Heart disease in patients with osteogenesis imperfecta — A systematic review

Cardiovascular disease in adults with osteogenesis imperfecta: clinical characteristics, care recommendations, and research priorities identified using a modified Delphi technique

Osteogenesis imperfecta (OI) is a multisystem disorder most often caused by pathogenic variants in genes that encode type I collagen. Type I collagen is abundant not only in bone but also in multiple tissues including skin, tendons, cornea, blood vessels, and heart. Thus, OI can be expected to affect cardiovascular system, and there are numerous reports of cardiovascular disease (CVD) in people with OI. However, there is no consensus on how CVD in OI should be assessed or managed. To fill this gap, a multidisciplinary group was convened to develop clinical guidance. The work included a systematic review of the available literature and, using a modified Delphi approach, the development of a series of statements summarizing current knowledge. Fourteen clinical recommendations were developed to guide clinicians, patients, and stakeholders about an approach for CVD in adults with OI. This paper describes how the work was conducted and provides the background and rationale for each recommendation. Furthermore, we highlight knowledge gaps and suggest research priorities for the future study of CVD in OI.

Osteogenesis Imperfecta: Skeletal and Non-skeletal Challenges in Adulthood

Osteogenesis imperfecta (OI) is a Mendelian connective tissue disorder associated with increased bone fragility and other clinical manifestations most commonly due to abnormalities in production, structure, or post-translational modification of type I collagen. Until recently, most research in OI has focused on the pediatric population and much less attention has been directed at the effects of OI in the adult population. This is a narrative review of the literature focusing on the skeletal as well as non-skeletal manifestations in adults with OI that may affect the aging individual. We found evidence to suggest that OI is a systemic disease which involves not only the skeleton, but also the cardiopulmonary and gastrointestinal system, soft tissues, tendons, muscle, and joints, hearing, eyesight, dental health, and women's health in OI and potentially adds negative affect to health-related quality of life. We aim to guide clinicians as well as draw attention to obvious knowledge gaps and the need for further research in adult OI.

Extra-Skeletal Manifestations in Osteogenesis Imperfecta Mouse Models

Osteogenesis imperfecta (OI) is a rare heritable connective tissue disorder of skeletal fragility with an incidence of roughly 1:15,000. Approximately 85% of the pathogenic variants responsible for OI are in the type I collagen genes, COL1A1 and COL1A2, with the remaining pathogenic OI variants spanning at least 20 additional genetic loci that often involve type I collagen post-translational modification, folding, and intracellular transport as well as matrix incorporation and mineralization. In addition to being the most abundant collagen in the body, type I collagen is an important structural and extracellular matrix signaling molecule in multiple organ systems and tissues. Thus, OI disease-causing variants result not only in skeletal fragility, decreased bone mineral density (BMD), kyphoscoliosis, and short stature, but can also result in hearing loss, dentinogenesis imperfecta, blue gray sclera, cardiopulmonary abnormalities, and muscle weakness. The extensive genetic and clinical heterogeneity in OI has necessitated the generation of multiple mouse models, the growing awareness of non-skeletal organ and tissue involvement, and OI being more broadly recognized as a type I collagenopathy.This has driven the investigation of mutation-specific skeletal and extra-skeletal manifestations and broadened the search of potential mechanistic therapeutic strategies. The purpose of this review is to outline several of the extra-skeletal manifestations that have recently been characterized through the use of genetically and phenotypically heterogeneous mouse models of osteogenesis imperfecta, demonstrating the significant potential impact of OI disease-causing variants as a collagenopathy (affecting multiple organ systems and tissues), and its implications to overall health.

Whole-exome sequencing uncovers the genetic complexity of bicuspid aortic valve in families with early-onset complications

Bicuspid aortic valve (BAV) is the most common congenital heart lesion with an estimated population prevalence of 1%. We hypothesize that specific gene variants predispose to early-onset complications of BAV (EBAV). We analyzed whole-exome sequences (WESs) to identify rare coding variants that contribute to BAV disease in 215 EBAV-affected families. Predicted damaging variants in candidate genes with moderate or strong supportive evidence to cause developmental cardiac phenotypes were present in 107 EBAV-affected families (50% of total), including genes that cause BAV (9%) or heritable thoracic aortic disease (HTAD, 19%). After appropriate filtration, we also identified 129 variants in 54 candidate genes that are associated with autosomal-dominant congenital heart phenotypes, including recurrent deleterious variation of FBN2, MYH6, channelopathy genes, and type 1 and 5 collagen genes. These findings confirm our hypothesis that unique rare genetic variants drive early-onset presentations of BAV disease.

Respiratory insufficiency in an infant with osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a rare presentation in the pediatric population. Whilst orthopedic manifestations are well-publicised, the multiple respiratory complications and mechanisms of respiratory failure in more severe cases are less well described. We report the clinical, radiological and histopathological details of the case of an infant with genetically-confirmed OI (Type 2) and associated respiratory insufficiency, as well as summarise the relevant existing literature. This case highlights the importance of the recognition of clinical challenges associated with the management of respiratory complications in a patient with OI.

Sclerostin inhibition in rare bone diseases: Molecular understanding and therapeutic perspectives

Sclerostin emerges as a novel target for bone anabolic therapy in bone diseases. Osteogenesis imperfecta (OI) and X-linked hypophosphatemia (XLH) are rare bone diseases in which therapeutic potential of sclerostin inhibition cannot be ignored. In OI, genetic/pharmacologic sclerostin inhibition promoted bone formation of mice, but responses varied by genotype and age. Serum sclerostin levels were higher in young OI-I patients, while lower in adult OI-I/III/IV. It's worth investigating whether therapeutic response of OI to sclerostin inhibition could be clinically predicted by genotype and age. In XLH, preclinical/clinical data suggested factors other than identified FGF23 contributing to XLH. Higher levels of circulating sclerostin were detected in XLH. Sclerostin inhibition promoted bone formation in Hyp mice, while restored phosphate homeostasis in age-/gender-dependent manner. The role of sclerostin in regulating phosphate metabolism deserves investigation. Sclerostin/FGF23 levels of XLH patients with/without response to FGF23-antibody warrants study to develop precise sclerostin/FGF23 inhibition strategy or synergistic/additive strategy. Notably, OI patients were associated with cardiovascular abnormalities, so were XLH patients receiving conventional therapy. Targeting sclerostin loop3 promoted bone formation without cardiovascular risks. Further, blockade of sclerostin loop3-LRP4 interaction while preserving sclerostin loop2-ApoER2 interaction could be a potential precise sclerostin inhibition strategy for OI and XLH with cardiovascular safety. The Translational Potential of this Article. Preclinical data on the molecular understanding of sclerostin inhibition in OI and therapeutic efficacy in mouse models of different genotypes, as well as clinical data on serum sclerostin levels in patients with different phenotypes of OI, were reviewed and discussed. Translationally, it would facilitate to develop clinical prediction strategies (e.g. based on genotype and age, not just phenotype) for OI patients responsive to sclerostin inhibition. Both preclinical and clinical data suggested sclerostin as another factor contributing to XLH, in addition to the identified FGF23. The molecular understanding and therapeutic effects of sclerostin inhibition on both promoting bone anabolism and improving phosphate homostasis in Hyp mice were reviewed and discussed. Translationaly, it would facilitate the development of precise sclerostin/FGF23 inhibition strategy or synergistic/additive strategy for the treatment of XLH. Cardiovascular risk could not be ruled out during sclerostin inhibition treatment, especially for OI and XLH patients with cardiovascular diseases history and cardiovascular abnormalities. Studies on the role of sclerostin in inhiting bone formation and protecting cardiovascular system were reviewed and discussed. Translationaly, blockade of sclerostin loop3-LRP4 interaction while preserving sclerostin loop2-ApoER2 interaction could be a potential precise sclerostin inhibition strategy for OI and XLH with cardiovascular safety.

Echocardiographic abnormalities and joint hypermobility in Chinese patients with Osteogenesis imperfecta

BACKGROUND

Very little is known about the characteristics of echocardiographic abnormalities and joint hypermobility in Chinese patients with osteogenesis imperfecta (OI). The aim of our study was to investigate the characteristics, prevalence and correlation of echocardiographic abnormalities and joint hypermobility in Chinese patients with OI.

METHODS

A cross-sectional comparative study was conducted in pediatric and adult OI patients who were matched in age and sex with healthy controls. Transthoracic echocardiography was performed in all patients and controls, and parameters were indexed for body surface area (BSA). The Beighton score was used to evaluate the degree of joint hypermobility.

RESULTS

A total of 48 patients with OI (25 juveniles and 23 adults) and 129 age- and sex-matched healthy controls (79 juveniles and 50 adults) were studied. Four genes (COL1A1, COL1A2, IFITM5, and WNT1) and 39 different mutation loci were identified in our study. Mild valvular regurgitation was the most common cardiac abnormality: mild mitral and tricuspid regurgitation was found in 12% and 36% of pediatric OI patients, respectively; among 23 OI adults, 13% and 17% of patients had mild mitral and tricuspid regurgitation, respectively, and 4% had mild aortic regurgitation. In multiple regression analysis, OI was the key predictor of left atrium diameter (LAD) (β=-3.670, P < 0.001) and fractional shortening (FS) (β = 3.005, P = 0.037) in juveniles, whereas for adults, OI was a significant predictor of LAD (β=-3.621, P < 0.001) and left ventricular mass (LVM) (β = 58.928, P < 0.001). The percentages of generalized joint hypermobility in OI juveniles and adults were 56% and 20%, respectively. Additionally, only in the OI juvenile group did the results of the Mann‒Whitney U test show that the degree of joint hypermobility was significantly different between the echocardiographic normal and abnormal groups (P = 0.004).

CONCLUSIONS

Mild valvular regurgitation was the most common cardiac abnormality in both OI juveniles and adults. Compared with OI adults, OI juveniles had more prevalent and wider joint hypermobility. Echocardiographic abnormalities may imply that the impairment of type I collagen is more serious in OI. Baseline echocardiography should be performed in OI patients as early as possible.

Is Osteogenesis Imperfecta Associated with Cardiovascular Abnormalities? A Systematic Review of the Literature

Osteogenesis imperfecta (OI) is a rare genetic disorder caused by abnormal collagen type I production. While OI is primarily characterized by bone fragility and deformities, patients also have extraskeletal manifestations, including an increased risk of cardiovascular disease. This review provides a comprehensive overview of the literature on cardiovascular diseases in OI patients in order to raise awareness of this understudied clinical aspect of OI and support clinical guidelines. In accordance with the PRISMA guidelines, a systematic literature search in PubMed, Embase, Web of Science and Scopus was conducted that included articles from the inception of these databases to April 2023. Valvular disease, heart failure, atrial fibrillation, and hypertension appear to be more prevalent in OI than in control individuals. Moreover, a larger aortic root was observed in OI compared to controls. Various cardiovascular diseases appear to be more prevalent in OI than in controls. These cardiovascular abnormalities are observed in all types of OI and at all ages, including young children. As there are insufficient longitudinal studies, it is unknown whether these abnormalities are progressive in nature in OI patients. Based on these findings, we would recommend referring individuals with OI to a cardiologist with a low-threshold.

Whole Exome Sequencing Uncovers the Genetic Complexity of Bicuspid Aortic Valve in Families with Early Onset Complications

Bicuspid Aortic Valve (BAV) is the most common adult congenital heart lesion with an estimated population prevalence of 1%. We hypothesize that early onset complications of BAV (EBAV) are driven by specific impactful genetic variants. We analyzed whole exome sequences (WES) to identify rare coding variants that contribute to BAV disease in 215 EBAV families. Predicted pathogenic variants of causal genes were present in 111 EBAV families (51% of total), including genes that cause BAV (8%) or heritable thoracic aortic disease (HTAD, 17%). After appropriate filtration, we also identified 93 variants in 26 novel genes that are associated with autosomal dominant congenital heart phenotypes, including recurrent deleterious variation of FBN2, MYH6, channelopathy genes, and type 1 and 5 collagen genes. These findings confirm our hypothesis that unique rare genetic variants contribute to early onset complications of BAV disease.

Emerging Landscape of Osteogenesis Imperfecta Pathogenesis and Therapeutic Approaches

Osteogenesis imperfecta (OI) is an uncommon genetic disorder characterized by shortness of stature, hearing loss, poor bone mass, recurrent fractures, and skeletal abnormalities. Pathogenic variations have been found in over 20 distinct genes that are involved in the pathophysiology of OI, contributing to the disorder's clinical and genetic variability. Although medications, surgical procedures, and other interventions can partially alleviate certain symptoms, there is still no known cure for OI. In this Review, we provide a comprehensive overview of genetic pathogenesis, existing treatment modalities, and new developments in biotechnologies such as gene editing, stem cell reprogramming, functional differentiation, and transplantation for potential future OI therapy.

Osteogenesis imperfecta: a cross-sectional study of skeletal and extraskeletal features in a large cohort of Italian patients

Introduction

The present study aims to describe a large cohort of Italian patients affected by osteogenesis imperfecta, providing a picture of the clinical bony and non-bony features and the molecular background to improve knowledge of the disease to inform appropriate management in clinical practice.

Methods

A total of 568 subjects (from 446 unrelated Italian families) affected by osteogenesis imperfecta who received outpatient care at Istituto Ortopedico Rizzoli from 2006 to 2021 were considered in the present study.

Results

Skeletal and extraskeletal features were analyzed showing a lower height (mean z-scores equal to -1.54 for male patients and -1.47 for female patients) compared with the general Italian population. Half of the patient population showed one or more deformities, and most of the patients had suffered a relatively low number of fractures (<10). An alteration in the sclera color was identified in 447 patients. Similarly, several extraskeletal features, like deafness, dental abnormalities, and cardiac problems, were investigated. Additionally, inheritance and genetic background were evaluated, showing that most of the patients have a positive family history and the majority of pathogenic variants detected were on collagen genes, as per literature.

Conclusion

This study supports the definition of a clear picture of the heterogeneous clinical manifestations leading to variable severity in terms of skeletal and extra-skeletal traits and of the genetic background of an Italian population of osteogenesis imperfecta patients. In this perspective, this clearly highlights the crucial role of standardized and structured collection of high-quality data in disease registries particularly in rare disease scenarios, helping clinicians in disease monitoring and follow-up to improve clinical practice.

A case-control study of early-stage radiological markers of endothelial dysfunction and cardiovascular findings in patients with osteogenesis imperfecta: genotype-phenotype correlations

OBJECTIVES

Osteogenesis imperfecta (OI) is a disease caused by defective collagen synthesis. Collagen type 1 is found in many structures in the cardiovascular system. Endothelial dysfunction, which develops prior to the emergence of structural and clinical signs of atherosclerosis, is believed to play a key role in atherogenesis. Endothelial dysfunction may be detected presymptomatically by non-invasive radiologic methods, such as flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT). These modalities may provide early indicators of endothelial dysfunction. This cross-sectional comparative study aimed to investigate early-stage radiological markers of endothelial dysfunction and cardiovascular diseases in OI patients and healthy controls and to investigate the correlation of findings with OI genotype.

METHODS

Thirty patients diagnosed with OI were paired with thirty healthy age- and gender-matched controls and echocardiogram findings were compared.

RESULTS

None of the patients had known underlying cardiovascular disease. The mean age was 13.18 ± 2.91 years. According to Sillence classification, 15 patients had type 1 OI, 10 had type III, and 5 had type IV. Mean CIMT in the OI group was higher in the control group (OI group: 0.42 ± 0.06 vs. healthy controls: 0.34 ± 0.04 mm, p<0.01), and mean FMD percent was lower in the patient group (p<0.01). Left ventricular ejection fraction was 78.97 ± 10.32 vs. 77.56 ± 8.50 %, (OI group: 7.00 ± 3.06 vs. healthy controls: 12.14 ± 1.99, p=0.56), and fractional shortening was 42.68 ± 11.94 vs. 40.23 ± 7.99 %, (p=0.35), in OI patients and controls, respectively.

CONCLUSIONS

Pediatric patients with OI without clinical signs of cardiovascular abnormality had significantly worse CIMT and FMD findings than healthy controls. However, no difference was determined when comparing left ventricular ejection fraction or fractional shortening. OI patients may need to be screened for cardiovascular system complications starting from an early age.

Whole-Body Metabolism and the Musculoskeletal Impacts of Targeting Activin A and Myostatin in Severe Osteogenesis Imperfecta

Mutations in the COL1A1 and COL1A2 genes, which encode type I collagen, are present in around 85%-90% of osteogenesis imperfecta (OI) patients. Because type I collagen is the principal protein composition of bones, any changes in its gene sequences or synthesis can severely affect bone structure. As a result, skeletal deformity and bone frailty are defining characteristics of OI. Homozygous oim/oim mice are utilized as models of severe progressive type III OI. Bone adapts to external forces by altering its mass and architecture. Previous attempts to leverage the relationship between muscle and bone involved using a soluble activin receptor type IIB-mFc (sActRIIB-mFc) fusion protein to lower circulating concentrations of activin A and myostatin. These two proteins are part of the TGF-β superfamily that regulate muscle and bone function. While this approach resulted in increased muscle masses and enhanced bone properties, adverse effects emerged due to ligand promiscuity, limiting clinical efficacy and obscuring the precise contributions of myostatin and activin A. In this study, we investigated the musculoskeletal and whole-body metabolism effect of treating 5-week-old wildtype (Wt) and oim/oim mice for 11 weeks with either control antibody (Ctrl-Ab) or monoclonal anti-activin A antibody (ActA-Ab), anti-myostatin antibody (Mstn-Ab), or a combination of ActA-Ab and Mstn-Ab (Combo). We demonstrated that ActA-Ab treatment minimally impacts muscle mass in oim/oim mice, whereas Mstn-Ab and Combo treatments substantially increased muscle mass and overall lean mass regardless of genotype and sex. Further, while no improvements in cortical bone microarchitecture were observed with all treatments, minimal improvements in trabecular bone microarchitecture were observed with the Combo treatment in oim/oim mice. Our findings suggest that individual or combinatorial inhibition of myostatin and activin A alone is insufficient to robustly improve femoral biomechanical and microarchitectural properties in severely affected OI mice. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

The patient clinical journey and socioeconomic impact of osteogenesis imperfecta: a systematic scoping review

BACKGROUND

Osteogenesis imperfecta (OI) is a rare heritable connective tissue disorder primarily characterised by skeletal deformity and fragility, and an array of secondary features. The purpose of this review was to capture and quantify the published evidence relating specifically to the clinical, humanistic, and economic impact of OI on individuals, their families, and wider society.

METHODS

A systematic scoping review of 11 databases (MEDLINE, MEDLINE in-progress, EMBASE, CENTRAL, PsycINFO, NHS EED, CEA Registry, PEDE, ScHARRHUd, Orphanet and Google Scholar), supplemented by hand searches of grey literature, was conducted to identify OI literature published 1st January 1995-18th December 2021. Searches were restricted to English language but without geographical limitations. The quality of included records was assessed using the AGREE II checklist and an adapted version of the JBI cross-sectional study checklist.

RESULTS

Of the identified 7,850 records, 271 records of 245 unique studies met the inclusion criteria; overall, 168 included records examined clinical aspects of OI, 67 provided humanistic data, 6 reported on the economic impact of OI, and 30 provided data on mixed outcomes. Bone conditions, anthropometric measurements, oral conditions, diagnostic techniques, use of pharmacotherapy, and physical functioning of adults and children with OI were well described. However, few records included current care practice, diagnosis and monitoring, interactions with the healthcare system, or transition of care across life stages. Limited data on wider health concerns beyond bone health, how these concerns may impact health-related quality of life, in particular that of adult men and other family members, were identified. Few records described fatigue in children or adults. Markedly few records provided data on the socioeconomic impact of OI on patients and their caregivers, and associated costs to healthcare systems, and wider society. Most included records had qualitative limitations.

CONCLUSION

Despite the rarity of OI, the volume of recently published literature highlights the breadth of interest in the OI field from the research community. However, significant data gaps describing the experience of OI for individuals, their families, and wider society warrant further research to capture and quantify the full impact of OI.

From Genetics to Clinical Implications: A Study of 675 Dutch Osteogenesis Imperfecta Patients

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder that causes bone fragility due to pathogenic variants in genes responsible for the synthesis of type I collagen. Efforts to classify the high clinical variability in OI led to the Sillence classification. However, this classification only partially takes into account extraskeletal manifestations and the high genetic variability. Little is known about the relation between genetic variants and phenotype as of yet. The aim of the study was to create a clinically relevant genetic stratification of a cohort of 675 Dutch OI patients based on their pathogenic variant types and to provide an overview of their respective medical care demands. The clinical records of 675 OI patients were extracted from the Amsterdam UMC Genome Database and matched with the records from Statistics Netherlands (CBS). The patients were categorized based on their harbored pathogenic variant. The information on hospital admissions, outpatient clinic visits, medication, and diagnosis-treatment combinations (DTCs) was compared between the variant groups. OI patients in the Netherlands appear to have a higher number of DTCs, outpatient clinic visits, and hospital admissions when compared to the general Dutch population. Furthermore, medication usage seems higher in the OI cohort in comparison to the general population. The patients with a COL1A1 or COL1A2 dominant negative missense non-glycine substitution appear to have a lower health care need compared to the other groups, and even lower than patients with COL1A1 or COL1A2 haploinsufficiency. It would be useful to include the variant type in addition to the Sillence classification when categorizing a patient's phenotype.

Cardiovascular abnormalities and its correlation with genotypes of children with osteogenesis imperfecta

BACKGROUND AND OBJECTIVES

Osteogenesis imperfecta (OI) is a rare disorder of abnormal production or modification of type I collagen, which is caused by mutations in COL1A1, COL1A2 or other genes. We investigate the cardiac abnormalities and its correlation with pathogenic mutations in OI children.

METHODS

A cross-sectional comparative study was completed in a relatively large sample of OI children, who were matched in body surface area (BSA) with healthy controls. All echocardiography was performed by experienced cardiologists using Vivid 7 equipment (GE Medical Systems, Horton, Norway). The resting standard 12-lead electrocardiogram (ECG) were obtained in OI patients by FX-8600 machine. Skeletal phenotypes of OI patients were evaluated, including information of bone fractures, deformities, motility, and bone mineral density (BMD). Pathogenic mutations of OI were detected by a next-generation sequencing panel and confirmed by Sanger sequencing.

RESULTS

A total of 69 OI children and 42 healthy children matched in BSA were enrolled. Abnormalities of echocardiography were found in 6 OI children, including enlarged left atrium (n=5), increased internal diameter of the left ventricle (n=1), who all carried the COL1A1 mutation. Mild regurgitation of mitral or tricuspid valves was observed in 26 OI patients. Abnormal ECG manifestations were found in 8 OI children, including deep Q wave, T wave change, premature ventricular complexes, short P-R interval, incomplete bundle branch block and high voltage of left ventricular. Compared with healthy controls, OI children had significant larger values in the main pulmonary artery (1.84 vs 1.60 cm, P < 0.01), left atrial diameter (2.58 vs 2.11 cm, P < 0.001), left ventricular internal dimension at end-diastolic (LVEDd) (3.85 vs 3.50 cm, P < 0.05) and lower left ventricular ejection fraction (LVEF) (68.40% vs 71.74%, P < 0.01). Moreover, OI patients with COL1A1 mutation tended to have greater main pulmonary artery, larger diameters of left atrial and LVEDd, and lower LVEF than healthy controls. COL1A1 mutation was correlated to dilated MPA (β = 1.557, P < 0.01), LAD (β = 3.915, P < 0.001), and LVEDd (β = 2.714, P < 0.01), and decreased LVEF (β = -3.249, P < 0.01).

CONCLUSIONS

Cardiovascular alterations were identified in OI children, including increased dimensions of the main pulmonary artery and left chamber, and low LVEF. The cardiovascular abnormalities seemed to be correlated to COL1A1 mutation and defects of type I collagen, which expanded our understandings of the cardiac phenotypes of OI children.

Osteoarthritis in osteogenesis imperfecta: A nationwide register-based cohort study

BACKGROUND

Osteogenesis Imperfecta (OI) is a genetic disease characterized by skeletal fragility. Collagen type 1 is found in many tissues and collagen abnormalities may result in organ specific symptomatology. Musculoskeletal pain is a known issue for patients with OI, osteoarthritis (OA) can be a likely cause. Only few studies have investigated the relationship between OI and OA but demonstrated a greater propensity in OI patients to develop rapidly progressing OA. Therefore, we wanted to investigate if OA is more frequent in patients with OI compared to the general population.

OBJECTIVE

To evaluate the risk of osteoarthritis in patients with OI.

DESIGN

A Danish nationwide, population-based and register-based longitudinal open cohort study.

PARTICIPANTS

From 1977 to 2019, all patients registered with an OI diagnosis and a reference population matched on age and sex 5:1.

MEASUREMENTS

Sub-hazard ratios for any, hip, and knee osteoarthritis comparing the OI cohort to the reference population.

RESULTS

We identified 907 patients with OI (493 women) and included 4535 patients in the reference population (2465 women). The Sub Hazard Ratio was 2.20 [95% CI 1.73-2.79] for any osteoarthritis with 11.4% of the OI population and 5.4% of the reference population being registered. We found lower incidences of upper extremity joint OA compared to lower joint OA, but upper extremity joint OA was significantly more frequent in the OI population 2.1% vs 0.6%, SHR 3.19 [95% CI 1.78-5.70].

CONCLUSION

Patients with OI have a higher risk of OA than the reference population.

MINIABSTRACT

Osteogenesis Imperfecta (OI) is a hereditary connective tissue disorder with skeletal fragility and extraskeletal manifestations. Osteoarthritis is a frequent joint disease and the incidence increases with age. In a population-register-based study, the risk of osteoarthritis was higher in patients with OI at an earlier age compared to a reference population.

Collagen transport and related pathways in Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI) comprises a heterogeneous group of patients who share bone fragility and deformities as the main characteristics, albeit with different degrees of severity. Phenotypic variation also exists in other connective tissue aspects of the disease, complicating disease classification and disease course prediction. Although collagen type I defects are long established as the primary cause of the bone pathology, we are still far from comprehending the complete mechanism. In the last years, the advent of next generation sequencing has triggered the discovery of many new genetic causes for OI, helping to draw its molecular landscape. It has become clear that, in addition to collagen type I genes, OI can be caused by multiple proteins connected to different parts of collagen biosynthesis. The production of collagen entails a complex process, starting from the production of the collagen Iα1 and collagen Iα2 chains in the endoplasmic reticulum, during and after which procollagen is subjected to a plethora of posttranslational modifications by chaperones. After reaching the Golgi organelle, procollagen is destined to the extracellular matrix where it forms collagen fibrils. Recently discovered mutations in components of the retrograde transport of chaperones highlight its emerging role as critical contributor of OI development. This review offers an overview of collagen regulation in the context of recent gene discoveries, emphasizing the significance of transport disruptions in the OI mechanism. We aim to motivate exploration of skeletal fragility in OI from the perspective of these pathways to identify regulatory points which can hint to therapeutic targets.

Extracellular Matrix in Vascular Disease, Part 2/4: JACC Focus Seminar

Medium-sized and large arteries consist of 3 layers: the tunica intima, tunica media, and tunica adventitia. The tunica media accounts for the bulk of the vessel wall and is the chief determinant of mechanical compliance. It is primarily composed of circumferentially arranged layers of vascular smooth muscle cells that are separated by concentrically arranged elastic lamellae; a form of extracellular matrix (ECM). The tunica media is separated from the tunica intima and tunica adventitia, the innermost and outermost layers, respectively, by the internal and external elastic laminae. This second part of a 4-part JACC Focus Seminar discusses the contributions of the ECM to vascular homeostasis and pathology. Advances in genetics and proteomics approaches have fostered significant progress in our understanding of vascular ECM. This review highlights the important role of the ECM in vascular disease and the prospect of translating these discoveries into clinical disease biomarkers and potential future therapies.

Cardiopulmonary Status in Adults with Osteogenesis Imperfecta: Intrinsic Lung Disease May Contribute More Than Scoliosis

BACKGROUND

Osteogenesis imperfecta (OI) is a heterogeneous group of collagen-related disorders characterized by osteopenia, bone fractures, spine deformities, and nonskeletal complications. Cardiopulmonary complications are the major cause of morbidity and mortality in adults with OI. The cause of such problems was often attributed solely to the presence of large scoliosis curves affecting pulmonary function and, indirectly, cardiovascular health. However, recent studies suggest this may not be the case. Therefore, determining the relationships and causative agents of cardiopulmonary problems in patients with OI, specifically pulmonary impairment, is important to improving the overall wellbeing, quality of life, and survival of these patients.

QUESTIONS/PURPOSES

(1) Is cardiopulmonary fitness in OI solely related to the presence of scoliosis? (2) What is the prevalence of heart and lung complications in this adult population? (3) Does the presence of pulmonary impairment impact quality of life in adults with OI?

METHODS

This is a prospective observational cross-sectional study. Within 1 year, each participant (n = 30) completed pulmonary function testing, echocardiogram, ECG, chest CT, AP spine radiography, and quality-of-life assessments (SF-36, St. George's Respiratory Questionnaire, Functional Outcomes of Sleep Questionnaire, and Pittsburgh Sleep Quality Index). In terms of pulmonary function, we differentiated restrictive and obstructive physiology using the ratio of forced expiratory volume over one second to forced vital capacity (FEV1/FVC), with restrictive lung physiology defined as FEV1/FVC > 0.8 and obstructive lung physiology as FEV1/FVC < 0.7. Spine radiographs were evaluated for scoliosis. Chest CT images were reviewed to qualitatively assess the lungs. The statistical analysis involved a Kruskall-Wallis test with Bonferroni's correction and a bivariate correlation analysis using Spearman's rho correlation coefficient (p < 0.05).

RESULTS

Sixteen of 23 participants with restrictive lung physiology had scoliosis; their ages ranged from 19 years to 67 years. There was no correlation between the magnitude of the scoliosis curve and deficient pulmonary function (R = 0.08; p = 0.68). Seven participants had normal pulmonary function. The average scoliosis curve was 44 ± 29°. Thirteen participants had abnormal ECG findings while 10 had abnormal echocardiogram results. All but two individuals with abnormal chest CT results were found to have bronchial wall thickening. There were no differences in pulmonary or cardiac findings between OI types, except for FVC and total lung capacity, which were lower in individuals with Type III OI than in those with other types of OI. FEV1/FVC correlated with St. George's Respiratory Questionnaire (R = 0.429; p = 0.02) but not with Functional Outcomes of Sleep Questionnaire (R = -0.26; p = 0.19) or SF-36 scores (physical component summary: R = -0.037, p = 0.85; mental component summary: R = -0.204, p = 0.29).

CONCLUSIONS

The lack of a relationship between decreased pulmonary function and the severity of scoliosis suggests that restrictive lung physiology in this population is likely because of factors intrinsic to OI and not entirely because of thoracic cage deformities. The fact that pulmonary impairment influences self-perceived quality of life exemplifies how detrimental such complications may be to everyday functioning. This also reinforces the importance of determining the underlying cause of cardiopulmonary impairment in this population to set clear clinical guidelines of care.

LEVEL OF EVIDENCE

Level II, prognostic study.

Echocardiographic study in children with osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta is a collagen type I bone disorder. Recently, extra-skeletal manifestations have been described, including many cardiovascular alterations. This study aims to report echocardiogram study in children with osteogenesis imperfecta compared to a control group.

METHODS

A cross-sectional comparative study took place in the Reference Center for Treatment of Osteogenesis Imperfecta in Southern Brazil. Fifty-four patients with osteogenesis imperfecta were paired with 54 controls, based on body surface area, and echocardiogram findings were compared.

RESULTS

All cases were asymptomatic for cardiac manifestations. The case group presented significant larger values in aortic diameter, left atrium diameter, left ventricule end-diastolic diameter, left ventricule end-systolic diameter, and right ventricle diameter compared with the control group. The analysis considering the severity of osteogenesis imperfecta shows that in mild osteogenesis imperfecta, the aortic diameter (p < 0.001), left atrium diameter (p = 0.002), left ventricule end-diastolic diameter (p = 0.001), left ventricule end-systolic diameter (p = 0.026), and right ventricle diameter (p < 0.001) were significantly larger than in the control group. Patients with moderate/severe osteogenesis imperfecta had similar results, with aortic diameter (p < 0.001), left atrium diameter (p < 0.001), left ventricule end-diastolic diameter (p = 0.013), and left ventricule end-systolic diameter (0.004) statistically larger than controls. Twenty-six (48.1%) of the cases had physiological tricuspid regurgitation and in controls this finding was observed in eight (14.8%) (p < 0.001).

CONCLUSION

Children with osteogenesis imperfecta presented cardiac function within the normal pattern, but dimensions of left ventricular dimensions were increased compared to the ones of the controls.

High-Grade Spindle Cell Sarcoma of the Heart: A Rare Cause of Mitral Valve Disease

A young female with pulmonary congestion suspected to be secondary to mitral valve disease with left atrial appendage thrombus was given therapy for heart failure and anticoagulation. Subsequent multimodality imaging with echocardiography and magnetic resonance imaging established an accurate but rare diagnosis of spindle cell sarcoma of the heart. (Level of Difficulty: Intermediate.)

Aortic aneurysm/dissection and osteogenesis imperfecta: Four new families and review of the literature

Osteogenesis imperfecta (OI) is the commonest form of heritable bone fragility. It is mainly characterized by fractures, hearing loss and dentinogenesis imperfecta. OI patients are at increased risk of cardiovascular disease of variable severity. Aortic aneurysm/dissection is one of the rarer but potentially serious cardiovascular complications of OI. So far, only six patients with aortic dissection and OI have been reported. As such, present OI diagnostic guidelines do not recommend systematic screening of patients for aortopathy. Here, we report on the clinical and molecular characteristics of three new OI patients and one additional patient with a first degree relative who presented with aortic dissection and/or aneurysm surgery. This observation further opens up the discussion on the need for and extent of cardiovascular screening in adult patients with OI.

Genotype-phenotype correlation study in 364 osteogenesis imperfecta Italian patients

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.

Osteogenesis imperfecta - A clinical update

Osteogenesis imperfecta (OI) is the most common inherited form of bone fragility and includes a heterogenous group of genetic disorders which most commonly result from defects associated with type 1 collagen. 85%-90% of cases are inherited in an autosomal dominant manner and are caused by mutations in the COL1A1 and COL1A2 genes, leading to quantitative or qualitative defects in type 1 collagen. In the last decade, defects in several other proteins involved in the normal processing of type 1 collagen have been described. Recent advances in genetics have called for reconsideration of the classification of OI, however, most recent classifications align with the classic clinical classification by Sillence. The hallmark of the disease is bone fragility but other tissues are also affected. Intravenous bisphosphonates (BPs) are the most widely used intervention, having significant favorable effects regarding areal bone mineral density (BMD) and vertebral reshaping following fractures in growing children. BPs have a modest effect in long bone fracture incidence, their effects in adults with OI concerns only BMD, while there are reports of subtrochanteric fractures resembling atypical femoral fractures. Other therapies showing promising results include denosumab, teriparatide, sclerostin inhibition, combination therapy with antiresorptive and anabolic drugs and TGF-β inhibition. Gene targeting approaches are under evaluation. More research is needed to delineate the best therapeutic approach in this heterogeneous disease.

Osteogenesis imperfecta

Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation.

Mortality and Causes of Death in Patients With Osteogenesis Imperfecta: A Register-Based Nationwide Cohort Study

Osteogenesis imperfecta (OI) is a hereditary connective tissue disease that causes frequent fractures. Little is known about causes of death and length of survival in OI. The objective of this work was to calculate the risk and cause of death, and the median survival time in patients with OI. This study was a Danish nationwide, population-based and register-based cohort study. We used National Patient Register data from 1977 until 2013 with complete long-term follow-up. Participants comprised all patients registered with the diagnosis of OI from 1977 until 2013, and a reference population matched five to one to the OI cohort. We calculated hazard ratios for all-cause mortality and subhazard ratios for cause-specific mortality in a comparison of the OI cohort and the reference population. We also calculated all-cause mortality hazard ratios for males, females, and age groups (0 to 17.99 years, 18.00 to 34.99 years, 35.00 to 54.99 years, 55.00 to 74.99 years, and >75 years). We identified 687 cases of OI (379 women) and included 3435 reference persons (1895 women). A total of 112 patients with OI and 257 persons in the reference population died during the observation period. The all-cause mortality hazard ratio between the OI cohort and the reference population was 2.90. The median survival time for males with OI was 72.4 years, compared to 81.9 in the reference population. The median survival time for females with OI was 77.4 years, compared to 84.5 years in the reference population. Patients with OI had a higher risk of death from respiratory diseases, gastrointestinal diseases, and trauma. We were limited by the lack of clinical information about phenotype and genotype of the included patients. Patients with OI had a higher mortality rate throughout their life compared to the general population. © 2016 American Society for Bone and Mineral Research.

Cardiovascular disease in patients with osteogenesis imperfecta - a nationwide, register-based cohort study

BACKGROUND

Osteogenesis imperfecta (OI) is a hereditary connective tissue disease often due to mutations in genes coding for type 1 collagen. Collagen type 1 is important in the development of the heart and vasculature. Little is known about the risk of cardiovascular disease (CVD) in OI.

OBJECTIVE

To investigate the risk of symptomatic CVD in OI.

DESIGN

A Danish nationwide, population-based and register-based longitudinal open cohort study.

PARTICIPANTS

All patients registered with the diagnosis of OI from 1977 to 2013 and a reference population matched 5:1 to the OI cohort.

MEASUREMENTS

Sub-hazard ratios for mitral and aortic valve regurgitation, atrial fibrillation and flutter, heart failure and vascular aneurisms and dissections comparing the OI cohort to the reference population.

RESULTS

We identified 687 cases with OI (379 women) and included 3435 reference persons (1895 women). The SHR was 6.3 [95% CI: 2.5-15.5] for mitral valve regurgitation, 4.5 [95% CI: 1.4-13.9] for aortic valve regurgitation, 1.7 [95% CI: 1.1-2.8] for atrial fibrillation/flutter, and 2.3 [95% CI: 1.4-3.7] for heart failure. The SHRs were not increased arterial aneurisms or dissections.

LIMITATION

Our results were limited by lacking clinical information about phenotype and genotype of the included patients.

CONCLUSION

We confirm that patients with OI have an increased risk of CVD compared to the general population. This held true even when adjusting for factors that are known to contribute to development of these diseases. Our results suggest that the collagenopathy seen in OI may be part of the pathogenesis of CVD in OI.