The diagnosis and management of patients with idiopathic osteolysis

The role of genetic and epigenetic factors in determining the risk of spinal fragility fractures: new insights in the management of spinal osteoporosis

Osteoporosis predisposes patients to spinal fragility fractures. Imaging plays a key role in the diagnosis and prognostication of these osteoporotic vertebral fractures (OVF). However, the current imaging knowledge base for OVF is lacking sufficient standardisation to enable effective risk prognostication. OVF have been shown to be more prevalent in Caucasian patient cohorts in comparison to the Eastern Asian population. These population-based differences in risk for developing OVF suggest that there could be genetic and epigenetic factors that drive the pathogenesis of osteoporosis, low bone mineral density (BMD) and OVF. Several genetic loci have been associated with a higher vertebral fracture risk, although at varying degrees of significance. The present challenge is clarifying whether these associations are specific to vertebral fractures or osteoporosis more generally. Furthermore, these factors could be exploited for diagnostic interpretation as biomarkers [including novel long non-coding (lnc)RNAs, micro (mi)RNAs and circular (circ)RNAs]. The extent of methylation of genes, alongside post-translational histone modifications, have shown to affect several interlinked pathways that converge on the regulation of bone deposition and resorption, partially through their influence on osteoblast and osteoclast differentiation. Lastly, in addition to biomarkers, several exciting new imaging modalities could add to the established dual-energy X-ray absorptiometry (DXA) method used for BMD assessment. New technologies, and novel sequences within existing imaging modalities, may be able to quantify the quality of bone in addition to the BMD and bone structure; these are making progress through various stages of development from the pre-clinical sphere through to deployment in the clinical setting. In this mini review, we explore the literature to clarify the genetic and epigenetic factors associated with spinal fragility fractures and delineate the causal genes, pathways and interactions which could drive different risk profiles. We also outline the cutting-edge imaging modalities which could transform diagnostic protocols for OVF.

A novel gene mutation for multicentric osteolysis nodulosis and arthropathy: Case report and review of literature

Frank-Ter Haar syndrome (FTHS), Winchester syndrome (WS), Torg syndrome (TS) and Multicentric Osteolysis Nodulosis and Arthropathy (MONA) are progressive skeletal dysplasia consisting of acro-osteolysis. Mutation in Matrix Metalloproteinase 2 (MMP2), Matrix Metalloproteinase 14 (MMP14) and SH3PXD2B are known genetic defects in these disorders. We hereby report a 5 years and 9 months old girl suffering from progressive limb deformity. She is the first child of a relative couple, who was referred to metabolic disorders' clinic due to poor growth and bone pain. On physical examination, minor facial dysmorphism, hypertrichosis, severe hand deformity with limitation in range of motion in carpal, metacarpal and phalangeal joints, hallux valgus deformity of feet, soft tissue hypertrophy and nodule formation in palmoplantar areas were detected. Her past history indicated a cardiac defect resulting in open heart surgery at 8 months of age. Genetic study revealed a new homozygote nonsense mutation in MMP2 gene explaining her clinical manifestations. We recommend careful evaluation and follow-up of patients with congenital heart disease, as it may be the first presentation of a genetic multisystem disorder. Early differentiation of the disease from other skeletal dysplasia and rheumatologic disorders could prevent unnecessary management.

Multicentric Osteolysis, Nodulosis, and Arthropathy in two unrelated children with matrix metalloproteinase 2 variants: Genetic-skeletal correlations

Multicentric Osteolysis, Nodulosis, and Arthropathy (MONA) syndrome is a rare genetic skeletal dysplasia. Its diagnosis can be deceptively similar to childhood-onset genetic skeletal dysplasias and juvenile idiopathic arthritis. We aimed to report the syndrome’s clinical and radiologic features with emphasis on skeletal manifestations. And establish relevant phenotype-genotype correlations. We evaluated two boys, 4-and-7-years-old with MONA syndrome. Both patients had consanguineous parents. We verified the diagnosis by correlating the outcomes of clinical, radiologic and molecular analysis. We specifically evaluated the craniofacial morphology and clinical and radiographic skeletal abnormalities. We contextualized the resultant phenotype-genotype correlations to publications on MONA and its differential diagnosis. Skeletal manifestations were the presenting symptoms and mostly restricted to hands and feet in terms of fixed extension deformity of the metacarpophalangeal and flexion deformity of the interphalangeal joints with extension deformity of big toes. There were arthritic symptoms in the older patient especially of the wrists and minute pathologic fractures. The skeletal radiographs showed osteopenia/dysplastic changes of hands and feet. Both patients had variants in the matrix metalloproteinase2 gene which conformed to phenotype of previously reported literature in one patient while the other had a novel variant which conformed to MONA phenotype. Craniofacial abnormalities were present. However, minimal extra-skeletal manifestations. Overall, there is an emerging distinctive skeletal pattern of involvement in terms of both clinical and radiographic features. This includes age of onset and location of presenting skeletal manifestations, chronological order of joint affection, longitudinal disease progression, specifics of skeletal radiographic pathology and craniofacial features. Nevertheless, physicians are cautioned against differential diagnosis of similar genetic skeletal dysplasias and juvenile idiopathic arthritis.

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Presenting manifestations erupt simultaneously in the hands and feet.

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Skeletal manifestations proceed fairly rapidly in a distal-to-proximal fashion.

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Radiographic features are a mixture of osteopenia, joint destruction and fractures.

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Major disability may ensue in late childhood/adolescence, arthrogenic dysplasia

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Non-skeletal manifestations are variable in terms of age of appearance and frequency

Multicentric osteolytic syndromes represent a phenotypic spectrum defined by defective collagen remodeling

Frank-Ter Haar syndrome (FTHS), Winchester syndrome (WS), and multicentric osteolysis, nodulosis, and arthropathy (MONA) are ultra-rare multisystem disorders characterized by craniofacial malformations, reduced bone density, skeletal and cardiac anomalies, and dermal fibrosis. These autosomal recessive syndromes are caused by homozygous mutation or deletion of respectively SH3PXD2B (SH3 and PX Domains 2B), MMP14 (matrix metalloproteinase 14), or MMP2. Here, we give an overview of the clinical features of 63 previously reported patients with an SH3PXD2B, MMP14, or MMP2 mutation, demonstrating considerable clinical overlap between FTHS, WS, and MONA. Interestingly, the protein products of SH3PXD2B, MMP14, and MMP2 directly cooperate in collagen remodeling. We review animal models for these three disorders that accurately reflect the major clinical features and likewise show significant phenotypical similarity with each other. Furthermore, they demonstrate that defective collagen remodeling is central in the underlying pathology. As such, we propose a nosological revision, placing these SH3PXD2B, MMP14, and MMP2 related syndromes in a novel "defective collagen-remodelling spectrum (DECORS)". In our opinion, this revised nosology better reflects the central role for impaired collagen remodeling, a potential target for pharmaceutical intervention.

XRK3F2 Inhibition of p62-ZZ Domain Signaling Rescues Myeloma-Induced GFI1-Driven Epigenetic Repression of the Runx2 Gene in Pre-osteoblasts to Overcome Differentiation Suppression

Multiple myeloma bone disease (MMBD) is characterized by non-healing lytic bone lesions that persist even after a patient has achieved a hematologic remission. We previously reported that p62 (sequestosome-1) in bone marrow stromal cells (BMSC) is critical for the formation of MM-induced signaling complexes that mediate OB suppression. Importantly, XRK3F2, an inhibitor of the p62-ZZ domain, blunted MM-induced Runx2 suppression in vitro, and induced new bone formation and remodeling in the presence of tumor in vivo. Additionally, we reported that MM cells induce the formation of repressive chromatin on the Runx2 gene in BMSC via direct binding of the transcriptional repressor GFI1, which recruits the histone modifiers, histone deacetylase 1 (HDAC1) and Enhancer of zeste homolog 2 (EZH2). In this study we investigated the mechanism by which blocking p62-ZZ domain-dependent signaling prevents MM-induced suppression of Runx2 in BMSC. XRK3F2 prevented MM-induced upregulation of Gfi1 and repression of the Runx2 gene when present in MM-preOB co-cultures. We also show that p62-ZZ-domain blocking by XRK3F2 also prevented MM conditioned media and TNF plus IL7-mediated Gfi1 mRNA upregulation and the concomitant Runx2 repression, indicating that XRK3F2's prevention of p62-ZZ domain signaling within preOB is involved in the response. Chromatin immunoprecipitation (ChIP) analyses revealed that XRK3F2 decreased MM-induced GFI1 occupancy at the Runx2-P1 promoter and prevented recruitment of HDAC1, thus preserving the transcriptionally permissive chromatin mark H3K9ac on Runx2 and allowing osteogenic differentiation. Furthermore, treatment of MM-exposed preOB with XRK3F2 after MM removal decreased GFI1 enrichment at Runx2-P1 and rescued MM-induced suppression of Runx2 mRNA and its downstream osteogenic gene targets together with increased osteogenic differentiation. Further, primary BMSC (hBMSC) from MM patients (MM-hBMSC) had little ability to increase H3K9ac on the Runx2 promoter in osteogenic conditions when compared to hBMSC from healthy donors (HD). XRK3F2 treatment enriched Runx2 gene H3K9ac levels in MM-hBMSC to the level observed in HD-hBMSC, but did not alter HD-hBMSC H3K9ac. Importantly, XRK3F2 treatment of long-term MM-hBMSC cultures rescued osteogenic differentiation and mineralization. Our data show that blocking p62-ZZ domain-dependent signaling with XRK3F2 can reverse epigenetic-based mechanisms of MM-induced Runx2 suppression and promote osteogenic differentiation.

Bisphosphonates in multicentric osteolysis, nodulosis and arthropathy (MONA) spectrum disorder - an alternative therapeutic approach

Multicentric osteolysis, nodulosis and arthropathy (MONA) spectrum disorder is a rare inherited progressive skeletal disorder caused by mutations in the matrix metalloproteinase 2 (MMP2) gene. Treatment options are limited. Herein we present successful bisphosphonate therapy in three affected patients. Patients were treated with bisphosphonates (either pamidronate or zoledronate) for different time periods. The following outcome variables were assessed: skeletal pain, range of motion, bone densitometry, internal medical problems as well as neurocognitive function. Skeletal pain was dramatically reduced in all patients soon after initiation of therapy and bone mineral density increased. Range of motion did not significantly improve. One patient is still able to walk with aids at the age of 14 years. Neurocognitive development was normal in all patients. Bisphosphonate therapy was effective especially in controlling skeletal pain in MONA spectrum disorder. Early initiation of treatment seems to be particularly important in order to achieve the best possible outcome.

Gorham-Stout syndrome of the shoulder

Introduction: Gorham-Stout syndrome (GSS) is a rare but severe subtype of idiopathic osteolysis. There are no guidelines for the treatment of GSS. We analysed different diagnostic and therapeutic regimes and we describe the sucessful treatment of GSS considering individual patient factors.

Methods: We diagnosed three patients with shoulder-specific GSS using clinical, radiological and histopathological examinations. Two out of three patients with similar clinical appearances were treated non-operatively. One patient was treated by reverse shoulder arthroplasty. All patients were analysed retrospectively using clinical and radiological evaluation with a mean follow-up of 42 (range 30–50) months.

Results: Two patients had few symptoms of GSS and were treated conservatively. One patient underwent arthroplasty, with a good clinical result. No additional therapy, such as radiation or anti-resorptive medications, was needed for the stable fixation of the prosthesis and the termination of osteolysis. In all patients we found good clinical outcomes with high patient satisfaction.

Discussion: GSS is diagnosed after exclusion of infectious, malignant, and systemic disorders. The diagnosis should be supported by clinical, radiological, and histopathological characteristics of patients. Different humoral and cellular changes have been reported in GSS, but lack sufficient supporting evidence. GSS is associated with angiomatous and lymphatic malformations. The changes in GSS and the theories of its pathophysiology may reveal.

[Multicentric carpotarsal osteolysis in a rheumatologist's practice]

Multicentric carpotarsal osteolysis (MCTO) syndrome is a rare skeletal dysplasia associated with missense mutation in the MAFB gene, usually manifesting in young childhood, and showing variative phenotypic signs and course. The clinical manifestations of the syndrome include aggressive osteolysis predominantly of carpal and tarsal bones, progressive nephropathy, and mild craniofacial anomalies. The similarity between the initial clinical manifestations of MCTO and the symptoms of childhood inflammatory joint diseases makes a diagnosis very difficult, in the early stages of the disease in particular, and frequently leads to the ungrounded use of long-term immunosuppressive therapy. The paper describes a familial case of MCTO without affecting the kidneys in the mother and daughter.

Complex single step skull reconstruction in Gorham's disease - a technical report and review of the literature

Background

Gorham’s disease is a rare osteolytic disorder characterized by progressive resorption of bone and replacement of osseous matrix by a proliferative non-neoplastic vascular or lymphatic tissue. A standardized treatment protocol has not yet been defined due to the unpredictable natural history of the disease and variable clinical presentations. No single treatment has proven to be superior in arresting the course of the disease. Trials have included surgery, radiation and medical therapies using drugs such as calcium salts, vitamin D supplements and hormones. We report on our advantageous experience in the management of this osteolyic disorder in a case when it affected only the skull vault. A brief review of pertinent literature about Gorham’s disease with skull involvement is provided.

Case presentation

A 25-year-old Caucasian male presented with a skull depression over the left fronto-temporal region. He noticed progressive enlargement of the skull defect associated with local pain and mild headache. Physical examination revealed a tender palpable depression of the fronto-temporal convexity. Conventional X-ray of the skull showed widespread loss of bone substance. Subsequent CT scans showed features of patchy erosions indicative of an underlying osteolysis. MRI also revealed marginal enhancement at the site of the defect. The patient was in need of a pathological diagnosis as well as complex reconstruction of the afflicted area. A density graded CT scan was done to determine the variable degrees of osteolysis and a custom made allograft was designed for cranioplasty preoperatively to allow for a single step excisional craniectomy with synchronous skull repair. Gorham’s disease was diagnosed based on histopathological examination. No neurological deficit or wound complications were reported postoperatively. Over a two-year follow up period, the patient had no evidence of local recurrence or other systemic involvement.

Conclusions

A single step excisional craniectomy and cranioplasty can be an effective treatment for patients with Gorham’s disease affecting the skull vault only. Preoperative planning by a density graded CT aids to design a synthetic bone flap and is beneficial in skull reconstruction. Systemic involvement is variable in this patient’s population.

Thoracic osteotomy for Gorham-Stout disease of the spine: a case report and literature review

INTRODUCTION

Gorham-Stout syndrome is an aggressive, non-heritable skeletal disease characterized by osteolysis following minor trauma. The primary involvement of the spine is less common (10 %) and has been described in only about 20 cases; there is no consensus about the best way to treat this condition.

PURPOSE OF THE STUDY

To report a case of Gorham-Stout syndrome involving the thoracic spine and to review the literature to suggest a post-operative treatment to prevent osteolysis.

CASE REPORT

A thirty-year-old female patient was admitted to the unit in March 2013 for a pathologic T4 fracture. X-rays and CT scan revealed the onset of T4 osteolysis and an increase in thoracic kyphosis (the local kyphosis was up to 100°). We performed surgery by posterior approach, combining posterior fixation with screws and rods from T3 to T9, decompression and vertebral osteotomy of 65°. The immediate outcome of surgery was good and the patient returned home after 24 days. At 6 and 12 months of follow-up, the patient was walking normally with no neurological sequelae.

CONCLUSION

We report a case of Gorham-Stout syndrome involving the thoracic spine that was successfully treated by interpedicular osteotomy associated with a 6 month follow-up. We suggest that this strategy can provide good results, because after fusion, the disease process remains stable. Because of the lack of cases reported, surgeons must be careful when using multiple treatments, because these treatments have many side effects.

LEVEL OF EVIDENCE

Level IV case report.

Lymphangiomatosis: clinical overview

"Lymphangiomatosis" is a general term for excessive growth of aberrant lymphatic vessels. The impact of lymphangiomatosis can be devastating due to osteolysis and/or multi-organ involvement. The disorders are heterogeneous, and treatment is dependent upon disease location and symptoms. Most reports are single cases or small case series, predominantly in the orthopedic and radiologic literature. Basic research focused on lymphatic disorders may translate into new therapies for these disorders.