Camurati-Engelmann disease: review of the clinical, radiological, and molecular data of 24 families and implications for diagnosis and treatment

Heterozygous mutations in the straitjacket region of the latency-associated peptide domain of TGFB2 cause Camurati-Engelmann disease type II

Camurati-Engelmann disease (CED) is an autosomal dominant bone dysplasia characterized by progressive hyperostosis of the skull base and diaphyses of the long bones. CED is further divided into two subtypes, CED1 and CED2, according to the presence or absence of TGFB1 mutations, respectively. In this study, we used exome sequencing to investigate the genetic cause of CED2 in three pedigrees and identified two de novo heterozygous mutations in TGFB2 among the three patients. Both mutations were located in the region of the gene encoding the straitjacket subdomain of the latency-associated peptide (LAP) of pro-TGF-β2. Structural simulations of the mutant LAPs suggested that the mutations could cause significant conformational changes and lead to a reduction in TGF-β2 inactivation. An activity assay confirmed a significant increase in TGF-β2/SMAD signaling. In vitro osteogenic differentiation experiment using iPS cells from one of the CED2 patients showed significantly enhanced ossification, suggesting that the pathogenic mechanism of CED2 is increased activation of TGF-β2 by loss-of-function of the LAP. These results, in combination with the difference in hyperostosis patterns between CED1 and CED2, suggest distinct functions between TGFB1 and TGFB2 in human skeletal development and homeostasis.

A case of secondary hypertrophic osteoarthropathy from medieval Tuscany (central Italy, 10th-12th centuries CE)

OBJECTIVES

This study aims to provide a detailed evaluation of a case of secondary hypertrophic osteoarthropathy (HOA) and to explore insights into the presence and consequences of disease in medieval rural Italy.

MATERIALS

The skeleton of a male (US 4405) with an estimated age at death of 51-69 years excavated from the medieval rural site of Pieve di Pava (Siena, Italy).

METHODS

Macroscopic and radiological (x-ray, CT) analyses were performed.

RESULTS

Symmetrical extensive periosteal new bone formation on the diaphyseal and metaphyseal regions of this individual's long bones; the lower limbs were more extensively and severely affected than the upper limbs and the distal segments were more severely altered in comparison to the proximal ones.

CONCLUSIONS

The macroscopic and radiological features are highly consistent with a diagnosis of secondary HOA.

SIGNIFICANCE

The excellent state of preservation allowed the evaluation of rarely noted skeletal manifestations of HOA and provided insight into aspects of rural life in medieval Italy.

LIMITATIONS

Molecular analysis was not successful in sequencing the aDNA of tuberculosis, therefore the underlying primary cause of secondary HOA, whether pulmonary or extrapulmonary, remains obscure in this case.

SUGGESTION FOR THE FUTURE RESEARCH

It is advisable to regularly revisit the data available from osteoarchaeological collections in order to identify further cases of HOA, along with to further investigate the known cases to search for the underlying primary disease.

Physiologic Doses of TGF-β Improve the Composition of Engineered Articular Cartilage

For cartilage regeneration applications, transforming growth factor beta (TGF-β) is conventionally administered at highly supraphysiologic doses (10-10,000 ng/mL) in an attempt to cue cells to fabricate neocartilage that matches the composition, structure, and functional properties of native hyaline cartilage. While supraphysiologic doses enhance ECM biosynthesis, they are also associated with inducing detrimental tissue features, such as fibrocartilage matrix deposition, pathologic-like chondrocyte clustering, and tissue swelling. Here we investigate the hypothesis that moderated TGF-β doses (0.1-1 ng/mL), akin to those present during physiological cartilage development, can improve neocartilage composition. Variable doses of media-supplemented TGF-β were administered to a model system of reduced-size cylindrical constructs (Ø2-Ø3 mm), which mitigate the TGF-β spatial gradients observed in conventional-size constructs (Ø4-Ø6 mm), allowing for a novel assessment of the intrinsic effect of TGF-β doses on macroscale neocartilage properties and composition. The administration of physiologic TGF-β to reduced-size constructs yields neocartilage with native-matched sGAG content and mechanical properties while providing a more hyaline cartilage-like composition, marked by: 1) reduced fibrocartilage-associated type I collagen, 2) 77% reduction in the fraction of cells present in a clustered morphology, and 3) 45% reduction in the degree of tissue swelling. Physiologic TGF-β appears to achieve an important balance of promoting requisite ECM biosynthesis, while mitigating hyaline cartilage compositional deficits. These results can guide the development of novel physiologic TGF-β-delivering scaffolds to improve the regeneration clinical-sized neocartilage tissues.

Multifunctional silk vinyl sulfone-based hydrogel scaffolds for dynamic material-cell interactions

Biochemical and mechanical interactions between cells and the surrounding extracellular matrix influence cell behavior and fate. Mimicking these features in vitro has prompted the design and development of biomaterials, with continuing efforts to improve tailorable systems that also incorporate dynamic chemical functionalities. The majority of these chemistries have been incorporated into synthetic biomaterials, here we focus on modifications of silk protein with dynamic features achieved via enzymatic, "click", and photo-chemistries. The one-pot synthesis of vinyl sulfone modified silk (SilkVS) can be tuned to manipulate the degree of functionalization. The resultant modified protein-based material undergoes three different gelation mechanisms, enzymatic, "click", and light-induced, to generate hydrogels for in vitro cell culture. Further, the versatility of this chemical functionality is exploited to mimic cell-ECM interactions via the incorporation of bioactive peptides and proteins or by altering the mechanical properties of the material to guide cell behavior. SilkVS is well-suited for use in in vitro culture, providing a natural protein with both tunable biochemistry and mechanics.

Zoledronic acid improves bone quality and muscle function in a high bone turnover state

SUMMARY

Zoledronic acid (ZA) prevents muscle weakness in mice with bone metastases; however, its role in muscle weakness in non-tumor-associated metabolic bone diseases and as an effective treatment modality for the prevention of muscle weakness associated with bone disorders, is unknown. We demonstrate the role of ZA-treatment on bone and muscle using a mouse model of accelerated bone remodeling, which represents the clinical manifestation of non-tumor associated metabolic bone disease. ZA increased bone mass and strength and rescued osteocyte lacunocanalicular organization. Short-term ZA treatment increased muscle mass, whereas prolonged, preventive treatment improved muscle mass and function. In these mice, muscle fiber-type shifted from oxidative to glycolytic and ZA restored normal muscle fiber distribution. By blocking TGFβ release from bone, ZA improved muscle function, promoted myoblast differentiation and stabilized Ryanodine Receptor-1 calcium channel. These data demonstrate the beneficial effects of ZA in maintaining bone health and preserving muscle mass and function in a model of metabolic bone disease.

Context and significance

TGFβ is a bone regulatory molecule which is stored in bone matrix, released during bone remodeling, and must be maintained at an optimal level for the good health of the bone. Excess TGFβ causes several bone disorders and skeletal muscle weakness. Reducing excess TGFβ release from bone using zoledronic acid in mice not only improved bone volume and strength but also increased muscle mass, and muscle function. Progressive muscle weakness coexists with bone disorders, decreasing quality of life and increasing morbidity and mortality. Currently, there is a critical need for treatments improving muscle mass and function in patients with debilitating weakness. Zoledronic acid's benefit extends beyond bone and could also be useful in treating muscle weakness associated with bone disorders.

Hereditary Metabolic Bone Diseases: A Review of Pathogenesis, Diagnosis and Management

Hereditary metabolic bone diseases are characterized by genetic abnormalities in skeletal homeostasis and encompass one of the most diverse groups among rare diseases. In this review, we examine 25 selected hereditary metabolic bone diseases and recognized genetic variations of 78 genes that represent each of the three groups, including sclerosing bone disorders, disorders of defective bone mineralization and disorder of bone matrix and cartilage formation. We also review pathophysiology, manifestation and treatment for each disease. Advances in molecular genetics and basic sciences has led to accurate genetic diagnosis and novel effective therapeutic strategies for some diseases. For other diseases, the genetic basis and pathophysiology remain unclear. Further researches are therefore crucial to innovate ways to overcome diagnostic challenges and develop effective treatment options for these orphan diseases.

Clinical characteristics and identification of a novel TGFB1 variant in three unrelated Chinese families with Camurati-Engelmann disease

Background

To investigate the clinical characteristics and molecular diagnosis of Camurati‐Engelmann disease (CAEND) in Chinese individuals.

Methods

We recruited six patients aged 14 to 45 years in three unrelated families with CAEND, including five females and one male. Clinical manifestations, biochemical tests, and radiographic examinations were analyzed. The TGFB1 gene variants were further identified by Sanger sequencing. In addition, one female patient was followed up for 5 years.

Results

The onset age of the patients ranged from 1 to 6 years. All of them had family histories and consisted of an autosomal dominant inheritance pattern. Gait disturbance, fatigue, progressive bone pain, muscle atrophy, and weakness were the main complaints. Laboratory examinations revealed that the inflammatory markers were at high levels, in addition to the increased bone metabolism indicators. The thickened diaphysis of long bones and the narrowed medullary cavity was observed by radiography. Furthermore, bone scintigraphy detected abnormal symmetrical radioactive concentrations in the affected regions of bone. Sanger sequencing identified a missense heterozygous variant in exon 4 of the TGFB1 gene in families 1 and 2, resulting in Arg218Cys, which confirmed CAEND. Moreover, one novel variant c.669C > G in exon 4 of the TGFB1 gene harboring Cys223Trp was detected in family 3. Subsequent bioinformatics software predicted that the novel variant was pathogenic. Of interest, III:2 in family 3 experienced heart valve defects and tachycardia at birth, which had never been reported in CAEND patients before. Moreover, the response to drug treatment is also full of contradictions and is worthy of further study.

Conclusion

Besides the typical CAEND manifestations, the new phenotypic characteristics of tachycardia and heart valve defects were first reported in one woman carrying the novel variant p.Cys223Trp in TGFB1 the gene. In addition, we demonstrated that increased bone metabolism indicators and inflammatory markers may possess auxiliary diagnosis for CAEND.

Differential Diagnosis of Rare Diseases Involving Bilateral Lower Extremities with Similar 99mTc-MDP Bone Scan Patterns: Analysis of a Case Series

Here, we reported a panel of rare diseases involving bilateral lower extremities with similar imaging patterns on 99mTc-MDP bone scans. Glucose-6-phosphate dehydrogenase deficiency (G-6PD deficiency), Gaucher disease (GD), steroid-induced osteonecrosis, progressive diaphyseal dysplasia (PDD), Erdheim–Chester disease (ECD) and Langerhans cell sarcoma (LCS) were included and imaging characteristics were analyzed. The rare properties of these diseases and mimicking features on 99mTc-MDP bone scans rendered differential diagnosis difficult but necessary. We believe that the rarely known imaging features of the reported diseases will undoubtedly help nuclear medicine physicians make differential diagnoses in clinical practice.

Novel TBXAS1 variants in two Indian children with Ghosal hematodiaphyseal dysplasia: A concise report

Ghosal hematodiaphyseal dysplasia (GHDD) is a rare, autosomal recessive condition characterised by diaphyseal dysplasia of long bones with defective haematopoiesis. We describe 2 such cases with clinical and radiological evidence of GHDD. Molecular analysis revealed novel variants in TBXAS1 gene in both of them. Suspicion and confirmation of this entity is crucial in cases of refractory anemia with bony deformities, as the clinical manifestations in this entity are usually well responsive to corticosteroids.

Alteration of Bone Density, Microarchitecture, and Strength in Patients with Camurati-Engelmann Disease: Assessed by HR-pQCT

Camurati-Engelmann disease (CED) is a rare autosomal-dominant skeletal dysplasia caused by mutations in the transforming growth factor-β1 (TGFB1) gene. In this study, a retrospective review of patients with CED evaluated at Peking Union Medical College Hospital in Beijing, China, between November 30, 2000 and November 30, 2020 was conducted. Data including demographic data, manifestations, and examination results were characterized. Furthermore, bone geometry, density, and microarchitecture were assessed and bone strength was estimated by HR-pQCT. Results showed the median age at onset was 2.5 years. Common manifestations included pain in the lower limbs (94%, 17/18), abnormal gait (89%, 16/18), genu valgum (89%, 16/18), reduced subcutaneous fat (78%, 14/18), delayed puberty (73%, 8/11), muscle weakness (67%, 12/18), hearing loss (39%, 7/18), hepatosplenomegaly (39%, 7/18), exophthalmos or impaired vision or visual field defect (33%, 6/18), and anemia (33%, 7/18). Twenty-five percent (4/16) of patients had short stature. Serum level of alkaline phosphatase was elevated in 41% (7/17) of patients whereas beta-C-terminal telopeptide was elevated in 91% of patients (10/11). Among 12 patients, the Z-scores of two patients were greater than 2.5 at the femur neck and the Z-scores of five patients were lower than -2.5 at the femur neck and/or lumbar spine. HR-pQCT results showed lower volumetric BMD (vBMD), altered bone microstructure and lower estimated bone strength at the distal radius and tibia in patients with CED compared with controls. In addition, total volume bone mineral density and cortical volumetric bone mineral density at the radius were negatively correlated with age in patients with CED, but positively correlated with age in controls. In conclusion, the largest case series of CED with characterized clinical features in a Chinese population was reported here. In addition, HR-pQCT was used to investigate bone microstructure at the distal radius and tibia in nine patients with CED, and the alteration of bone density, microstructure, and strength was shown for the first time. © 2021 American Society for Bone and Mineral Research (ASBMR).

Aberrant activation of TGF-β1 induces high bone turnover via Rho GTPases-mediated cytoskeletal remodeling in Camurati-Engelmann disease

In the adult skeleton, the bone remodeling process involves a dynamic coordination between osteoblasts and osteoclasts, which is disrupted in diseases with high bone turnover rates and dysregulated transforming growth factor beta 1 (TGF-β1). However, little is known about how TGF-β1 signaling mediates bone resorption. Here, we described a pedigree with a heterozygous variant in TGF-β1 (R218C) that resulted in aberrant activation of TGF-β1 through an activating mechanism that caused Camurati-Engelmann disease (CED). We showed that CED patients have high levels of active Rho GTPases and the migration-related proteins Integrin β1 and Integrin β3 in their peripheral blood. HEK293T cells transfected with a plasmid encoding this mutant expressed high levels of TGF-β1 and active Rho GTPases. Furthermore, activation of Rho by TGF-β1 increased osteoclast formation and bone resorption, with increased migration of pre-osteoclasts, as well as cytoskeletal remodeling of pre-osteoclasts and mature osteoclasts. Importantly, pharmacological inhibition of Rho GTPases effectively rescued hyperactive TGF-β1-induced osteoclastogenesis in vitro. Overall, we propose that Rho GTPases mediate TGF-β1-induced osteoclastogenesis and suggest that Rho-TGF-β1 crosstalk is associated with high bone turnover in CED.

Improvement of Bone Health and Initiation of Puberty Development in Camurati-Engelmann Disease With Glucocorticoid and Losartan Treatment: A Case Report and Review of Literature

Camurati-Engelmann Disease (CED) is a rare sclerosing bone disease, sometimes associated delayed puberty. The treatment effect of glucocorticoid and angiotensin II receptor blocker (ARB) in bone health and puberty development remain unclear. We report a case of an 18-year-old girl who presented for a history of an enlarged head, pain of lower limbs, and no menstrual onset or breast development. Radiographs revealed thickening of skull and cortices in the diaphysis but sparse bone trabeculae in the spine and metaphysis. Sanger sequencing detected a mutation of c. 652C>T (p. R218C) in the gene TGFB1 and confirmed the diagnosis of CED. After treatment of a medium-to-small dosage of prednisone and losartan for 28 months, we observed improvement of bone mass in spine and hip and body fat mass and found initiation of puberty development. By a systemic review of current treatment strategies in patients with CED, we found that most cases reported relief of bone pain with treatment of glucocorticoid or ARB, but none has reported the outcome of hypogonadotropic hypogonadism. We propose that long-term use of glucocorticoid combined with ARB may inhibit the activation of TGFβ1 in CED, improve adipogenesis, and thus initiate puberty development and improve the bone mass in spine and hip.

Clinical characteristics and the influence of rs1800470 in patients with Camurati-Engelmann disease

BACKGROUND

Camurati-Engelmann disease (CED) is a sclerosing bone dysplasia caused by transforming growth factor β1 (TGFB1) gene variants.

OBJECTIVE

We aim to summarize the clinical characteristics and the efficacy of glucocorticoids in 14 individuals with CED, and explore the correlation between the phenotype and the SNP of rs1800470 (c.29C>T).

METHODS

Clinical, biochemical, radiological, and therapeutic data were collected from 14 patients. DNA was extracted for TGFB1 variants detection by Sanger sequencing.

RESULTS

The median onset and record age were 3.0 and 16.1 years, respectively. All patients manifested bone pain and decreased subcutaneous fat tissue. Inflammatory markers increased in over 60% of patients, and the median erythrocyte sedimentation rate (ESR) was 1.40 (0.50~3.67) of the upper limit of normal (ULN), and the median high sensitivity C reactive protein (hsCRP) was 1.71 (0.48~12.56) of ULN. There was a positive correlation between ESR and hsCRP (rs=0.806, p=0.003). Both ESR and hsCRP were negatively correlated with the levels of hemoglobin (HGB), calcium, and creatinine, but positively correlated with the level of alkaline phosphatase. Four known variants of TGFB1 were identified, including p.Tyr171Cys, p.Arg218Cys, p.Arg218His, and p.Cys225Arg. Moreover, 35.7% and 28.6% of them carried the heterozygous and homozygous SNP of c.29C>T, called C/T and T/T groups, respectively, but 35.7% of them were without c.29C>T (C/C group). The onset age, anthropometric data, percentages of different clinical manifestations, and biochemical parameters were comparable among the three groups. But there were increasing trends in levels of HGB and calcium and decreasing trends in ESR and hsCRP among C/C, C/T, and T/T groups in turn. Glucocorticoid improves the two inflammatory markers among CED patients.

CONCLUSION

The phenotype of CED is highly heterogeneous. There is no clear genotype-phenotype correlation, but it seems to have better trends of biochemical parameters in patients with CED carrying the T allele of rs1800470.

Surgery Treatment of an Adult Patient with Camurati-Engelmann Disease: A Case Report

CASE

A 40-year-old Colombian woman presented with a 7-year history of progressive lower-limb pain. Sclerosis of the diaphyseal tibia and femur was observed in her latest x-ray images. A narrowing of the medullary canal is observed in Camurati-Engelmann disease (CED), a rare and progressive diaphyseal dysplasia that was confirmed in this patient by genetic testing. Medical treatment was unsuccessful; thus, surgical treatment consisted of decompression by drilling of the medullary canal was performed, achieving successful pain release.

CONCLUSION

Surgical treatment should be considered for patients with CED when the medical treatment is unsuccessful because doing so reduces bone overgrowth, leading to pain relief.

Losartan as a Steroid-Sparing Adjunct in a Patient With Features of Refractory Camurati-Engelmann Disease

Objective

The treatment of Camurati-Engelmann disease (CED) involves the use of glucocorticoids, analgesics, and bisphosphonates; experience with the use of losartan is limited. Our objective was to describe the case of a patient diagnosed with CED whose symptoms remained refractory while on steroids and bisphosphonates and who was successfully treated with losartan.

Case Report

A 27-year-old woman presented with bone pain involving her extremities and large joints for 1 year. Clinical examination revealed bone tenderness and proximal myopathy with elevated C-terminal peptide of type 1 collagen (1617 pg/mL; normal range, 137-573 pg/mL) and N-terminal propeptide of type 1 procollagen levels (163 ng/mL; normal range, 5.1-58.3 ng/mL). Calcium (9.4 mg/dL; normal range, 8.3-10.4 mg/dL), phosphate (3.4 mg/dL; normal range, 2.5-4.5 mg/dL), and parathyroid hormone (62 pg/mL; normal range, 8-80 pg/mL) levels were within the normal range. Radiographs showed hyperostosis involving the diaphyseal region of long bones of the lower and upper limbs, and a provisional diagnosis of CED was made. She was treated with prednisolone, 30 mg daily, with which she reported some improvement. As exogenous Cushing syndrome had developed in her because of prednisolone, its dose was tapered. Subsequently, her bone pain worsened. Thereafter, she was initiated on oral alendronate. Due to persistent pain, losartan was added, after which she had marked decrease in bone pain with a reduction in the C-terminal peptide of type 1 collagen (375 pg/mL) and N-terminal propeptide of type 1 procollagen (50 ng/mL) levels.

Discussion

Occasionally, CED presents therapeutic challenges, and when its symptoms remain refractory to conventional doses of steroids and bisphosphonates, other options may be needed. The abovementioned patient was initiated on losartan, which acts by downregulation of transforming growth factor β1, leading to the reduction in pain.

Conclusion

Losartan downregulates transforming growth factor β1 and may be offered as a steroid-sparing option in individuals diagnosed with CED if symptoms remain refractory to conventional treatment.

Cortical bone development, maintenance and porosity: genetic alterations in humans and mice influencing chondrocytes, osteoclasts, osteoblasts and osteocytes

Cortical bone structure is a crucial determinant of bone strength, yet for many years studies of novel genes and cell signalling pathways regulating bone strength have focused on the control of trabecular bone mass. Here we focus on mechanisms responsible for cortical bone development, growth, and degeneration, and describe some recently described genetic-driven modifications in humans and mice that reveal how these processes may be controlled. We start with embryonic osteogenesis of preliminary bone structures preceding the cortex and describe how this structure consolidates then matures to a dense, vascularised cortex containing an increasing proportion of lamellar bone. These processes include modelling-induced, and load-dependent, asymmetric cortical expansion, which enables the cortex's transition from a highly porous woven structure to a consolidated and thickened highly mineralised lamellar bone structure, infiltrated by vascular channels. Sex-specific differences emerge during this process. With aging, the process of consolidation reverses: cortical pores enlarge, leading to greater cortical porosity, trabecularisation and loss of bone strength. Each process requires co-ordination between bone formation, bone mineralisation, vascularisation, and bone resorption, with a need for locational-, spatial- and cell-specific signalling pathways to mediate this co-ordination. We will discuss these processes, and a number of cell-signalling pathways identified in both murine and human genetic studies to regulate cortical bone mass, including signalling through gp130, STAT3, PTHR1, WNT16, NOTCH, NOTUM and sFRP4.

Therapeutic targeting of TGF-β in cancer: hacking a master switch of immune suppression

Cancers may escape elimination by the host immune system by rewiring the tumour microenvironment towards an immune suppressive state. Transforming growth factor-β (TGF-β) is a secreted multifunctional cytokine that strongly regulates the activity of immune cells while, in parallel, can promote malignant features such as cancer cell invasion and migration, angiogenesis, and the emergence of cancer-associated fibroblasts. TGF-β is abundantly expressed in cancers and, most often, its abundance associated with poor clinical outcomes. Immunotherapeutic strategies, particularly T cell checkpoint blockade therapies, so far, only produce clinical benefit in a minority of cancer patients. The inhibition of TGF-β activity is a promising approach to increase the efficacy of T cell checkpoint blockade therapies. In this review, we briefly outline the immunoregulatory functions of TGF-β in physiological and malignant contexts. We then deliberate on how the therapeutic targeting of TGF-β may lead to a broadened applicability and success of state-of-the-art immunotherapies.

The combined prevalence of classified rare rheumatic diseases is almost double that of ankylosing spondylitis

BACKGROUND

Rare diseases (RDs) affect less than 5/10,000 people in Europe and fewer than 200,000 individuals in the United States. In rheumatology, RDs are heterogeneous and lack systemic classification. Clinical courses involve a variety of diverse symptoms, and patients may be misdiagnosed and not receive appropriate treatment. The objective of this study was to identify and classify some of the most important RDs in rheumatology. We also attempted to determine their combined prevalence to more precisely define this area of rheumatology and increase awareness of RDs in healthcare systems. We conducted a comprehensive literature search and analyzed each disease for the specified criteria, such as clinical symptoms, treatment regimens, prognoses, and point prevalences. If no epidemiological data were available, we estimated the prevalence as 1/1,000,000. The total point prevalence for all RDs in rheumatology was estimated as the sum of the individually determined prevalences.

RESULTS

A total of 76 syndromes and diseases were identified, including vasculitis/vasculopathy (n = 15), arthritis/arthropathy (n = 11), autoinflammatory syndromes (n = 11), myositis (n = 9), bone disorders (n = 11), connective tissue diseases (n = 8), overgrowth syndromes (n = 3), and others (n = 8). Out of the 76 diseases, 61 (80%) are classified as chronic, with a remitting-relapsing course in 27 cases (35%) upon adequate treatment. Another 34 (45%) diseases were predominantly progressive and difficult to control. Corticosteroids are a therapeutic option in 49 (64%) syndromes. Mortality is variable and could not be determined precisely. Epidemiological studies and prevalence data were available for 33 syndromes and diseases. For an additional eight diseases, only incidence data were accessible. The summed prevalence of all RDs was 28.8/10,000.

CONCLUSIONS

RDs in rheumatology are frequently chronic, progressive, and present variable symptoms. Treatment options are often restricted to corticosteroids, presumably because of the scarcity of randomized controlled trials. The estimated combined prevalence is significant and almost double that of ankylosing spondylitis (18/10,000). Thus, healthcare systems should assign RDs similar importance as any other common disease in rheumatology.

Controlling BMP growth factor bioavailability: The extracellular matrix as multi skilled platform

Bone morphogenetic proteins (BMPs) belong to the TGF-β superfamily of signaling ligands which comprise a family of pluripotent cytokines regulating a multitude of cellular events. Although BMPs were originally discovered as potent factors extractable from bone matrix that are capable to induce ectopic bone formation in soft tissues, their mode of action has been mostly studied as soluble ligands in absence of the physiologically relevant cellular microenvironment. This micro milieu is defined by supramolecular networks of extracellular matrix (ECM) proteins that specifically target BMP ligands, present them to their cellular receptors, and allow their controlled release. Here we focus on functional interactions and mechanisms that were described to control BMP bioavailability in a spatio-temporal manner within the respective tissue context. Structural disturbance of the ECM architecture due to mutations in ECM proteins leads to dysregulated BMP signaling as underlying cause for connective tissue disease pathways. We will provide an overview about current mechanistic concepts of how aberrant BMP signaling drives connective tissue destruction in inherited and chronic diseases.

Significant Improvement After Surgery for a Symptomatic Osteoblastoma in a Patient with Camurati-Engelmann Disease: Case Report and Literature Review

Camurati-Engelmann disease (CED) is a rare, progressive diaphyseal dysplasia characterized as diaphyseal hyperostosis and sclerosis of the long bones. Corticosteroids, bisphosphonates, and losartan have been reported to be effective systemic medications used to reduce CED symptoms. There are no reports of osteoblastoma in patients with CED, and osteoblastoma in the distal radius is rare. We present a patient diagnosed with CED, based on radiological and histological examinations, at 11 years old. At 22 years old, she experienced severe pain in her right forearm and was treated with bisphosphonate, losartan, and prednisolone; however, the pain continued. An expansive and sclerotic lesion at the distal radius was observed on radiography. A follow-up plain radiograph indicated that the lesion was growing. Fluorodeoxyglucose positron emission tomography revealed solitary, intense radiotracer uptake, and a biopsy and surgical resection were performed due to suspected malignancy. Pathologic analysis showed anastomosing bony trabeculae rimmed by osteoblasts observed in a loose fibrovascular stroma. The lesion was diagnosed as an osteoblastoma. Following bone excision and artificial bone grafting, the patient's severe pain almost completely disappeared. At final follow-up, no evidence of osteoblastoma recurrence was noted. To our knowledge, this is the first case report of osteoblastoma arising in a patient with CED. Bone excision and artificial bone grafting may be a treatment option for local symptomatic osteoblastoma in patients with CED.

A critical review of the anthropological and paleopathological literature on osteopetrosis as an ancient rare disease (ARD)

OBJECTIVE

A reappraisal of the available evidence of osteopetrosis in the archaeological record as first step in promoting new approaches to rare diseases in paleopathology.

MATERIALS AND METHODS

Three different approaches are combined: a survey of the last 50 years of bioarchaeological publications; an online search addressing six of the more widely used search engines; macroscopic and radiographic analyses of the human remains from the Neolithic site of Palata 2 (Italy).

RESULTS

The combined results of the literature survey and the online search identified six cases of osteopetrosis. The majority of search hits place this disease into differential diagnoses. The investigation of the remains from Palata 2, one of the six cases in literature, indicates a non-specific sclerosis of the cranial vault.

CONCLUSIONS

Of the six cases of osteopetrosis, only two, one of the autosomal-recessive type (ARO) and one of the autosomal-dominant type (ADO), are supported by direct osteoarchaeological evidence. Therefore, inaccurate differential diagnoses generate an inflated number of cases in the paleopathological record.

SIGNIFICANCE

This reappraisal calls for a more informed and evidence-based approach to osteopetrosis and, more generally, to rare diseases in paleopathology.

LIMITATIONS

Lack of specific publications on osteopetrosis; more case studies may be present in "gray literature".

SUGGESTIONS FOR FURTHER RESEARCH

Cases of osteopetrosis from archaeological and historical collections as well as medical literature are needed to increase knowledge about this rare disease. More precise differential diagnoses are required, particularly when dealing with rare diseases.

Imaging of Congenital Skeletal Disorders

Osteochondrodysplasias are the result of the expression of gene mutations. The phenotypes in osteochondrodysplasias evolve through life, with the possibility that previously unaffected bones may be involved at later stages of growth. Due to the variable time of onset, the diagnosis may be made prenatally, at birth, or later. Certainty in the diagnosis is sometimes only achieved as the patient matures and the disease evolves. Radiographic evaluation is a fundamental part of the diagnostic work-up of congenital skeletal disorders and in most cases the first tool used to arrive at a diagnosis. This review describes the imaging characteristics, specific signs, and evolution of several skeletal dysplasias in which diagnosis may be directly or indirectly suggested by radiologic findings. A definitive accurate diagnosis of a congenital skeletal abnormality is necessary to help provide a prognosis of expected outcomes and to counsel parents and patients.

Sclerotic bone lesions caused by non-infectious and non-neoplastic diseases: a review of the imaging and clinicopathologic findings

Bone sclerosis is a focal, multifocal, or diffuse increase in the density of the bone matrix on radiographs or computed tomography (CT) imaging. This radiological finding can be caused by a broad spectrum of diseases, such as congenital and developmental disorders, depositional disorders, and metabolic diseases. The differential diagnosis can be effectively narrowed by an astute radiologist in the light of the clinical picture and typical findings on imaging. Some of these lesions are rare and have been described as case reports and series in the literature. This article aims to collate the clinical-radiologic findings of non-infectious and non-neoplastic causes of bone sclerosis with relevant imaging illustrations.

Signaling Pathways in Bone Development and Their Related Skeletal Dysplasia

Bone development is a tightly regulated process. Several integrated signaling pathways including HH, PTHrP, WNT, NOTCH, TGF-β, BMP, FGF and the transcription factors SOX9, RUNX2 and OSX are essential for proper skeletal development. Misregulation of these signaling pathways can cause a large spectrum of congenital conditions categorized as skeletal dysplasia. Since the signaling pathways involved in skeletal dysplasia interact at multiple levels and have a different role depending on the time of action (early or late in chondrogenesis and osteoblastogenesis), it is still difficult to precisely explain the physiopathological mechanisms of skeletal disorders. However, in recent years, significant progress has been made in elucidating the mechanisms of these signaling pathways and genotype-phenotype correlations have helped to elucidate their role in skeletogenesis. Here, we review the principal signaling pathways involved in bone development and their associated skeletal dysplasia.

Anterior Total Hip Arthroplasty With Bulk Femoral Head Autograft in a Patient With Camurati-Engelmann Disease

Camurati-Engelmann disease (CED) is an extremely rare, sclerosing bone disorder of intramedullary ossification with only 300 reported cases worldwide. The pathogenesis is related to activating mutations in transforming growth factor beta 1, which results in bilateral, symmetric hyperostosis affecting primarily the diaphysis of long bones. Despite effective pharmacological treatment options, the diagnosis of CED is problematic owning to its rarity and variability of clinical presentation. We present a patient with known CED with advanced early hip osteoarthritis, secondary to underlying hip dysplasia, for which she underwent a successful total hip arthroplasty via a direct anterior approach with the use of bulk femoral head autograft to reconstruct her native acetabulum.

Genetic and Epigenetic Fine-Tuning of TGFB1 Expression Within the Human Osteoarthritic Joint

OBJECTIVE

Osteoarthritis (OA) is an age-related disease characterized by articular cartilage degeneration. It is largely heritable, and genetic screening has identified single-nucleotide polymorphisms (SNPs) marking genomic risk loci. One such locus is marked by the G>A SNP rs75621460, downstream of TGFB1. This gene encodes transforming growth factor β1, the correct expression of which is essential for cartilage maintenance. This study investigated the regulatory activity of rs75621460 to characterize its impact on TGFB1 expression in disease-relevant patient samples (n = 319) and in Tc28a2 immortalized chondrocytes.

METHODS

Articular cartilage samples from human patients were genotyped, and DNA methylation levels were quantified using pyrosequencing. Gene reporter and electrophoretic mobility shift assays were used to determine differential nuclear protein binding to the region. The functional impact of DNA methylation on TGFB1 expression was tested using targeted epigenome editing.

RESULTS

The analyses showed that SNP rs75621460 was located within a TGFB1 enhancer region, and the OA risk allele A altered transcription factor binding, with decreased enhancer activity. Protein complexes binding to A (but not G) induced DNA methylation at flanking CG dinucleotides. Strong correlations between patient DNA methylation levels and TGFB1 expression were observed, with directly opposing effects in the cartilage and the synovium at this locus. This demonstrated biologic pleiotropy in the impact of the SNP within different tissues of the articulating joint.

CONCLUSION

The OA risk SNP rs75621460 impacts TGFB1 expression by modulating the function of a gene enhancer. We propose a mechanism by which the SNP impacts enhancer function, providing novel biologic insight into one mechanism of OA genetic risk, which may facilitate the development of future pharmacologic therapies.

A new LRP6 variant and Camurati-Engelmann-like disease

INTRODUCTION

Camurati-Engelmann disease is a rare autosomal dominant bone dysplasia belonging to the group of craniotubular hyperostoses. Genetic analysis classically shows mutation on TGFβ1 gene.

CASE REPORT

A young woman was hospitalized with intense pain in lower limbs, associated to radiographic hyperostosis and sclerosis of the long bones.

RESULTS

Mutation on LRP6 has recently been associated to high bone mass. In this case report, a rare missense variant on LRP6 gene was associated to radiographic features of Camurati-Engelmann.

CONCLUSIONS

More studies should be conducted to assess the pathological role of this variant in Camurati-Engelmann-like disease.

Decompression of the internal auditory canal via the retrosigmoid approach in a patient with Camurati-Engelmann disease: illustrative case

BACKGROUND

Camurati-Engelmann disease (CED) is a rare condition characterized by hyperostosis of the long bones and skull base. Symptoms include contractures and pain in affected extremities but can also include manifestations of cranial hyperostosis such as intracranial hypertension, Chiari malformation, exophthalmia, frontal bossing, and several cranial neuropathies due to cranial foraminal stenosis.

OBSERVATIONS

This report describes a 27-year-old patient with suspected CED who developed progressive intermittent facial nerve paresis, hemifacial spasms, and a decrease in hearing. There were no symptoms of increased intracranial pressure or vertigo. Radiological evaluation showed a significant thickening of the skull base with serious bilateral internal auditory canal stenosis. Because of the progressive nature of the aforementioned cranial neuropathies in combination with the correlating severe radiological compression, a surgical decompression of the facial nerve and vestibulocochlear nerve was performed via a retrosigmoid approach with intraoperative monitoring. Postoperative facial nerve function was intact. Hearing and vestibular function were unchanged. There were no more episodes of facial nerve palsy or spasm.

LESSONS

To the authors' knowledge, this is the first report to describe decompression of the internal auditory canal via a retrosigmoid approach for symptomatic facial and cochlear nerve compression in a patient with CED.

Efficacy of denosumab therapy after alendronate treatment for a 66-year-old woman with Camurati-Engelmann disease and osteoporosis: a case report

Camurati-Engelmann disease (CED) is characterized by hyperostois of multiple long bones. Although several treatments for CED complicated with osteoporosis have been described, it remains controversial whether such therapy is suitable for osteoporotic CED patients. We retrospectively enrolled a 66-year-old female patient with osteoporosis in CED who underwent denosumab therapy for 14 months. Denosumab was commenced after 3 years of alendronate treatment. Fourteen months later, lumbar and total hip bone mineral density showed gains of 5.9% and 6.4%, respectively. Bone turnover markers were also improved during follow-up. No fractures or other complications were recorded during the observational period. This is the first study describing denosumab treatment for an osteoporotic CED patient. Our findings indicate that denosumab is an effective therapy option for osteoporosis in CED.

Fibrous Dysplasia, Paget's Disease of Bone, and Other Uncommon Sclerotic Bone Lesions of the Craniofacial Bones

Imaging studies of the brain, head and neck, sinuses, and dental computed tomography are among the most frequently performed procedures in radiologic departments. Systematic evaluation in the bone window may reveal common and uncommon sclerotic osseous abnormalities of the craniofacial skeleton.Most of these findings are incidental and unrelated to the initial clinical indications. Sporadically symptoms may arise due to lesional mass effect with compression on adjacent structures and neuroforaminal encroachment, resulting in proptosis, vision, or hearing loss. Other symptoms include craniofacial deformity, mandibular occlusion deformity, and local pain.This article reviews the most common disorders characterized by an increased bone density involving the craniofacial bones including fibrous dysplasia, Paget's disease of bone, meningioma with associated hyperostosis, and osteoma. Finally, typical examples of rarer sclerosing bone dysplasias are discussed as well.Emphasis is placed on imaging features and the differential diagnosis.

A patient with Camurati-Engelmann disease presenting bilateral TMJ ankylosis: A case report

Camurati-Engelmann Disease (CED), also known as progressive diaphyseal dysplasia, is a rare congenital disorder inherited in an autosomal-dominant pattern, most commonly affecting the skull and diaphysis of long tubular bones. Clinical symptoms start in early age and include ostealgia, muscle atrophy and weakness in the lower limbs, generalized fatigue in addition to gait disturbances (Garcia Armario and Lebron, 2011, Andreu-Arasa et al., 2019; Fyrgiola et al., 2017; Damiá and García Gómez, 2017; Mwasamwaja et al., 2018). CED is believed to be caused by mutation in the gene coding for Transforming Growth Factor ß-1 (TGFß-1) (Fyrgiola et al. 2017). This article presents a rare clinical case of CED, with bilaterally hypertrophic articular apparatus and subsequent ankylosis. A 33-year-old male is reported with temporomandibular joint (TMJ) ankylosis, bone pain, generalized muscle weakness, abnormal gait and bulging eyes. Diagnosis of CED was based on genetic mapping performed by genetist. Upon clinical and radiological examination, a massive bony mass in the condyloid and coronoid was discovered and treatment of choice was surgical resection and installation of bilateral stock articular prostheses.

A Case Report of a 44-Year-Old Woman With Camurati-Englemann Disease: A Case Report

CASE

A 44-year-old woman presented with easy fatigability, diplopia, dizziness, and a 2-year history of pelvic, hip, and lower extremity aching and pain. Radiograph, magnetic resonance imaging, computed tomography, and histopathologic imaging studies were obtained. Hypersclerosis of the affected bones led to the initiation of a sclerotic bone dysplasia workup and sequencing of the transforming growth factor beta 1 gene located on chromosome 19q13 revealed a heterozygous rare missense variant in exon-4, leading to a final diagnosis of Camurati-Engelmann disease (CED). Medical treatment thus far has had a minimal effect on her symptoms, and the patient continues to be followed.

CONCLUSIONS

This specific mutation has been reported only once previously in a patient with CED. This case report expands the typical phenotype associated with CED in association with the c.667T>C, p.Cys223Arg variant.

Genetic testing is useful in adults with limited phenotypes of genetic skeletal conditions

We show the value of genetic screening in 3 adults with limited phenotypes of three bone sclerosing genetic disease (GD): osteopetrosis (OPT), Camurati-Engelmann disease (CED) and pycnodysostosis.

INTRODUCTION

OPT, CED and pycnodysostosis are three rare bone diseases often diagnosed in childhood. However, some atypical phenotypes raise the problem of delayed diagnosis in adults. Genetic tests may then be useful to establish a formal diagnosis.

METHODS

We report 3 cases of adult patients with symptomatic or asymptomatic bone sclerosing lesions for whom the clinical, radiological and biological explorations were atypical and did not allow a formal diagnosis. These unusual descriptions led to the search for genetic mutations.

RESULTS

These 3 cases of limited phenotypes were associated with unknown or poorly described variants of 3 rare bone genetic diseases.

CONCLUSIONS

Genetic tests proved useful to establish the diagnosis and manage the condition of adults with rare bone sclerosing GD.

Juvenile Paget's disease with compound heterozygous mutations in TNFRSF11B presenting with recurrent clavicular fractures and a mild skeletal phenotype

Juvenile Paget's disease (JPD) is a rare recessively-inherited bone dysplasia. The great majority of cases described to date have had homozygous mutations in TNFRSF11B, the gene encoding osteoprotegerin. We describe a boy who presented with recurrent clavicular fractures following minor trauma (8 fractures from age 2 to 11). He was of normal height and despite mild lateral bowing of the thighs and anterior bowing of the shins he remained physically active. Abnormal modelling was noted in ribs and humeri on clavicular radiographs, and a skeletal survey at the age of 7 showed generalised diaphyseal expansion of the long bones with thickening of the periosteal and endosteal surfaces of the cortices. On biochemical evaluation, serum alkaline phosphatase was noted to be persistently elevated. The diagnosis of JPD was confirmed by the finding of compound heterozygous mutations in TNFRSF11B: a maternally-inherited A>G missense mutation at position 1 of the first amino acid codon (previously reported) and a paternally-inherited splice acceptor site mutation in intron 3 at a highly conserved position (not previously reported). Bioinformatics analysis suggested both mutations were disease-causing. Compound heterozygote mutations in TNFRSF11B causing JPD have been previously reported only once - in a boy who also had a relatively mild skeletal phenotype. The milder features may lead to delay in diagnosis and diagnostic confusion with other entities, but the extraskeletal features of JPD may nonetheless develop.

Total Hip Arthroplasty in a Patient with Camurati-Engelmann Disease: A Case Report

CASE

We review the case of a 44-year-old man with Camurati-Engelmann disease, who presented with chronic right hip pain that did not improve following intra-articular hip injections. He was functionally debilitated because of the worsening pain. Routine radiographs demonstrated severe right hip osteoarthritis and severe diaphyseal sclerosis of the femur. To address the narrowed medullary cavity, appropriate reaming of the diaphysis and broaching to fill the metaphysis were performed. The patient underwent an uncemented total hip arthroplasty that resulted in an excellent recovery with no complications.

CONCLUSION

Uncemented total hip arthroplasty serves as a good option for patients with hip osteoarthritis secondary to Camurati-Engelmann disease. Anticipation of potential operative challenges is the key to avoiding complications and achieving an optimal, durable outcome.

When a pedodontic examination leads to the diagnosis of osteopetrosis: A case report

BACKGROUND/AIM

Osteopetrosis is an inherited disease characterized by increased bone density. Its genetic variability results in various phenotype expressions, whereas clinically are classified in three types: malignant infantile, intermediate and adult. The various oral manifestations of the disease give a crucial role to the pediatric dentists in diagnosis.

CASE PRESENTATION

A 7-year-old girl with persistent swelling on right cheek visited a pedodontic clinic. After extra- and intra-oral examination/findings, the patient was referred for further investigation concerning a possible general pathological background. An extraction, included in the initial dental treatment plan, led to the diagnosis of osteopetrosis. Various medical examinations co-led to the diagnosis of osteopetrosis but without genetic identification. Extractions of carious teeth, under general anesthesia, and full cover or sealants, on chair, of unaffected teeth were conducted respectively to minimize the microbial load and to prevent from osteomyelitis relapse and new caries. Two more general anesthesia sessions took place due to relapse of lower jaw osteomyelitis. Follow-up was conducted every 3 months for 2 years.

CONCLUSION

Osteopetrosis' diagnosis can be triggered by its oral manifestations (rampant caries, osteonecrosis, enamel defects, malformed roots/crowns, missing teeth), for which the pediatric dentist could be the first observer. Management of these patients needs multidisciplinary approach and follow-up appointments should be very frequent.

Observations on the Natural History of Camurati-Engelmann Disease

Camurati-Engelmann disease (OMIM 31300) is a rare cranio-tubular bone dysplasia characterized by osteosclerosis of the long bones and skull caused by dominantly-inherited mutations in the transforming growth factor beta 1 (TGFB1) gene. A wide variation in phenotype has been recognized, even within families carrying the same mutation. In addition, aspects of the natural history of the disorder, in particular whether it is always progressive or can remit spontaneously, remain uncertain. In a large kindred carrying a TGFB1 gene mutation (c.653G > A; p.R218H) we have attempted to clarify the extent of phenotypic variability and the natural history of the disease through detailed individual histories of symptoms, and skeletal imaging by both radiography and scintigraphy. Only one subject had the classical childhood onset with bone pain in the legs and gait disturbance. Eight subjects reported the onset of leg pain in their teenage years that, by their early 20s, had either resolved or persisted at a low level. Two of these eight later developed cranial nerve palsies. There was a wide variation in the radiographic appearance in adults, but disease extent and activity in long bones, as assessed by scintigraphy, was inversely correlated with age (p < 0.025). In younger subjects the radiographic and scintigraphic appearances were concordant, but in older subjects the scintigram could be quiescent despite florid radiographic changes. Sequential scintigrams in two subjects showed reduced activity in the later scan. One subject had suffered meningoencephalitis in early childhood that resulted in paresis of one arm. The affected arm showed markedly less disease involvement, implicating mechanical or growth factors in its etiology. Our data suggest that the natural history of Camurati-Engelmann disease can be benign, and that disease activity commonly attenuates in adulthood. Severe cases of childhood onset and/or with cranial nerve involvement, may occur only in a minority of mutation carriers. © 2019 American Society for Bone and Mineral Research.

Camurati-Engelmann Disease

Camurati-Engelmann disease or progressive diaphyseal dysplasia is a rare autosomal dominant sclerosing bone dysplasia. Mainly the skull and the diaphyses of the long tubular bones are affected. Clinically, the patients suffer from bone pain, easy fatigability, and decreased muscle mass and weakness in the proximal parts of the lower limbs resulting in gait disturbances. The disease-causing mutations are located within the TGFβ-1 gene and expected to or thought to disrupt the binding between TGFβ1 and its latency-associated peptide resulting in an increased signaling of the pathway and subsequently accelerated bone turnover. In preclinical studies, it was shown that targeting the type I receptor ameliorates the high bone turnover. In patients, treatment options are currently mostly limited to corticosteroids that may relieve the pain, and improve the muscle weakness and fatigue. In this review, the clinical and radiological characteristics as well as the molecular genetics of this condition are discussed.

Identification of new therapeutic targets for osteoarthritis through genome-wide analyses of UK Biobank data

Osteoarthritis is the most common musculoskeletal disease and the leading cause of disability globally. Here, we perform a genome-wide association study for osteoarthritis (77,052 cases and 378,169 controls), analysing 4 phenotypes: knee osteoarthritis, hip osteoarthritis, knee and/or hip osteoarthritis, and any osteoarthritis. We discover 64 signals, 52 of them novel, more than doubling the number of established disease loci. Six signals fine map to a single variant. We identify putative effector genes by integrating eQTL colocalization, fine-mapping, human rare disease, animal model, and osteoarthritis tissue expression data. We find enrichment for genes underlying monogenic forms of bone development diseases, and for the collagen formation and extracellular matrix organisation biological pathways. Ten of the likely effector genes, including TGFB1, FGF18, CTSK and IL11 have therapeutics approved or in clinical trials, with mechanisms of action supportive of evaluation for efficacy in osteoarthritis.

Camurati-Engelmann Disease with Good Treatment Response to Losartan

Camurati–Engelmann disease (CED) or progressive diaphyseal dysplasia is a rare autosomal dominant inherited condition which belongs to the group of craniotubular hyperostosis. A 24-year-old man presented with insidious onset, progressive pain over both legs, and forearms for 3 years. He was born as the second child of a nonconsanguineous union by vaginal delivery at term without any complications. The clinical, radiological, and histopathological features were suggestive of CED. Transforming growth factor-β1 sequence analysis revealed a missense mutation (c.652C>T; p. Arg218Cys) confirming the diagnosis. He had a good response to treatment with Losartan. CED should be considered in the differential diagnosis of patients presenting with nonspecific limb pains and radiological features of skeletal dysplasia. Early recognition and diagnosis play a crucial role in management. This case discuss regarding the potential benefits of the drug losartan in the management of a rare bone disease for which the evidence from previous literature is scarce.

Sclerosing bone dysplasias

The group of sclerosing bone dysplasia's is a clinically and genetically heterogeneous group of rare bone disorders which, according to the latest Nosology and classification of genetic skeletal disorders (2015), can be subdivided in three subgroups; the neonatal osteosclerotic dysplasias, the osteopetroses and related disorders and the other sclerosing bone disorders. Here, we give an overview of the most important radiographic and clinical symptoms, the underlying genetic defect and potential treatment options of the different sclerosing dysplasias included in these subgroups.

Bone-targeted delivery of TGF-β type 1 receptor inhibitor rescues uncoupled bone remodeling in Camurati-Engelmann disease

Camurati-Engelmann disease (CED) is a genetic bone-modeling disorder mainly caused by mutations in the gene that encodes transforming growth factor-β1 (TGF-β1). Symptoms of CED include bone pain, fractures, and dysplasia. Currently, effective therapies for bone fracture and dysplasia in CED are urgently needed. We have demonstrated that TGF-β1 is a coupling factor for bone remodeling and is aberrantly activated in CED. Daily injection of TGF-β type 1 receptor inhibitor (TβR1I) attenuated CED symptoms, but this systemic administration caused serious side effects. In this study, we created a conjugate linking TβR1I and alendronate, which delivered TβR1I specifically to bone. After weekly injection of the conjugate for 8 weeks, normal bone morphology and remodeling in CED mice was maintained with a minimum effective dose 700 times lower than TβR1I injection. Additionally, we found that the conjugate restored normal bone turnover by reducing the number of osteoblasts and osteoclasts, maintained a regular osteogenic microenvironment by regulating the formation of CD31 and Endomucin double-positive vessels, and preserved ordinary bone formation via inhibition of the migration of leptin-receptor-positive cells. Thus, targeting delivery of TβR1I to bone is a promising therapy for CED and other uncoupled bone remodeling disorders.

Camurati-Engelmann disease: a case report from sub-Saharan Africa

Camurati–Engelmann disease is a rare autosomal dominant inherited condition belonging to the group of craniotubular hyperostosis with characteristic radiological features of the diaphyses of the long bones and the skull. A 35-year-old female is reported presenting with bone pain and waddling gait, since the age of 20 years. Motor activities were limited since the age of 10 years. Palpable bones, muscle weakness and protrusion of eyes were noted. Radiologically, hyperostosis of long bones was seen. Based on history, clinical and radiological features Camurati–Engelmann disease was diagnosed. Sequence analysis of the transforming growth factor β1 (TGFB1) gene revealed a missense mutation (c.652C>T; p.Arg218Cys). She is the first molecularly confirmed case in sub-Saharan Africa. It is emphasized that Camurati–Engelmann disease is included in the differential diagnosis of persistent bone pain, but also of abnormal childhood motor development in order to avoid unnecessary investigations and inadequate management.

Anabolic Therapy for the Treatment of Osteoporosis in Childhood

PURPOSE OF REVIEW

Numerous forms of osteoporosis in childhood are characterized by low bone turnover (for example, osteoporosis due to neuromuscular disorders and glucocorticoid exposure). Anti-resorptive therapy, traditionally used to treat osteoporosis in the young, is associated with further reductions in bone turnover, raising concerns about the long-term safety and efficacy of such therapy. These observations have led to increasing interest in the role of anabolic therapy to treat pediatric osteoporosis.

RECENT FINDINGS

While growth hormone and androgens appears to be relatively weak anabolic modulators of bone mass, emerging therapies targeting bone formation pathways (anti-transforming growth factor beta antibody and anti-sclerostin antibody) hold considerable promise. Teriparatide remains an attractive option that merits formal study for patients post-epiphyseal fusion, although it must be considered that adult studies have shown its effect is blunted when administered following bisphosphonate therapy. Mechanical stimulation of bone through whole body vibration therapy appears to be much less effective than bisphosphonate therapy for treating osteoporosis in children. New anabolic therapies which target important pathways in skeletal metabolism merit further study in children, including their effects on fracture risk reduction and after treatment discontinuation.

Human Genetics of Sclerosing Bone Disorders

PURPOSE OF REVIEW

The group of sclerosing bone disorders encompasses a variety of disorders all marked by increased bone mass. In this review, we give an overview of the genetic causes of this heterogeneous group of disorders and briefly touch upon the value of these findings for the development of novel therapeutic agents.

RECENT FINDINGS

Advances in the next-generation sequencing technologies are accelerating the molecular dissection of the pathogenic mechanisms underlying skeletal dysplasias. Throughout the years, the genetic cause of these disorders has been extensively studied which resulted in the identification of a variety of disease-causing genes and pathways that are involved in bone formation by osteoblasts, bone resorption by osteoclasts, or both processes. Due to this rapidly increasing knowledge, the insights into the regulatory mechanisms of bone metabolism are continuously improving resulting in the identification of novel therapeutic targets for disorders with reduced bone mass and increased bone fragility.