Bisphosphonate therapy for osteogenesis imperfecta

The IMPACT Survey: the economic impact of osteogenesis imperfecta in adults

BACKGROUND

The IMPACT survey aimed to elucidate the humanistic, clinical and economic burden of osteogenesis imperfecta (OI) on individuals with OI, their families, caregivers and wider society. Research methodology, demographics and initial insights from the survey have been previously reported. The cost of illness (healthcare resource use, productivity loss, out-of-pocket spending) and drivers of the economic impact of OI are reported here.

METHODS

IMPACT was an international mixed-methods online survey in eight languages (fielded July-September 2021) targeting adults (aged ≥ 18 years) or adolescents (aged ≥ 12-17 years) with OI, caregivers with or without OI and other close relatives. Survey domains included demographics, socioeconomic factors, clinical characteristics, treatment patterns, quality of life and health economics. The health economic domain for adults, which included questions on healthcare resource use, productivity loss and out-of-pocket spending, was summarised. Regression and pairwise analyses were conducted to identify independent drivers and associations with respondent characteristics.

RESULTS

Overall, 1,440 adults with OI responded to the survey. Respondents were mostly female (70%) and from Europe (63%) with a median age of 43 years. Within a 12-month period, adults with OI reported visiting a wide range of healthcare professionals. Two-thirds (66%) of adults visited a hospital, and one-third (33%) visited the emergency department. The mean total number of diagnostic tests undergone by adults within these 12 months was 8.0. Adults had undergone a mean total of 11.8 surgeries up to the time point of the survey. The proportions of adults using queried consumables or services over 12 months ranged from 18-82%, depending on the type of consumable or service. Most adults (58%) were in paid employment, of which nearly one-third (29%) reported missing a workday. Of the queried expenses, the mean total out-of-pocket spending in 4 weeks was €191. Respondent characteristics such as female sex, more severe self-reported OI and the experience of fractures were often associated with increased economic burden.

CONCLUSION

IMPACT provides novel insights into the substantial cost of illness associated with OI on individuals, healthcare systems and society at large. Future analyses will provide insights into country-specific economic impact, humanistic impact and the healthcare journey of individuals with OI.

Dickkopf-1 (DKK1) blockade mitigates osteogenesis imperfecta (OI) related bone disease

BACKGROUND

The current treatment of osteogenesis imperfecta (OI) is imperfect. Our study thus delves into the potential of using Dickkopf-1 antisense (DKK1-AS) to treat OI.

METHODS

We analysed serum DKK1 levels and their correlation with lumbar spine and hip T-scores in OI patients. Comparative analyses were conducted involving bone marrow stromal cells (BMSCs) and bone tissues from wild-type mice, untreated OI mice, and OI mice treated with DKK1-ASor DKK1-sense (DKK1-S).

RESULTS

Significant inverse correlations were noted between serum DKK1 levels and lumbar spine (correlation coefficient = - 0.679, p = 0.043) as well as hip T-scores (correlation coefficient = - 0.689, p = 0.042) in OI patients. DKK1-AS improved bone mineral density (p = 0.002), trabecular bone volume/total volume fraction (p < 0.001), trabecular separation (p = 0.010), trabecular thickness (p = 0.001), trabecular number (p < 0.001), and cortical thickness (p < 0.001) in OI mice. DKK1-AS enhanced the transcription of collagen 1α1, osteocalcin, runx2, and osterix in BMSC from OI mice (all p < 0.001), resulting in a higher von Kossa-stained matrix area (p < 0.001) in ex vivo osteogenesis assays. DKK1-AS also reduced osteoclast numbers (p < 0.001), increased β-catenin and T-cell factor 4 immunostaining reactivity (both p < 0.001), enhanced mineral apposition rate and bone formation rate per bone surface (both p < 0.001), and decreased osteoclast area (p < 0.001) in OI mice. DKK1-AS upregulated osteoprotegerin and downregulated nuclear factor-kappa B ligand transcription (both p < 0.001). Bone tissues from OI mice treated with DKK1-AS exhibited significantly higher breaking force compared to untreated OI mice (p < 0.001).

CONCLUSIONS

Our study elucidates that DKK1-AS has the capability to enhance bone mechanical properties, restore the transcription of osteogenic genes, promote osteogenesis, and inhibit osteoclastogenesis in OI mice.

Influence of zoledronic acid and pamidronate on tooth eruption in children with osteogenesis imperfecta

INTRODUCTION

Osteogenesis imperfecta (OI) is a congenital disease comprising a heterogeneous group of inherited connective tissue disorders. The main treatment in children is bisphosphonate therapy. Previous animal studies have shown that bisphosphonates delay tooth eruption. The aim of this study is to determine whether patients with OI treated with pamidronate and/or zoledronic acid have a delayed eruption age compared to a control group of healthy children.

METHODS

An ambispective longitudinal cohort study evaluating the age of eruption of the first stage mixed dentition in a group of children with OI (n = 37) all treated with intravenous bisphosphonates compared with a group of healthy children (n = 89). Within the study group, the correlation (Pearson correlation test) between the type of medication administered (pamidronate and/or zoledronic acid) and the chronology of tooth eruption is established, as well as the relationship between the amount of cumulative dose received and tooth eruption.

RESULTS

The age of eruption of the study group was significantly delayed compared to the age of eruption of the control group for molars and lateral incisors (p < 0.05). Patients who received higher cumulative doses had a delayed eruption age compared to those with lower cumulative doses (p < 0.05). There is a high positive correlation between age of delayed tooth eruption and Zoledronic acid administration.

CONCLUSION

Patients with OI have a delayed eruption of the 1st stage mixed dentition compared to a control group of healthy children. This delayed eruption is directly related to the cumulative dose of bisphosphonates and the administration of zoledronic ac.

Demographics and medical burden of osteogenesis imperfecta: a nationwide database analysis

The epidemiological data on osteogenesis imperfecta (OI) in Asia is limited. This study, representing the first comprehensive epidemiological investigation on OI in Taiwan, reveals high medical resource utilization and underscores the importance of early diagnosis to enhance care quality.

INTRODUCTION

This study examines osteogenesis imperfecta, a hereditary connective tissue disorder causing pediatric fractures and limb deformities, using a nationwide database from Taiwan to analyze clinical features and medical burden.

METHODS

The study identified validated OI patients from the Catastrophic Illness Registry in the National Health Insurance Research Database from 2008 to 2019. Demographic data and medical resource utilization were analyzed. A multivariate Cox model assessed the influence of sex, validation age, and comorbidities.

RESULTS

319 OI patients (M/F = 153/166) were identified, with 58% validated before age 20. Prevalence and incidence were 0.8-1.3/100,000 and 0.02-0.09/100,000, respectively, with higher rates in the pediatric demographic. In the study period, 69.6% of the patients had admission history, primarily to pediatric and orthopedic wards. The median admission number was 3, with a median length of stay of 12 days and a median inpatient cost of approximately 3,163 USD during the period. Lower limb fractures were the main reason for hospitalization. 57% of OI patients received bisphosphonate treatment. The leading causes of mortality were OI-related deaths, neurovascular disease, and cardiovascular disease. The median age of validation in the non-survival group was significantly higher compared to the survival group (33 vs. 14 years), and patients validated during childhood required more inpatient fracture surgeries than those validated during adulthood.

CONCLUSION

This study provides comprehensive real-world evidence on the clinical characteristics and high medical resource utilization of OI patients in a low prevalence region like Taiwan. Early diagnosis is crucial for improving care quality and enhancing health outcomes.

Pseudoarthrosis of the Distal Humerus in Pediatric Osteogenesis Imperfecta Patients: A Case Series and Literature Review

Osteogenesis imperfecta (OI) is a rare skeletal disorder that increases a patient's susceptibility to bone fracture. One complication commonly associated with fractures in this population is the occurrence of non-union leading to pseudoarthrosis. In this case series, three cases of non-union of the distal humerus leading to pseudoarthrosis in the pediatric OI population are presented. One case presents a successful attempt at treatment, one case presents a failed attempt at treatment, and the third case presents a patient's refusal to get treated. Furthermore, a literature review highlighting other institutions' attempts, successes, and failures at treating this clinical entity is presented. Combining the data retrieved from our institution and others, this review demonstrates that there is currently no standard for treating these patients. Additionally, based on the small case series and literature review presented in this article, definitive guidelines for the treatment of pseudoarthrosis of the distal humerus in pediatric OI patients cannot be outlined. However, our findings suggest that both non-surgical and surgical treatments could be viable options for patients with asymptomatic pseudoarthrosis of the distal humerus.

Ventriculosubgaleal shunt placement for hydrocephalus in osteogenesis imperfecta with novel compound heterozygous CRTAP variants

Osteogenesis imperfecta is characterized by frequent fractures, bone deformities, and other systemic symptoms. Severe osteogenesis imperfecta may progress to hydrocephalus; however, treatment strategies for this complication remain unclear. Here, we describe severe osteogenesis imperfecta in an infant with symptomatic hydrocephalus treated with ventriculosubgaleal shunt placement. Targeted next-generation sequencing revealed novel compound heterozygous CRTAP variants, i.e., NM_006371.5, c.241 G > T, p.(Glu81*) and NM_006371.5, c.923-2_932del. We suggest that ventriculosubgaleal shunt placement is an effective and safe treatment for hydrocephalus in patients with severe osteogenesis imperfecta.

Zoledronic Acid Accelerates ER Stress-Mediated Inflammation by Increasing PDE4B Expression in Bisphosphonate-Related Osteonecrosis of the Jaw

Long-term administration of bisphosphonates can lead to a significant side effect known as bisphosphonate-related osteonecrosis of the jaw (BRONJ). Although macrophage-mediated inflammation has been established as an important factor in BRONJ, the underlying mechanism remains elusive. In the current study, the roles of endoplasmic reticulum (ER) stress in zoledronic acid (ZOL)-induced inflammation were analyzed in macrophages, and the regulatory mechanism of ER stress activation was next investigated. An in vitro model of BRONJ was established by treating RAW264.7 cells with ZOL. The activation of ER stress was analyzed by western blotting and transmission electron microscopy, and inflammation was assessed by quantitative real-time PCR and enzyme-linked immunosorbent assay. ER stress was significantly activated in ZOL-treated macrophages, and inhibition of ER stress by TUDCA, an ER stress inhibitor, suppressed ZOL-induced inflammation in macrophages. Mechanistically, phosphodiesterase 4B (PDE4B) was significantly increased in ZOL-treated macrophages. Forced expression of PDE4B promoted ER stress and inflammation, whereas PDE4B knockdown decreased ZOL-induced ER stress and inflammation in macrophages. More importantly, PDE4B inhibitor could improve ZOL-induced BRONJ in vivo. These data suggest that ZOL accelerates ER stress-mediated inflammation in BRONJ by increasing PDE4B expression. PDE4B inhibition may represent a potential therapeutic strategy for BRONJ. Subsequent research should concentrate on formulating medications that selectively target PDE4B, thereby mitigating the risk of BRONJ in patients undergoing bisphosphonate treatment.

Current and Developing Pharmacologic Agents for Improving Skeletal Health in Adults with Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility largely caused by defects in structure, synthesis, or post-translational processing of type I collagen. Drugs currently used to improve skeletal health in OI were initially developed to treat osteoporosis and clinical trials are ongoing to study their effectiveness in OI adults. Additionally, novel bone-protective agents are in preclinical studies and various phases of OI clinical trials. This review summarizes current knowledge on available pharmacologic agents and current drug trials involving OI participants. A PubMed online database search of all study types published in the English language using the terms "osteogenesis imperfecta," "OI," and "brittle bone disease" was performed in August 2022. Articles screened were restricted to adults. A ClinicalTrials.gov database search of all studies involving "osteogenesis imperfecta" was performed in August 2023. Although clinical trial data are limited, bisphosphonates and teriparatide may be useful in improving bone mineral density. As of yet, no clinical trials are available that adequately evaluate the usefulness of current therapies in reducing fracture risk. Several therapeutics, including teriparatide, setrusumab, anti-TGF-β antibodies, and allogeneic stem cells, are being studied in clinical trials. Preclinical studies involving Dickkopf-1 antagonists present promising data in non-OI bone disease, and could be useful in OI. Research is ongoing to improve therapeutic options for adults with OI and clinical trials involving gene-editing may be possible in the coming decade.

Fatality owing to pulmonary hemorrhage following pamidronate disodium administration in a neonate with osteogenesis imperfecta type 2: A case report

We report the case of a patient with osteogenesis imperfecta (OI) who developed pulmonary hemorrhage 4 d after pamidronate disodium (PA) administration, despite a relatively stable respiratory status. Bisphosphonates are introduced to reduce osteoclast activity and are now widely used in patients with OI. Bisphosphonates are typically well-tolerated in children, and the standard of care involves cyclic intravenous administration of PA. However, in practice, there is limited experience with the use of PA for severe OI during the neonatal period, and its safety remains uncertain. This report aimed to describe the respiratory events potentially associated with PA in a neonatal patient with OI type 2, suggesting that serious life-threatening complications of pulmonary hemorrhage may occur after PA administration. Further studies are required to assess the relationship between pulmonary hemorrhage and PA administration, aiming to enhance prophylaxis measures.

Non-steroidal Anti-inflammatory Drug (NSAID)-, Potassium Supplement-, Bisphosphonate-, and Doxycycline-Mediated Peptic Ulcer Effects: A Narrative Review

Peptic ulcers are a common condition that arises from an imbalance between acid production and gastroduodenal protective factors. Various drugs, including non-steroidal anti-inflammatory drugs (NSAIDs), potassium supplements, bisphosphonates, and doxycycline, can increase the development of peptic ulcers. NSAIDs are one of the most common medications prescribed for pain relief, and they also inhibit the formation of cyclooxygenase-1 (COX-1). COX-1 helps in the production of mucus that lines the stomach, so by inhibiting COX-1, NSAIDs reduce the mucus produced by the stomach and increase the likelihood of gastric ulcer formation. Additionally, NSAIDs are acidic, and increasing the amount of any acid in the stomach can result in promoting ulcer development. Potassium supplements are used to reduce the effects of hypertension, decrease the development of kidney stones, and treat hypokalemia. The various types of transporters and channels used to move potassium across cell membranes increase hydrogen being pumped, increasing gastric acid production and ulcer formation. Bisphosphonates are used to treat a variety of skeletal disorders that require inhibition of osteoclast activity. Nitric oxide (NO) has been shown to have a therapeutic effect on gastric ulcers, and some bisphosphonates have been shown to decrease the production of nitric oxide, resulting in increased damage to the gastric mucosa. Finally, doxycycline is a broad-spectrum tetracycline antibiotic that is typically used to treat anthrax poisoning, skin lesions, and sexually transmitted diseases. A harmful adverse effect of doxycycline is the formation of peptic and gastric ulcers related to the drug being highly acidic once it has dissolved.

Discrepancies in the Phenotypical Classification of Osteogenesis Imperfecta in a Patient with COL1A2 Mutation: A Case Report

BACKGROUND Osteogenesis imperfecta (OI) is a rare genetic disease that results from mutations in type 1 collagen (COL1) or its interacting proteins. Such mutations lead to defects in bone structure, causing brittle bones, short stature, hearing loss, and dental problems, among others. The current classification system arranges OI into types according to a clinical phenotype that includes the severity of the disease and a combination of specific features, such as blue sclerae and dental abnormalities. CASE REPORT Here, we present a clinical report of a 3-year-old boy diagnosed with OI in utero who has been followed by our pediatric clinic postnatally. The patient was born with multiple bone fractures, a small head circumference, and blue sclerae and later had a concomitant diagnosis of dentinogenesis imperfecta (DI). Soon after birth, the patient was started on bisphosphonate and calcium/vitamin D treatment. The patient's OI type was inconclusive due to the dramatic difference between perinatal and postnatal phenotypes, the presence of blue sclerae, and the additional diagnosis of DI. The patient experienced only 1 new bone fracture postnatally, had normal anthropometric measurements except for short stature, and was healthy. CONCLUSIONS This clinical case is unique owing to the dramatic perinatal and mild postnatal OI phenotypes. This and the unique combination of postnatal features demonstrate that classical OI typing could be inconclusive in atypical disease presentation. This case may demonstrate a new classification possibility outside the current OI nomenclature. However, the potential beneficial role of pharmacological treatment in the clinical outcome of OI cannot be excluded.

Protocol of a randomised trial of teriparatide followed by zoledronic acid to reduce fracture risk in adults with osteogenesis imperfecta

INTRODUCTION

Osteogenesis imperfecta (OI) is a rare genetic disease associated with multiple fractures throughout life. It is often treated with osteoporosis medications but their effectiveness at preventing fractures is unknown. The Treatment of Osteogenesis Imperfecta with Parathyroid Hormone and Zoledronic Acid trial will determine if therapy with teriparatide (TPTD) followed by zoledronic acid (ZA) can reduce the risk of clinical fractures in OI.

METHODS AND ANALYSIS

Individuals aged ≥18 years with a clinical diagnosis of OI are eligible to take part. At baseline, participants will undergo a spine X-ray, and have bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) at the spine and hip. Information on previous fractures and previous bone targeted treatments will be collected. Questionnaires will be completed to assess pain and other aspects of health-related quality of life (HRQoL). Participants will be randomised to receive a 2-year course of TPTD injections 20 µg daily followed by a single intravenous infusion of 5 mg ZA, or to receive standard care, which will exclude the use of bone anabolic drugs. Participants will be followed up annually, have a repeat DXA at 2 years and at the end of study. Spine X-rays will be repeated at the end of study. The duration of follow-up will range between 2 and 8 years. The primary endpoint will be new clinical fractures confirmed by X-ray or other imaging. Secondary endpoints will include participant reported fractures, BMD and changes in pain and HRQoL.

ETHICS AND DISSEMINATION

The study received ethical approval in December 2016. Following completion of the trial, a manuscript will be submitted to a peer-reviewed journal. The results will inform clinical practice by determining if TPTD/ZA can reduce the risk of fractures in OI compared with standard care.

TRIAL REGISTRATION NUMBER

ISRCTN15313991.

What the pediatric endocrinologist needs to know about skeletal dysplasia, a primer

Children with skeletal dysplasia are frequently referred to pediatric endocrinologists due to short stature. These children may present with disproportionate growth or medical histories that point to a skeletal dysplasia. This primer will discuss when to be concerned about skeletal dysplasia, the initial steps in evaluation for a skeletal dysplasia, and new therapies that are either recently approved or in development.

Schnurri-3 inhibition rescues skeletal fragility and vascular skeletal stem cell niche pathology in a mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding type collagen. While it is well known that OI reflects defects in the activity of bone-forming osteoblasts, it is currently unclear whether OI also reflects defects in the many other cell types comprising bone, including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility. Here, we find that numbers of skeletal stem cells (SSCs) and skeletal arterial endothelial cells (AECs) are augmented in Col1a2oim/oim mice, a well-studied animal model of moderate to severe OI, suggesting that disruption of a vascular SSC niche is a feature of OI pathogenesis. Moreover, crossing Col1a2oim/oim mice to mice lacking a negative regulator of skeletal angiogenesis and bone formation, Schnurri 3 (SHN3), not only corrected the SSC and AEC phenotypes but moreover robustly corrected the bone mass and spontaneous fracture phenotypes. As this finding suggested a strong therapeutic utility of SHN3 inhibition for the treatment of OI, a bone-targeting AAV was used to mediate Shn3 knockdown, rescuing the Col1a2oim/oim phenotype and providing therapeutic proof-of-concept for targeting SHN3 for the treatment of OI. Overall, this work both provides proof-of-concept for inhibition of the SHN3 pathway and more broadly addressing defects in the stem/osteoprogentior niche as is a strategy to treat OI.

Pharmacological options in the treatment of osteogenesis imperfecta: A comprehensive review of clinical and potential alternatives

Osteogenesis imperfecta (OI) is a genetically heterogeneous connective tissue disorder characterized by bone fragility and different extra-skeletal manifestations. The severity of these manifestations makes it possible to classify OI into different subtypes based on the main clinical features. This review aims to outline and describe the current pharmacological alternatives for treating OI, grounded on clinical and preclinical reports, such as antiresorptive agents, anabolic agents, growth hormone, and anti-TGFβ antibody, among other less used agents. The different options and their pharmacokinetic and pharmacodynamic properties will be reviewed and discussed, focusing on the variability of their response and the molecular mechanisms involved to attain the main clinical goals, which include decreasing fracture incidence, improving pain, and promoting growth, mobility, and functional independence.

Classification of osteogenesis imperfecta: Importance for prophylaxis and genetic counseling

Osteogenesis imperfecta (OI) is a genetically heterogeneous monogenic disease characterized by decreased bone mass, bone fragility, and recurrent fractures. The phenotypic spectrum varies considerably ranging from prenatal fractures with lethal outcomes to mild forms with few fractures and normal stature. The basic mechanism is a collagen-related defect, not only in synthesis but also in folding, processing, bone mineralization, or osteoblast function. In recent years, great progress has been made in identifying new genes and molecular mechanisms underlying OI. In this context, the classification of OI has been revised several times and different types are used. The Sillence classification, based on clinical and radiological characteristics, is currently used as a grading of clinical severity. Based on the metabolic pathway, the functional classification allows identifying regulatory elements and targeting specific therapeutic approaches. Genetic classification has the advantage of identifying the inheritance pattern, an essential element for genetic counseling and prophylaxis. Although genotype-phenotype correlations may sometimes be challenging, genetic diagnosis allows a personalized management strategy, accurate family planning, and pregnancy management decisions including options for mode of delivery, or early antenatal OI treatment. Future research on molecular pathways and pathogenic variants involved could lead to the development of genotype-based therapeutic approaches. This narrative review summarizes our current understanding of genes, molecular mechanisms involved in OI, classifications, and their utility in prophylaxis.

Case Report of Two Siblings Diagnosed with Osteogenesis Imperfecta Type XV with a New Mutation in the WNT1 Gene and Review of the Literature

Introduction

Osteogenesis imperfecta (OI) is a heritable disorder characterized by bone fractures and low bone mass. Recently, mutations of the WNT1 gene have been reported to be causative in OI. The mutation in WNT1 causes autosomal-recessive OI due to its critical role in bone formation. WNT1 mutations cause varying degrees of clinical severity, ranging from moderate to progressively deforming forms. In addition to the OI phenotype, our cases also had extra-skeletal findings.

Case Presentation

We describe two siblings with multiple fractures and developmental delay. A novel homozygous frameshift WNT1 mutation was detected in this family, and we reviewed the literature for WNT1-related OI cases.

Discussion

We report a novel variant with a clinical diagnosis of severe OI, and this review will provide a comprehensive overview of previously published cases of OI type XV. With a better understanding of disorders associated with WNT1 mutations, therapies targeting Wnt1 signaling pathway may contribute therapeutic benefits.

Mesenchymal stem cells in the treatment of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a disease caused by mutations in different genes resulting in mild, severe, or lethal forms. With no cure, researchers have investigated the use of cell therapy to correct the underlying molecular defects of OI. Mesenchymal stem cells (MSCs) are of particular interest because of their differentiation capacity, immunomodulatory effects, and their ability to migrate to sites of damage. MSCs can be isolated from different sources, expanded in culture, and have been shown to be safe in numerous clinical applications. This review summarizes the preclinical and clinical studies of MSCs in the treatment of OI. Altogether, the culmination of these studies show that MSCs from different sources: 1) are safe to use in the clinic, 2) migrate to fracture sites and growth sites in bone, 3) engraft in low levels, 4) improve clinical outcome but have a transient effect, 5) have a therapeutic effect most likely due to paracrine mechanisms, and 6) have a reduced therapeutic potential when isolated from patients with OI.

Osteoporosis in children and adolescents: how to treat and monitor?

Osteoporosis is a condition of increased bone fragility associated with fractures. Apart from primary genetic osteoporotic conditions, secondary osteoporosis in children is being increasingly recognized. As a result, there is growing interest in its prevention and treatment. Important goals of care are to prevent fractures, increase bone mass and trabecular and cortical thickness, reshape vertebral fractures, prevent (or correct) skeletal deformities, and improve mobility, independence, and quality of life. Secondary pediatric osteoporosis is often of multifactorial origin since affected children frequently have more than one acquired factor that is detrimental to bone health. Typical conditions causing osteoporosis are leukemias, progressive muscle or neurological disorders, as well as chronic inflammatory conditions and their treatment. Management of children with osteoporosis involves a multidisciplinary team involving pediatric experts from different subspecialties. With regard to prevention and early intervention, it is important to provide optimal management of any underlying systemic conditions including avoidance, or dose-reduction, of osteotoxic medications. Basic supporting life-style measures, such as appropriate nutrition, including adequate calcium intake and vitamin D, and physical activity are recommended, where possible. When pediatric treatment criteria for osteoporosis are met, antiresorptive drugs constitute the first pharmacological line treatment.

CONCLUSION

This clinical review focuses on the prevention, treatment, and follow-up of children with, or at risk of developing, osteoporosis and the transition from pediatric to adult care.

WHAT IS KNOWN

• Osteoporosis and associated fractures can cause significant morbidity and reduce the quality of life. • The developing skeleton has huge potential for recovery and reshaping, thus early detection of fractures, assessment of recovery potential, and treatment of children with osteoporosis can prevent future fractures, deformities, and scoliosis, improve function and mobility, and reduce pain.

WHAT IS NEW

• Osteoporosis in children and adolescents requires a multidisciplinary approach with a thorough assessment of recovery potential, and indication for therapy should be personalized. • Although bisphosphonates still represent the drug most commonly used to increase bone mass, improve mobility, and reduce pain and recurrence of fractures, new agents are being developed and could be beneficial in children with specific conditions.

Bisphosphonates for osteoporosis in people with cystic fibrosis

BACKGROUND

Osteoporosis is a disorder of bone mineralisation occurring in about one third of adults with cystic fibrosis. Bisphosphonates can increase bone mineral density and decrease the risk of new fractures in post-menopausal women and people receiving long-term oral corticosteroids. This is an updated version of a previous review.

OBJECTIVES

To assess the effects of bisphosphonates on the frequency of fractures, bone mineral density, quality of life, adverse events, trial withdrawals, and survival in people with cystic fibrosis.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register of references (identified from electronic database searches and hand searches of journals and abstract books) on 5 May 2022. We performed additional searches of PubMed, clinicaltrials.gov and the WHO ICTRP (International Clinical Trials Registry Platform) on 5 May 2022.

SELECTION CRITERIA

Randomised controlled trials of at least six months duration studying bisphosphonates in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Authors independently selected trials, extracted data and assessed risk of bias in included studies. Trial investigators were contacted to obtain missing data. We judged the certainty of the evidence using GRADE.

MAIN RESULTS

We included nine trials with a total of 385 participants (272 adults and 113 children (aged five to 18 years)). Trial durations ranged from six months to two years. Only two of the studies were considered to have a low risk of bias for all the domains.  Bisphosphonates compared to control in people with cystic fibrosis who have not had a lung transplant Seven trials included only adult participants without lung transplants, one trial included both adults and children without lung transplantation (total of 238 adults and 113 children). We analysed adults (n = 238) and children (n = 113) separately. Adults Three trials assessed intravenous bisphosphonates (one assessed pamidronate and two assessed zoledronate) and five trials assessed oral bisphosphonates (one assessed risedronate and four assessed alendronate). Bisphosphonates were compared to either placebo or calcium (with or without additional vitamin D). Data showed no difference between treatment or control groups in new vertebral fractures at 12 months (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.02 to 2.09; 5 trials, 142 participants; very low-certainty evidence) and two trials (44 participants) reported no vertebral fractures at 24 months. There was no difference in non-vertebral fractures at 12 months (OR 2.11, 95% CI 0.18 to 25.35; 4 trials, 95 participants; very low-certainty evidence) and again two trials (44 participants) reported no non-vertebral fractures at 24 months. There was no difference in total fractures between groups at 12 months (OR 0.57, 95% CI 0.13 to 2.50; 5 trials, 142 participants) and no fractures were reported in two trials (44 participants) at 24 months. At 12 months, bisphosphonates may increase bone mineral density at the lumbar spine (mean difference (MD) 6.31, 95% CI 5.39 to 7.22; 6 trials, 171 participants; low-certainty evidence) and at the hip or femur (MD 4.41, 95% 3.44 to 5.37; 5 trials, 155 participants; low-certainty evidence). There was no clear difference in quality of life scores at 12 months (1 trial, 47 participants; low-certainty evidence), but bisphosphonates probably led to more adverse events (bone pain) at 12 months (OR 8.49, 95% CI 3.20 to 22.56; 7 trials, 206 participants; moderate-certainty evidence). Children The single trial in 113 children compared oral alendronate to placebo. We graded all evidence as low certainty. At 12 months we found no difference between treatment and placebo in new vertebral fractures (OR 0.32, 95% CI 0.03 to 3.13; 1 trial, 113 participants) and non-vertebral fractures (OR 0.19, 95% CI 0.01 to 4.04; 1 trial, 113 participants). There was also no difference in total fractures (OR 0.18, 95% CI 0.02 to 1.61; 1 trial, 113 participants). Bisphosphonates may increase bone mineral density at the lumbar spine at 12 months (MD 14.50, 95% CI 12.91 to 16.09). There was no difference in bone or muscle pain (MD 3.00, 95% CI 0.12 to 75.22), fever (MD 3.00, 95% CI 0.12 to 75.22) or gastrointestinal adverse events (OR 0.67, 95% CI 0.20 to 2.26). The trial did not measure bone mineral density at the hip/femur or report on quality of life.  Bisphosphonates compared to control in people with cystic fibrosis who have had a lung transplant One trial of 34 adults who had undergone lung transplantation compared intravenous pamidronate to no bisphosphonate treatment. It did not report at 12 months and we report the 24-month data (not assessed by GRADE). There was no difference in the number of fractures, either vertebral or non-vertebral. However, bone mineral density increased with treatment at the lumbar spine (MD 6.20, 95% CI 4.28 to 8.12) and femur (MD 7.90, 95% CI 5.78 to 10.02). No participants in either group reported either bone pain or fever. The trial did not measure quality of life.

AUTHORS' CONCLUSIONS

Oral and intravenous bisphosphonates may increase bone mineral density in people with cystic fibrosis, but there are insufficient data to determine whether treatment reduces fractures. Severe bone pain and flu-like symptoms may occur with intravenous bisphosphonates. Before any firm conclusions can be drawn, trials in larger populations, including children, and of longer duration are needed to determine effects on fracture rate and survival. Additional trials are needed to determine if bone pain is more common or severe (or both) with the more potent zoledronate and if corticosteroids can ameliorate or prevent these adverse events. Future trials should also assess gastrointestinal adverse effects associated with oral bisphosphonates.

A multicenter study to evaluate pain characteristics in osteogenesis imperfecta

The objective was to describe pain characteristics and treatments used in individuals with varying severity of osteogenesis imperfecta (OI) and investigate pain-associated variables. This work was derived from a multicenter, longitudinal, observational, natural history study of OI conducted at 12 clinical sites of the NIH Rare Diseases Clinical Research Network's Brittle Bone Disorders Consortium. Children and adults with a clinical, biochemical, or molecular diagnosis of OI were enrolled in the study. We did a cross-sectional analysis of chronic pain prevalence, characteristics, and treatments used for pain relief and longitudinal analysis to find the predictors of chronic pain. We included 861 individuals with OI, in 41.8% chronic pain was present, with similar frequency across OI types. Back pain was the most frequent location. Nonsteroidal anti-inflammatory drugs followed by bisphosphonates were the most common treatment used. Participants with chronic pain missed more days from school or work/year and performed worse in all mobility metrics than participants without chronic pain. The variables more significantly associated with chronic pain were age, sex, positive history of rodding surgery, scoliosis, other medical problems, assistive devices, lower standardized height, and higher body mass index. The predictors of chronic pain for all OI types were age, use of a wheelchair, and the number of fractures/year. Chronic pain is prevalent in OI across all OI types, affects mobility, and interferes with participation. Multiple covariates were associated with chronic pain.

[Features and results of surgical rehabilitation of hearing loss in osteogenesis imperfecta]

Osteogenesis imperfecta (OI) is a form of congenital osteoporosis. Depending on the type of OI, patients experience various types of hearing loss. Depending on the type and degree of hearing loss, various methods of hearing rehabilitation are used in this category of patients.

OBJECTIVE

To evaluate the features and results of surgical rehabilitation of hearing loss in patients with osteogenesis imperfecta.

MATERIAL AND METHODS

During the period from 2009 to 2022, 2221 primary stapedoplasty was performed in the department, of which 23 (1.04%) in 21 patients were performed in patients with OI. There were 14 women and 7 men. According to TPA, bilateral hearing loss was detected in 19 patients and unilateral in 2. Conductive hearing loss was observed in 9 cases and mixed - in 14. The average thresholds for bone conduction (BC) were 22.7±8.04 dB, and the bone-air interval (ABG) - 36.1±5.3 dB. According to CT of the temporal bones, all patients showed a bilateral and symmetrical decrease in the density of the auditory ossicles, and in 7 patients there were extensive areas of non-uniform decrease in the density of the bone labyrinth up to +500 - +1000 HU.21 patients underwent 23 operations: in 21 cases stapedoplasty with laser assistance and in 2 cases ossiculoplasty.

RESULTS

BC thresholds 6 months after surgery averaged 24.6±8.2 dB, and ABG - 12.1±2.9 dB. Closing of ABG ≤10 dB at spoken frequencies was detected in 30.5%, ABG ≤20 dB - in 95%. After 12 months or more after the operation, no change in the audiological parameters was noted.

CONCLUSIONS

Stapes surgery for conductive and mixed hearing loss in OI patients is functionally effective. The best results are achieved after therapy with bisphosphonates with preparations of sodium fluoride, calcium and vitamin D, performing the operation when the density of demineralization zones reaches 1000 HU and using laser assistance. Taking into account the demineralization of the bone structures of the temporal bone, it is recommended to use autocartilaginous stirrup prostheses to restore sound conduction or to cover the attachment area of other prostheses with autologous tissues to prevent necrosis of the long stalk of the incus and stabilize long-term functional results.

Treatment Practices and Confidence in the Management of Pediatric Metabolic Bone Disorders

INTRODUCTION

Pediatric metabolic bone and mineral disorders encompass a wide variety of disorders that can be challenging to diagnose and treat because of inadequate physician training about optimal management.

METHODS

As practice variation and confidence levels may impact clinical outcome, we sought to assess physician confidence in managing pediatric metabolic bone and mineral disorders and the spectrum of treatment practices among members of the Pediatric Endocrine Society (PES) and the Canadian Pediatric Endocrine Group (CPEG). Questionnaires were distributed via e-mail to all members of the PES and CPEG and 244 were completed. Responses were summarized using descriptive statistics, and proportions were compared using χ2 or Fisher's exact tests, as appropriate.

RESULTS

Variations were observed among the respondents' confidence in the management of bone disorders and in the criteria used to initiate/discontinue intravenous bisphosphonates or prescribe burosumab therapy. Respondents felt confident with the management of 4 out of 20 pediatric bone conditions (confidence was defined as >90% of respondents reporting feeling "somewhat confident" or "very confident"). Physicians working in a bone clinic were more confident in prescribing burosumab for the treatment of X-linked hypophosphatemic rickets compared to those not working in a bone clinic (65% vs. 47%, p = 0.03). Most respondents (52%) reported having received inadequate training in pediatric metabolic bone and mineral disorders.

DISCUSSION/CONCLUSION

Dedicated training, knowledge acquisition, and education resources are needed to increase confidence and standardize the use of bone-targeted therapies.

Does the c.-14C>T Mutation in the IFITM5 Gene Provide Identical Phenotypes for Osteogenesis Imperfecta Type V? Data from Russia and a Literature Review

Osteogenesis imperfecta (OI) is a large group of genetically heterogeneous diseases resulting from decreased bone density and an abnormal microarchitecture, which are clinically manifested by abnormal bone fractures. A distinctive clinical feature of this group of diseases is the presence of spontaneous fractures and skeletal deformities. However, the clinical manifestations of different types of OI are characterized by marked polymorphism with variable severity of skeletal and extra-skeletal features. Previous studies have shown that a mutation (c.-14C>T) in the IFITM5 gene is responsible for autosomal dominant OI type V. However, the mutation has a variable expression pattern and marked clinical heterogeneity. In this study, a clinical and genetic analysis of 12 cases with molecularly confirmed OI type V from 12 unrelated families was performed. Significant clinical heterogeneity of the disease with the same molecular defect was detected. In six subjects (50%), there were no classic signs of OI type V (formation of a hyperplastic bone callus, calcification of the interosseous membrane and dislocation of the radial head). In all cases, the mutation occurred de novo.

Exploring pain interference and self-perceived health status in children with osteogenesis imperfecta - a cross-sectional study

Background

Chronic pain may affect and interfere in children’s everyday life and can be present in children with Osteogenesis Imperfecta (OI). However, the knowledge is still sparse to what extent pain is present, how pain interfere in children’s everyday life and affect their self-perceived health status. The purpose of the study was therefore to explore presence of chronic pain, pain interference in daily life, and self-perceived health status in children with OI.

Methods

Children with OI, aged 6–18 years, were recruited consecutively to this cross-sectional study. Participants answered a standardised interview including five pre-structured questions, and the Numeric Pain Rating Scale (NPRS), the Pain Interference Index, and a questionnaire concerning self-perceived health status the Patient Reported Outcomes Measurement Information System Pediatric-25 Profile v1.1 (PROMIS-25).

Results

Twenty-eight children (median: 11 years, IQR 6) with OI type I, III, or IV participated. Pain was present in 27 of 28 children and interfered in their everyday life regardless of OI-type, sex, and age. The median NPRS for average pain intensity was 4 (IQR 2), the median for pain frequency was 2–3 times/week, and the median frequency of school absence due to pain was 2–3 times per month. The most common pain locations were back and feet. Pain in the feet was more frequently reported in children with type I (p = 0.032), and pain in the hip was more often reported in children ≥13 years (p = 0.011). The children were asked what they thought to be the cause of pain and the most frequent response was “walking long distances”. Self-perceived health status for mobility was lower than the general population, and lowest for children with type III (p = 0.016). Pain interference was associated with children’s self-perceived health status (r_s = 0.84, p < 0.001).

Conclusion

Almost all children experienced pain, which interfered in children’s everyday lives, affected participation in various activities and was associated with reduced self-perceived health status. If children avoid physical activities because of pain, it might cause a vicious circle of inactivity, which further decreases bone density and increase the risk of fractures. The results emphasize the importance to offer adequate pain reducing interventions.

Biomechanical, Microstructural and Material Properties of Tendon and Bone in the Young Oim Mice Model of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by low bone mass and spontaneous fractures, as well as extra-skeletal manifestations, such as dental abnormalities, blue sclera, hearing loss and joint hypermobility. Tendon ruptures have been reported in OI patients. Here, we characterized the biomechanical, structural and tissue material properties of bone and tendon in 5-week-old female osteogenesis imperfecta mice (oim), a validated model of severe type III OI, and compared these data with age- and sex-matched WT littermates. Oim tendons were less rigid and less resistant than those of WT mice. They also presented a significantly higher rate of pentosidine, without significant modification of enzymatic crosslinking. The oim bones were less resistant and avulsion fractures were evident at high tendinous stress areas. Alterations of trabecular and cortical bone microarchitectures were noticed in young female oim. Bone tissue material properties were also modified, with a less mature and more mineralized matrix in association with lower collagen maturity. Our data suggest that the tendon-to-bone unit is affected in young oim mice, which could explain tendon ruptures and bone fragility observed in OI patients.

Functional Independence of Taiwanese Children with Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a group of rare genetic disorders that affect bone formation. Patients with OI present mainly with increased bone fragility and bone deformities. Twenty-seven Taiwanese children between 2 and 21 years of age with OI and their parents were recruited at MacKay Memorial Hospital from January 2013 to December 2019. We used the Functional Independence Measure for Children (WeeFIM) questionnaire to assess the functional independence of the children and describe any functional limitations or additional burden of daily care. Out of a potential score of 126, the mean total WeeFIM score was 113.7. There was a statistically significant difference between the scores of type I, type III and type IV OI (121.88 [SD 7.01] vs. 80.8 [SD 26.25] vs. 119.17 [SD 10.89]; p < 0.001). There were no statistically significant differences between the scores in different age groups, the male and female participants, and patients with pathogenic variants in COL1A1 and COL1A2. The mean scores for the self-care, mobility, and cognition domains were 48.78 (maximum 56, mean quotient 91.14%), 30.44 (maximum 35, mean quotient 87.12%), and 34.44 (maximum 35, mean quotient 99.05%), respectively. The best performance was in the cognition domain (mean quotient 99.05%), and the worst was in the mobility domain (mean quotient 87.12%). There were no statistically significant correlations between WeeFIM scores and age, or age when symptoms began. The total WeeFIM score and 13 subscores for the self-care and mobility domains were all positively correlated with body height (p < 0.01). The correlation was lowest for bowel and walking/wheelchair tasks, and the highest for bathing and dressing-upper tasks. For tasks in bathing, over 40% of the patients needed help. For tasks in the cognition domain, most patients required no help. For the Taiwanese children with OI, some support and supervision were required for self-care and mobility tasks, and the functional independence in these two domains was correlated with body height and disease types. The WeeFIM questionnaire may be a useful tool to assess the functional strengths and weaknesses of children with OI.

Osteogenesis Imperfecta: Multidisciplinary and Goal-Centered Care

We describe a case of osteogenesis imperfecta (OI) in a late preterm female of 35-week gestation. The mother did have a history of substance abuse, poor prenatal care, and hypertension. On the day of delivery, an ultrasound revealed skeletal dysplasia and breech with nonreassuring fetal tracing, leading to an emergency cesarean. The clinical exam was concerning for OI, and postnatal care was focused on optimizing respiratory status and minimizing pain and discomfort during routine care. Genetics, endocrine, orthopaedics, and palliative care were all involved to diagnose and educate the family. Support and education were needed for bedside staff to minimize angst at performing routine care, given the high risk of fractures. While initially stable on minimal oxygen, once the diagnosis of type III OI was made, a progressively deforming condition with respiratory status decompensation, the family wished to minimize suffering, limited aggressive medical care, and focused on comfort. The infant eventually died from respiratory failure in the neonatal intensive care unit. We present this case to demonstrate the need for an interdisciplinary team approach to support both family and staff in cases of OI.

Secondary Osteoporosis and Metabolic Bone Diseases

Fragility fracture is a worldwide problem and a main cause of disability and impaired quality of life. It is primarily caused by osteoporosis, characterized by impaired bone quantity and or quality. Proper diagnosis of osteoporosis is essential for prevention of fragility fractures. Osteoporosis can be primary in postmenopausal women because of estrogen deficiency. Secondary forms of osteoporosis are not uncommon in both men and women. Most systemic illnesses and organ dysfunction can lead to osteoporosis. The kidney plays a crucial role in maintaining physiological bone homeostasis by controlling minerals, electrolytes, acid-base, vitamin D and parathyroid function. Chronic kidney disease with its uremic milieu disturbs this balance, leading to renal osteodystrophy. Diabetes mellitus represents the most common secondary cause of osteoporosis. Thyroid and parathyroid disorders can dysregulate the osteoblast/osteoclast functions. Gastrointestinal disorders, malnutrition and malabsorption can result in mineral and vitamin D deficiencies and bone loss. Patients with chronic liver disease have a higher risk of fracture due to hepatic osteodystrophy. Proinflammatory cytokines in infectious, autoimmune, and hematological disorders can stimulate osteoclastogenesis, leading to osteoporosis. Moreover, drug-induced osteoporosis is not uncommon. In this review, we focus on causes, pathogenesis, and management of secondary osteoporosis.

Clinical practice guidelines for optimizing bone health in Korean children and adolescents

The Committee on Pediatric Bone Health of the Korean Society of Pediatric Endocrinology has newly developed evidence-based clinical practice guidelines for optimizing bone health in Korean children and adolescents. These guidelines present recommendations based on the Grading of Recommendations, which includes the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion. These guidelines include processes of bone acquisition, definition, and evaluation of low bone mineral density (BMD), causes of osteoporosis, methods for optimizing bone health, and pharmacological treatments for enhancing BMD in children and adolescents. While these guidelines provide current evidence-based recommendations, further research is required to strengthen these guidelines.

Drug Treatment of Low Bone Mass and Other Bone Conditions in Pediatric Patients

Osteoporosis may affect young individuals, albeit infrequently. In childhood, bone mass increases, reaching its peak between the second and third decades; then, after a period of stability, it gradually declines. Several conditions, including genetic disorders, chronic diseases, and some medications, can have an impact on bone homeostasis. Diagnosis in young patients is based on the criteria defined by the International Society for Clinical Densitometry (ISCD), published in 2013. High risk factors should be identified and monitored. Often simple interventions aimed to eliminate the underlying cause, to minimize the negative bone effects linked to drugs, or to increase calcium and vitamin D intake can protect bone mass. However, in selected cases, pharmacological treatment should be considered. Bisphosphonates remain the main therapeutic agent for children with significant skeletal fragility and are also useful in a large number of other bone conditions. Denosumab, an anti-RANKL antibody, could become a potential alternative treatment. Clinical trials to evaluate the long-term effects and safety of denosumab in children are ongoing.

Pamidronate Therapy Increases Trabecular Bone Complexity of Mandibular Condyles in Individuals with Osteogenesis Imperfecta

Patients with Osteogenesis Imperfecta (OI) present extra-skeletal manifestations, including important orodental and craniofacial features as dentinogenesis imperfecta, dental agenesis, failure of maxilla growth and hypotonia of masticatory muscles. These features may compromise vital functions speech and mastication. Studies have demonstrated that cyclic pamidronate infusion, the standard therapy for patients with moderate to severe OI, influences the histomorphometric pattern of different body bones. The present study aimed to investigate the condyle trabecular bone pattern in OI patients. We used fractal dimension (FD) analysis on dental panoramic radiographic images to characterize the mandibular condyle trabecular bone in adolescents diagnosed with OI and treated with pamidronate. Imaging exam of 33 adolescents of both sexes, aged between 12 and 17 years, were analyzed and compared with 99 age- and sex-matched healthy adolescents. FD in patients was significantly lower (1.23 ± 0.15) than in healthy controls (1.29 ± 0.11; p < 0.01). Type of OI, age at treatment onset, and the duration of therapy were variables that showed a statistically significant effect on the FD results. This study demonstrated that the bone architecture of mandibular condyles may be altered in pediatric patients with moderate and severe forms of OI. Also, pamidronate treatment seems to have a positive effect on condyle trabecular bone in these patients. This is supported by our finding that FD values were positively influenced by the length of cyclic pamidronate treatment at the time of imaging, as well as by the age of the individual at treatment onset.

Dental Implants in People with Osteogenesis Imperfecta: A Systematic Review

The aim of this systematic review was to answer the question of whether patients with osteogenesis imperfecta can be prosthetically rehabilitated with dental implants. A protocol was prospectively registered in PROSPERO (CRD42021286368). The inclusion criteria were the presence of osteogenesis imperfecta and the use of implants for prosthetic restorations. Cases in which the inclusion criteria were not met were excluded. PubMed, Web of Science, and Scopus were last searched on 22 August 2021. Quality assessment was performed using the Methodological Quality and Synthesis of Case Series and Case Reports tool. The primary outcome was implant survival. Supporting data were analyzed descriptively. Twelve studies were included. Twenty-three patients received a total number of 116 implants, with 5.0 (±3.8) implants placed per patient. The implant survival rate was 94.0% with a mean follow-up of 59.1 months (±36.1). A limitation of this review was the relatively short follow-up time in some of the included studies; therefore, the survival rate may be overestimated. Nevertheless, the available data showed the loss of only seven implants, with two implants lost due to implant fractures not attributable to the patient. With the limitations of this review and based on the available data, dental implants have a high survival rate in patients with osteogenesis imperfecta. Therefore, dental implants may be a viable treatment option for replacing missing teeth. This research was not funded by external resources.

Skeletal outcomes of patients with osteogenesis imperfecta during drug holiday of bisphosphonates: a real-world study

PURPOSE

This study aimed to investigate the skeletal outcomes of patients with osteogenesis imperfecta (OI) who received bisphosphonate (BP) treatment and entered drug holiday after achieving an age- and sex-specific bone mineral density (BMD) reference.

METHODS

Patients with OI receiving BP treatment were enrolled when they entered drug holidays of BPs. The skeletal outcomes were evaluated in detail during the drug holiday, including BMD, X-ray of the bone, bone fracture incidence, and bone turnover biomarkers. The pathogenic mutations of OI were identified by next-generation sequencing and confirmed by Sanger sequencing.

RESULTS

A total of 149 OI patients (127 juveniles and 22 adults) who entered drug holidays after nearly 4 years of BP treatment were included. Areal BMD at the lumbar spine increased from 0.934 ± 0.151 to 0.990 ± 0.142 g/cm² and was stable in the second (1.029 ± 0.176 g/cm²) and third years (1.023 ± 0.174 g/cm²) of BP drug holidays, and BMD at the femoral neck, trochanter, and total hip had no significant change, but it was gradually inferior to that of the same-gender juveniles in the second and third years of the drug holiday. BMD at the lumbar spine and proximal hip did not change and was inferior to that of the same-gender adults. The average time of fractures fluctuated from 0.18 to 0.08 per year in juveniles, while only one adult suffered from a fracture during BP drug holidays. Bone turnover markers were in the normal range, except for a mildly high level of β-carboxy-terminal cross-linked telopeptide of type 1 collagen in the juvenile group. A total of 17 (11.4%) patients received BP retreatment because of bone loss during the drug holiday. OI type III and type IV and COL1A2 mutation were correlated to a longer duration of BP treatment to enter drug holidays (all p < 0.05). Old age at initial treatment (OR, 1.056) and OI type III (OR, 10.880) were correlated to a higher risk of BP retreatment.

CONCLUSIONS

OI patients will undergo nearly 4 years of BP treatment to achieve drug holidays. During the 3 years of the drug holiday, the patients' BMD is stable, and fracture incidence does not increase significantly. Patients are more inclined to need retreatment during drug holidays owing to the late start of BP treatment and more severe OI phenotypes.

Fractures following pregnancy in Osteogenesis imperfecta - A self-controlled case series using Danish Health Registers

Osteogenesis imperfecta (OI) is a rare inherited connective tissue disorder with considerable clinical and genetic heterogeneity. The clinical hallmark of OI is liability to fractures due to reduced bone strength. Pregnancy and lactation are periods of increased calcium demand resulting in a decrease in maternal bone mineral density (BMD). This self-controlled case series evaluates fracture risk 12- and 19-months prior to conception compared to a period of 12- and 19 months following childbirth in women with OI. This study is based on data from the Danish National Patient Register collected between 1995 and 2018. Modified Poisson models were fitted to estimate Incidence Rate Ratio in the post/pre-pregnancy period/s, adjusted by parity and age. The 12-month observation group included 111 women with 205 pregnancies, and the 19-month observation 108 women with 197 pregnancies. We calculated fracture rates (IR) of 48.78 [95%CI 18.55-79.01] per 1000 person years 12 months prior to conception, and of 27.87 [95%CI 10.60-45.14] in the 12 months post-delivery. Comparing pre- and post-pregnancy period we found an incidence rate ratio (IRR) of 1.00 [95%CI 0.42-2.40]. When adjusting for parity and age at delivery no significant change in the IRR was noted. In the 19 months observation-period, the IR per 1000 person years prior to conception was 74.84 [95%CI 44.25-105.43] and the IR postpartum was 36.86 [95%CI 17.55-56.17], leading to an IRR of 0.61 [95%CI 0.31-1.18]. We could not identify any increased risk of fractures when comparing fracture rates during pregnancy and 12 or 19 months postpartum to fracture rates 12 or 19 months prior to conception.

A systematic review and meta-analysis on the efficacy of stem cell therapy on bone brittleness in mouse models of osteogenesis imperfecta

There is no cure for osteogenesis imperfecta (OI), and current treatments can only partially correct the bone phenotype. Stem cell therapy holds potential to improve bone quality and quantity in OI. Here, we conduct a systematic review and meta-analysis of published studies to investigate the efficacy of stem cell therapy to rescue bone brittleness in mouse models of OI. Identified studies included bone marrow, mesenchymal stem cells, and human fetal stem cells. Effect size of fracture incidence, maximum load, stiffness, cortical thickness, bone volume fraction, and raw engraftment rates were pooled in a random-effects meta-analysis. Cell type, cell number, injection route, mouse age, irradiation, anatomical bone, and follow up time were considered as moderators. It was not possible to investigate further parameters due to the lack of standards of investigation between the studies. Despite the use of oim mice in the majority of the investigations considered and the lack of sham mice as control, this study demonstrates the promising potential of stem cell therapy to reduce fractures in OI. Although their low engraftment, cell therapy in mouse models of OI had a beneficial effect on maximum load, but not on stiffness, cortical thickness and bone volume. These parameters all depend on bone geometry and do not inform on its material properties. Being bone fractures the primary symptom of OI, there is a critical need to measure the fracture toughness of OI bone treated with stem cells to assess the actual efficacy of the treatment to rescue OI bone brittleness.

X-Linked Osteogenesis Imperfecta Possibly Caused by a Novel Variant in PLS3

Osteogenesis imperfecta (OI) represents a complex spectrum of genetic bone diseases that occur primarily due to mutations and deletions of the COL1A1 and COL1A2 genes. Recent molecular studies of the network of signaling pathways have contributed to a better understanding of bone remodeling and the pathogenesis of OI caused by mutations in many other genes associated with normal bone mineralization. In this paper, a case of a rare X-linked variant of OI with a change in the gene encoding plastin 3—a protein important for the regulation of the actin cytoskeleton, is presented. A 16-year-old patient developed ten bone fractures caused by minor trauma or injury, including a compression fracture of the second lumbar vertebra during his lifetime. Next-generation sequencing analysis did not show pathologically relevant deviations in the COL1A1 and COL1A2 genes. Targeted gene analyses (Skeletal disorder panel) of the patient, his father, mother and sister were then performed, detecting variants of uncertain significance (VUS) for genes PLS3, FN1 and COL11A2. A variant in the PLS3 gene were identified in the patient, his mother and sister. Since the PLS3 gene is located on the X chromosome, the mother and sister showed no signs of the disease. Although the variant in the PLS3 gene (c.685G>A (p.Gly229Arg)) has not yet been described in the literature, nor is its pathogenicity known, clinical findings combined with genetic testing showed that this variant may explain the cause of X-linked OI in our patient. This rare case of the PLS3 variant of X-linked OI might point to a novel target for personalized therapy in patients with this severe disease.

Denosumab for the treatment of primary pediatric osteoporosis

Primary osteoporosis is rare in children and adolescents and its optimal pharmacological management is uncertain. Bisphosphonates are commonly used while denosumab has only been administered to a few children with osteogenesis imperfecta. We studied a treatment-naïve 13.5-year-old boy with severe osteoporosis and multiple vertebral deformities who presented with back pain and difficulty in walking. Causes of secondary osteoporosis were excluded and there were no abnormalities in genes known to cause bone fragility. He was treated with denosumab 60 mg subcutaneously every 3 months for 30 months, and he was pain-free within 6 weeks after the first injection. Lumbar spine BMD and femoral neck BMD increased with treatment by 65.6% and 25.3%, respectively, and deformed vertebrae regained their normal shape; linear growth was not impaired. During the second year of treatment, transient hypercalcemia (maximum 3.09 mmol/l) before the denosumab injection was observed. In conclusion, denosumab was highly effective in this case of primary pediatric osteoporosis, with remarkable clinical and radiological response. Transient hypercalcemia was probably due to amplification of the effect of growth spurt and puberty on bone remodeling by the transient, short-term discontinuation of the drug. Furthermore, our data suggest that mobilization of calcium from treatment-induced sclerotic transverse lines in bone metaphyses may contribute to the development of hypercalcemia.

Diagnostic utility of next-generation sequencing-based panel testing in 543 patients with suspected skeletal dysplasia

Background

Skeletal dysplasia is typically diagnosed using a combination of radiographic imaging, clinical examinations, and molecular testing. Identifying a molecular diagnosis for an individual with a skeletal dysplasia can lead to improved clinical care, guide future medical management and treatment, and inform assessment of risk for familial recurrence. The molecular diagnostic utility of multi-gene panel testing using next-generation sequencing (NGS) has not yet been characterized for an unselected population of individuals with suspected skeletal dysplasia. In this study, we retrospectively reviewed patient reports to assess the diagnostic yield, reported variant characteristics, impact of copy number variation, and performance in prenatal diagnostics of panel tests for variants in genes associated with skeletal dysplasia and growth disorders.

Results

Clinical reports of consecutive patients with a clinical indication of suspected skeletal dysplasia who underwent panel testing were examined. The 543 patients included in the study submitted samples for diagnostic genetic testing with an indication of suspected skeletal dysplasia or growth disorder and received one of three nested panel tests. A molecular diagnosis was established in 42.0% of patients (n = 228/543). Diagnostic variants were identified in 71 genes, nearly half of which (n = 35, 49.3%) contributed uniquely to a molecular diagnosis for a single patient in this cohort. Diagnostic yield was significantly higher among fetal samples (59.0%, n = 52/88) than postnatal samples (38.7%, n = 176/455; z = 3.55, p < 0.001). Diagnostic variants in fetal cases were identified across 18 genes. Thirteen diagnostic CNVs were reported, representing 5.7% of diagnostic findings and ranging in size from 241-bp to whole chromosome aneuploidy. Additionally, 11.4% (36/315) of non-diagnostic patient reports had suspicious variants of unknown significance (VUS), in which additional family studies that provide segregation data and/or functional characterization may result in reclassification to likely pathogenic.

Conclusions

These findings demonstrate the utility of panel testing for individuals with a suspected skeletal dysplasia or growth disorder, with a particularly high diagnostic yield seen in prenatal cases. Pursuing comprehensive panel testing with high-resolution CNV analysis can provide a diagnostic benefit, given the considerable phenotype overlap amongst skeletal dysplasia conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02025-7.

High Bone Mineral Density Osteogenesis Imperfecta in a Family with a Novel Pathogenic Variant in COL1A2

Osteogenesis imperfecta (OI) is a heterogenous group of heritable bone dysplasias characterized by bone fragility, typically low bone mass, joint laxity, easy bruising, and variable short stature. Classical OI is caused by autosomal dominant pathogenic variants in COL1A1 or COL1A2 that result in either reduced production of normal type 1 collagen or structurally abnormal collagen molecules. Pathogenic variants in these genes generally result in low bone mass. Here, we report a family that had 2 affected individuals who presented with minimal trauma fractures and were found to have elevated bone mineral density (BMD) and a previously unreported variant in COL1A2 c.3356C>T p.(Ala1119Val). We report the change in BMD using dual-energy X-ray and peripheral quantitative computed tomography over a 2.3-year period in the proband. This case report highlights the importance of BMD studies and genetic testing in the diagnostic process for brittle bone disorders.

Abnormalities in Tooth Formation after Early Bisphosphonate Treatment in Children with Osteogenesis Imperfecta

Treatment with intravenous bisphosphonate (BP) in children and adolescents with osteogenesis imperfecta (OI) started in Sweden in 1991. No human studies on the role of BP therapy in development of disturbances in tooth mineralization or tooth morphology have been published. The study cohort comprised 219 individuals who were divided into four groups: group 1, BP treatment onset before 2 years of age (n = 22); group 2, BP treatment onset between 2 and 6 years of age (n = 20); group 3, BP treatment onset between 6 and 10 years of age (n = 13); and a control group of patients with OI who had not received BP therapy (n = 164). The chi-square test was used in between-group comparisons of the prevalence of tooth agenesis. The prevalence of tooth agenesis was significantly higher in children who began BP treatment before the age of 2 years (group 1; 59%,) compared to the controls (10%; p < 0.001) and to children who had begun BP therapy between ages 2 and 6 years (group 2; 10%; p = 0.009) or between ages 6 and 10 years (group 3; 8%; p = 0.003). Different types of disturbances in the enamel formation were seen in 52 premolars, where 51 were seen in those who began BP treatment before the age of 2 years. To conclude, starting BP treatment before the age of 2 years increases the risk of abnormalities in tooth formation manifesting as morphological aberrations, tooth agenesis, and enamel defects.

Surgical Treatment of a Bilateral Mandibular Fracture in a Patient with Osteogenesis Imperfecta Type III

Osteogenesis imperfecta is a group of genetic disorders affecting skeletal and connective tissue that commonly presents with a history of multiple fractures. In particular, Osteogenesis imperfecta type III is associated with severe bone deformities, specifically in the mandible with deformities such as mandibular overjet and cross-bite. We report a case of a bilateral mandibular fracture in a young adult diagnosed with Osteogenesis imperfecta type III, managed surgically with open reduction internal fixation.

Hospital admissions of patients with osteogenesis imperfecta in the English NHS

Hospital use by patients with osteogenesis imperfecta was largely unknown. This study found that the English NHS provides a significant number of hospital admissions to these patients, translating into large costs to the NHS. Admissions and costs both increased over time. Children under 14 years old accounted for more of the admissions and costs than any other age group.

INTRODUCTION

The aim of this study was to characterise hospital use by patients with osteogenesis imperfecta (OI) in the English National Health Service (NHS).

METHODS

Routinely collected aggregate data about all inpatient hospital records from patients with OI were used for the period 1 April 2014 to 31 March 2018. Information was extracted on number of admissions, number of patients, length of stay, and costs. Hospital use was summarised using descriptive statistics, categorising patients into 5-year age groups.

RESULTS

There were 16,245 hospital admissions for OI patients during the analysis period, with a total cost to the NHS of £24,052,451. Of the 4370 patients involved, 2700 (62%) were female. Female patients averaged 3.3 admissions per year and male patients 4.4 admissions per year. Patients aged 0 to 14 years old accounted for 54% of all admissions. Those aged 90 to 94 years had the longest average length of stay per admission (10.5 days) of any age group. Elective admissions cost on average £1260 and non-elective admissions £2529. Over the 4-year study period, number of admissions increased on average by 2.1% per year and number of patients by 6.4% per year.

CONCLUSION

The treatment of patients with OI is associated with a significant number of hospital admissions at an important cost for the NHS, with both number of admissions and costs increasing over time. Children below the age of 14 years had more admissions at a greater total cost than other ages, while the oldest adults had longer average stays and higher costs per admission.

Impact of Intrinsic Muscle Weakness on Muscle-Bone Crosstalk in Osteogenesis Imperfecta

Bone and muscle are highly synergistic tissues that communicate extensively via mechanotransduction and biochemical signaling. Osteogenesis imperfecta (OI) is a heritable connective tissue disorder of severe bone fragility and recently recognized skeletal muscle weakness. The presence of impaired bone and muscle in OI leads to a continuous cycle of altered muscle-bone crosstalk with weak muscles further compromising bone and vice versa. Currently, there is no cure for OI and understanding the pathogenesis of the skeletal muscle weakness in relation to the bone pathogenesis of OI in light of the critical role of muscle-bone crosstalk is essential to developing and identifying novel therapeutic targets and strategies for OI. This review will highlight how impaired skeletal muscle function contributes to the pathophysiology of OI and how this phenomenon further perpetuates bone fragility.

Functional outcomes of an adult with osteogenesis imperfecta after rehabilitation post bilateral Girdlestone procedure

This is a case of a 54-year-old woman managed as a case of osteogenesis imperfecta type 1 who sustained a left subtrochanteric fracture and eventual ankylosis of both hips after surgery and immobilisation. These injuries rendered her bedridden, maximally assisted in transitions and transfers, and unable to be positioned past 30° of backrest elevation. The patient underwent a bilateral Girdlestone procedure and had tailored progressive postoperative rehabilitation in both the inpatient and outpatient settings. The patient also continued to receive bisphosphonates during her preoperative and postoperative period, to improve bone stock and aid in relieving pain. Through the efforts of a team of physiatrists, geneticists and orthopaedic surgeons, the patient was able to achieve pain-free sitting, independent transitions and short-distance ambulation, which have allowed her to care for herself more effectively and return to her work and activities of daily living.

Survey of MRI Usefulness for the Clinical Assessment of Bone Microstructure

Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patients’ risk stratification and therapy delivery. Magnetic resonance imaging (MRI) has been proposed as another technique to assess bone quality and fracture risk by evaluating the bone structure and microarchitecture. To date, MRI is the only completely non-invasive and non-ionizing imaging modality that can assess both cortical and trabecular bone in vivo. In this review article, we reported a survey regarding the clinically relevant information MRI could provide for the assessment of the inner trabecular morphology of different bone segments. The last section will be devoted to the upcoming MRI applications (MR spectroscopy and chemical shift encoding MRI, solid state MRI and quantitative susceptibility mapping), which could provide additional biomarkers for the assessment of bone microarchitecture.

[Rehabilitation of orphan diseases in adulthood: osteogenesis imperfecta]

Osteogenesis imperfecta (brittle bone disease) is an orphan disease caused by a genetic mutation in collagen metabolism. Bone fractures are the most common symptoms; however, the clinical manifestation can vary widely. Additional features can include blue sclera, dwarfism, bone deformities, muscular weakness, scoliosis, hearing loss and hypermobility of joints. Most patients show a reduction of skeletal function. This leads to an increased risk of being unable to continue their former work and to participate in social life. A comprehensive treatment includes drug therapy, surgery and rehabilitation. This article gives an overview of the current status of rehabilitation in adult patients with osteogenesis imperfecta.

Bone density, fractures and the associated factors in iranian children and adolescent with Osteogenesis Imperfecta

Backround

Osteogenesis imperfecta(OI) is a frequent bone fragility disorder in children. The purpose of this study was to assess the BMD and Vitamin D level in children with OI in southern Iran.

Method

This case-control study was conducted on 23 children, clinically diagnosed as osteogenesis imperfecta and 23 age- and gender-matched healthy controls. Demographic and anthropometric data, biochemical parameters, puberty, sun exposure and physical activity were assessed. Bone mineral density (BMD) was measured by Dual-energy X-ray absorptiometry (DXA). Data analysis was done by SPSS22.

Results

Forty-three point four percent of OI patients and fifty-six point five percent of control group had vitamin D deficiency (P = 0.376). Thirteen OI patients (56%) had low bone mass for chronological age in lumbar area (P < 0.001). Fracture episodes during treatment was significantly influenced by time of Pamidronate start, courses of Pamidronate injection, puberty and sun exposure (P values = 0.015, 0.030, 0.044 and 0.032, respectively). Fracture episodes during treatment had significantly increased in patients who had received Pamidronate more than 3 years compared with those received less than 3 years(P values = 0.047).

Conclusions

This study showed that vitamin D deficiency is prevalent amongst OI children in southern Iran. More than half of the OI children had low bone mass for chronological age in lumbar area, despite receiving bisphosphonate therapy. The present results revealed that early initiation of Pamidronate and number of Pamidronate courses are associated with lower fracture rate. However, treatment period more than 3 years can have adverse effect on fracture rates.

Mechanisms of Bone Fragility: From Osteogenesis Imperfecta to Secondary Osteoporosis

Bone material strength is determined by several factors, such as bone mass, matrix composition, mineralization, architecture and shape. From a clinical perspective, bone fragility is classified as primary (i.e., genetic and rare) or secondary (i.e., acquired and common) osteoporosis. Understanding the mechanism of rare genetic bone fragility disorders not only advances medical knowledge on rare diseases, it may open doors for drug development for more common disorders (i.e., postmenopausal osteoporosis). In this review, we highlight the main disease mechanisms underlying the development of human bone fragility associated with low bone mass known to date. The pathways we focus on are type I collagen processing, WNT-signaling, TGF-ß signaling, the RANKL-RANK system and the osteocyte mechanosensing pathway. We demonstrate how the discovery of most of these pathways has led to targeted, pathway-specific treatments.

Osteogenesis Imperfecta in neonatal period in Cameroon: A case report

Early forms of Osteogenesis Imperfecta should be considered as main etiology of bone deformities in newborns. Prenatal diagnosis and genetic counseling should be improved in Africa. Management of these children remains difficult in low-income countries.