneous group of congenital bone and cartilage disorders with a genetic etiology. The current classification of skeletal dysplasias... (Review)
Review
Skeletal dysplasias are a heterogeneous group of congenital bone and cartilage disorders with a genetic etiology. The current classification of skeletal dysplasias distinguishes 461 diseases in 42 groups. The incidence of all skeletal dysplasias is more than 1 in every 5000 newborns. The type of dysplasia and associated abnormalities affect the lethality, survival and long-term prognosis of skeletal dysplasias. It is crucial to distinguish skeletal dysplasias and correctly diagnose the disease to establish the prognosis and achieve better management. It is possible to use prenatal ultrasonography to observe predictors of lethality, such as a bell-shaped thorax, short ribs, severe femoral shortening, and decreased lung volume. Individual lethal or life-limiting dysplasias may have more or less specific features on prenatal ultrasound. The prenatal features of the most common skeletal dysplasias, such as thanatophoric dysplasia, osteogenesis imperfecta type II, achondrogenesis, and campomelic dysplasia, are discussed in this article. Less frequent dysplasias, such as asphyxiating thoracic dystrophy, fibrochondrogenesis, atelosteogenesis, and homozygous achondroplasia, are also discussed.
Topics: Female; Humans; Infant, Newborn; Osteochondrodysplasias; Osteogenesis Imperfecta; Pregnancy; Receptor, Fibroblast Growth Factor, Type 3; Thanatophoric Dysplasia; Ultrasonography, Prenatal
PubMed: 34019743
DOI: 10.17219/acem/134166 -
European Journal of Human Genetics :... Jul 2019Osteogenesis imperfecta (OI) is a rare genetic disorder of the connective tissue and 90% of cases are due to dominant mutations in COL1A1 and COL1A2 genes. To increase... (Clinical Trial)
Clinical Trial
Osteogenesis imperfecta (OI) is a rare genetic disorder of the connective tissue and 90% of cases are due to dominant mutations in COL1A1 and COL1A2 genes. To increase OI disease knowledge and contribute to patient follow-up management, a homogeneous Italian cohort of 364 subjects affected by OI types I-IV was evaluated. The study population was composed of 262 OI type I, 24 type II, 39 type III, and 39 type IV patients. Three hundred and nine subjects had a type I collagen affecting function mutations (230 in α1(I) and 79 in α2(I)); no disease-causing changes were noticed in 55 patients. Compared with previous genotype-phenotype OI correlation studies, additional observations arose: a new effect for α1- and α2-serine substitutions has been pointed out and heart defects, never considered before, resulted associated to quantitative mutations (P = 0.043). Moreover, some different findings emerged if compared with previous literature; especially, focusing the attention on the lethal form, no association with specific collagen regions was found and most of variants localized in the previously reported "lethal clusters" were causative of OI types I-IV. Some discrepancies have been highlighted also considering the "50-55 nucleotides rule," as well as the relationship between specific collagen I mutated region and the presence of dentinogenesis imperfecta and/or blue sclera. Despite difficulties still present in defining clear rules to predict the clinical outcome in OI patients, this study provides new pieces for completing the puzzle, also thanks to the inclusion of clinical signs never considered before and to the large number of OI Italian patients.
Topics: Adult; Amino Acid Substitution; Child, Preschool; Collagen Type I; Collagen Type I, alpha 1 Chain; Female; Genotype; Humans; Infant; Italy; Male; Mutation, Missense; Osteogenesis Imperfecta; Phenotype; Young Adult
PubMed: 30886339
DOI: 10.1038/s41431-019-0373-x -
The Pan African Medical Journal 2021
Topics: Bone and Bones; Humans; Osteogenesis; Osteogenesis Imperfecta
PubMed: 34909086
DOI: 10.11604/pamj.2021.40.98.31815