Pattern of SQSTM1 Gene Variants in a Hungarian Cohort of Paget's Disease of Bone.

Paget's disease of bone (PDB) is characterized by focal or multifocal increase in bone turnover. One of the most well-established candidate genes for susceptibility to PDB is Sequestosome 1 (SQSTM1). Mutations in SQSTM1 have been documented among Western-European, British and American patients with PDB. However, there is no information on SQSTM1 mutation status in PDB patients from the Central- and Eastern-European regions. In this study, we conducted a mutation screening for SQSTM1 gene variants in 82 PDB patients and 100 control participants in Hungary. Mutations of SQSTM1 were detected in 18 PDB patients (21.95%); associations between genotype and clinical characteristics were also analyzed. Altogether, six different exonic alterations, including two types of UTR variants in the SQSTM1 gene, were observed in our PDB patients. Similarly, to previous genetic studies on Paget's disease, our most commonly detected variant was the c.1175C > T (p.Pro392Leu) in nine cases (four in monostotic and five in polyostotic form). We have surveyed the germline SQSTM1 variant distribution among Hungarian patients with PDB. We also highlighted that the pattern of the analyzed disease-associated pathophysiological parameters could partially discriminate PDB patients with normal or mutant SQSTM1 genotype. However, our findings also underline and strengthen that not solely SQSTM1 stands in the background of the complex PDB etiology.

Polymorphisms of CSF1 and TM7SF4 genes in a case of mild juvenile Paget's disease found using next-generation sequencing.

Juvenile Paget's disease (JPD) is a rare autosomal-recessive condition. It is diagnosed in young children and characterized by a generalized increase in bone turnover, bone pain, and skeletal deformity. Our patient was diagnosed after a pathological fracture when she was 11 years old. When we first examined her at the age of 30 she had bone pain and deformity in both the femur and tibia. Serum alkaline phosphatase (ALP) level, radiology, bone scintigraphy, and densitometry were monitored. Next generation sequencing (NGS) technology, namely semiconductor sequencing, was used to determine the genetic background of JPD. Seven target genes and regions were selected and analyzed after literature review (TM7SF4, SQSTM1, TNFRSF11A, TNFRSF11B, OPTN, CSF1, VCP). No clear pathogenic mutation was found, but we detected missense polymorphisms in CSF1 and TM7SF4 genes. After treatment with zoledronic acid, infusion bone pain and ALP level decreased. We can conclude that intravenous zoledronic acid therapy is effective and safe for suppressing bone turnover and improving symptoms in JPD, but the long-term effects on clinical outcomes are unclear. Our findings also suggest that NGS may help explore the pathogenesis and aid the diagnosis of JPD.

[Paget's disease: clinical update]. / A Paget-kór aktuális kérdései.

Paget's disease is a chronic disorder of bone remodeling, characterized by an abnormal increase of osteoclast and, hence, osteoblast activity. The imbalance of bone turnover results in the formation of unhealthy and fragile bone. It also leads to impairment of adjacent joints and to a risk of various complications. Current research focuses on the elucidation of the etiologic role viral infection and predisposing genetic factors. Paget's disease is commonly discovered by chance; its suspicion is raised either by high level of alkaline phosphatase or by the X-ray of the pathological bone. Bisphosphonates have proven to be effective in controlling disease activity because they inhibit osteoclast function. Their use is recommended when bone-derived serum alkaline phosphatase is high and/or when disease localizations are highly suspected for the development of complications.

Gene expression profiling in Paget's disease of bone: upregulation of interferon signaling pathways in pagetic monocytes and lymphocytes.

UNLABELLED: We examined the gene expression profile of genes involved in bone metabolism in 23 patients with PD compared with 23 healthy controls. We found a significant overexpression of the genes of the IFN pathway along with a downregulation of tnf-alpha. Our result suggest that IFN-mediated signaling may play important roles in aberrant osteoclastogenesis of PD. INTRODUCTION: Paget's disease of bone (PD) is characterized by focal regions of highly exaggerated bone remodeling and aberrant osteoclastogenesis. Under physiological conditions, circulating monocytes may serve as early progenitors of osteoclasts and along with peripheral blood lymphocytes produce a wide variety of factors important in bone metabolism. Nevertheless, little is known about the roles of circulating monocytes and lymphocytes in relation to the pathological bone turnover in PD. MATERIALS AND METHODS: In this study, we aimed at investigating the gene expression pattern of PD using quantitative real-time PCR in monocytes and lymphocytes isolated from peripheral blood mononuclear cells (PBMCs). Fifteen genes known to be involved in osteoclastogenesis were studied in cells from 23 patients with PD and in cells from 23 healthy controls. Eight human genes including ifn-alpha (3.48-fold, p < 0.001), ifn-beta (2.68-fold, p < 0.001), ifn-gamma (1.98-fold, p = 0.002), p38 beta2 mapk (2.47-fold, p = 0.002), ifn-gammar1 (2.03-fold, p = 0.01), ifn-gammar2 (1.81-fold, p = 0.02), stat1 (1.57-fold, p = 0.037), and tnf-alpha (-2.34, p < 0.001) were found to be significantly altered in pagetic monocytes compared with monocytes of healthy controls. RESULTS: In pagetic lymphocytes, significant changes in the expression of ifn-alpha (2.17-fold, p < 0.001), ifn-beta (2.13-fold, p = 0.005), ifn-gamma (1.89-fold, p < 0.001), ifn-gammar1 (1.02-fold, p = 0.04), ifn-gammar2 (1.01-fold, p = 0.031), stat2 (1.79-fold, p < 0.001), and tnf-alpha (-1.49, p < 0.001) were found compared with lymphocytes of healthy controls. Furthermore, IFN-gamma protein was significantly elevated in the sera of PD patients (18.7 +/- 6.69 pg/ml) compared with healthy controls (3.87 +/- 6.48 pg/ml, p = 0.042). CONCLUSIONS: In conclusion, our data suggest that novel pathways mainly related to the IFN-mediated signaling may play important roles in the aberrant osteoclastogenesis of PD.

Age- and sex-related regional compressive strength characteristics of human lumbar vertebrae in osteoporosis.

OBJECTIVE: To obtain the compressive load bearing and energy absorption capacity of lumbar vertebrae of osteoporotic elderly for the everyday medical praxis in terms of the simple diagnostic data, like computed tomography (CT), densitometry, age, and sex. METHODS: Compressive test of 54 osteoporotic cadaver vertebrae L1 and L2, 16 males and 38 females (age range 43-93, mean age 71.6 ± 13.3 years, mean bone mineral density (BMD) 0.377 ± 0.089 g/cm(2), mean T-score -5.57 ± 0.79, Z-score -4.05 ± 0.77) was investigated. Based on the load-displacement diagrams and the measured geometrical parameters of vertebral bodies, proportional, ultimate and yield stresses and strains, Young's modulus, ductility and energy absorption capacity were determined. Three vertebral regions were distinguished: superior, central and inferior regions, but certain parameters were calculated for the upper/ lower intermediate layers, as well. Cross-sectional areas, and certain bone tissue parameters were determined by image analysis of CT pictures of vertebrae. Sex- and age-related decline functions and trends of strength characteristics were determined. RESULTS: Size-corrected failure load was 15%-25% smaller in women, proportional and ultimate stresses were about 30%-35% smaller for women in any region, and 20%-25% higher in central regions for both sexes. Young's moduli were about 30% smaller in women in any region, and 20%-25% smaller in the central region for both sexes. Small strains were higher in males, large strains were higher in females, namely, proportional strains were about 25% larger in men, yield and ultimate strains were quasi equal for sexes, break strains were 10% higher in women. Ultimate energy absorption capacity was 10%-20% higher in men; the final ductile energy absorption capacity was quasi equal for sexes in all levels. Age-dependence was stronger for men, mainly in central regions (ultimate load, male: r = -0.66, p < 0.01, female: r = -0.52, p < 0.005; ultimate stress, male: r = -0.69, p < 0.01, female: r = -0.50, p < 0.005; Young's modulus, male: r = -0.55, p < 0.05, female: r = -0.52, p < 0.005, ultimate stiffness, male: r = -0.58, p < 0.05, female: r = -0.35, p < 0.03, central ultimate absorbed energy density, male: r = -0.59, p < 0.015, female: r = -0.29, p < 0.08). CONCLUSIONS: For the strongly osteoporotic population (BMD < 0.4 g/cm(2), T-score < -4) the statical variables (loads, stresses) showed significant correlation; mixed variables (stiffness, Young's modulus, energy) showed moderate correlation; kinematical variables (displacements, strains) showed no correlation with age. The strong correlation of men between BMD and aging (r = -0.82, p < 0.001) and betwen BMD and strength parameters (r = 0.8-0.9, p < 0.001) indicated linear trends in age-related strength loss for men; however, the moderate correlation of women between BMD and aging (r = -0.47, p < 0.005) and between BMD and strength parameters (r = 0.4-0.5, p < 0.005) suggested the need of nonlinear (quadratic) approximation that provided the better fit in age-related strength functions of females modelling postmenopausal disproportionalities.

Epidemiology of Paget's disease in Europe: the prevalence is decreasing.

UNLABELLED: This study estimated changes in the age- and sex-specific prevalence of Paget's disease of bone in six European towns over a 20-year period. Declines in prevalence were observed in this disorder, occurring among both men and women. INTRODUCTION: To estimate secular changes in the age-and sex-specific prevalence of Paget's disease of bone in Europe, we conducted a second radiographic survey using identical sampling and methods in six European towns where a baseline study was performed in 1978-1979. In addition to these towns, the survey was carried out in two Hungarian centers not included in the initial study. MATERIALS AND METHODS: In each center, a sample of abdominal radiographs of people >or=55 years of age was taken from stored films within the radiology department of the principal general hospital. Radiographs showing the entire pelvis, sacrum, femoral heads, and lumbar vertebrae were studied for the period of 2000-2001. The films were evaluated by a trained observer and a consultant radiologist. RESULTS: A total of 6935 radiographs (3512 women and 3423 men) were assessed in the eight towns. The overall age- and sex-standardized prevalence rate of Paget's disease was 0.3% with a male/female ratio of 1.5. Prevalence increased with age among men and women rising to 0.8% of men and 0.9% of women >/=85 years of age. The differences in prevalence rate among the European centers were relatively small, especially in women. There was a decline in rates between 1978/79 and 2000/01. CONCLUSIONS: These European data confirm the decrease in frequency of Paget's disease observed in Britain. These declines favor an environmental contribution to the causation of the disease that requires further research.

Novel UBA domain mutations of SQSTM1 in Paget's disease of bone: genotype phenotype correlation, functional analysis, and structural consequences.

UNLABELLED: Three novel missense mutations of SQSTM1 were identified in familial PDB, all affecting the UBA domain. Functional and structural analysis showed that disease severity was related to the type of mutation but was unrelated to the polyubiquitin-binding properties of the mutant UBA domain peptides. INTRODUCTION: Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1) gene have recently been identified as a common cause of familial Paget's disease of bone (PDB), but the mechanisms responsible are unclear. We identified three novel SQSTM1 mutations in PDB, conducted functional and structural analyses of all PDB-causing mutations, and studied the relationship between genotype and phenotype. MATERIALS AND METHODS: Mutation screening of the SQSTM1 gene was conducted in 70 kindreds with familial PDB. We characterized the effect of the mutations on structure of the UBA domain by protein NMR, studied the effects of the mutant UBA domains on ubiquitin binding, and looked at genotype-phenotype correlations. RESULTS AND CONCLUSIONS: Three novel missense mutations affecting the SQSTM1 UBA domain were identified, including a missense mutation at codon 411 (G411S), a missense mutation at codon 404 (M404V), and a missense mutation at codon 425 (G425R). We also identified a deletion leading to a premature stop codon at 394 (L394X). None of the mutations were found in controls. Structural analysis showed that M404V and G425R involved residues on the hydrophobic surface patch implicated in ubiquitin binding, and consistent with this, the G425R and M404V mutants abolished the ability of mutant UBA domains to bind polyubiquitin chains. In contrast, the G411S and P392L mutants bound polyubiquitin chains normally. Genotype-phenotype analysis showed that patients with truncating mutations had more extensive PDB than those with missense mutations (bones involved = 6.05 +/- 2.71 versus 3.45 +/- 2.46; p < 0.0001). This work confirms the importance of UBA domain mutations of SQSTM1 as a cause of PDB but shows that there is no correlation between the ubiquitin-binding properties of the different mutant UBA domains and disease occurrence or extent. This indicates that the mechanism of action most probably involves an interaction between SQSTM1 and a hitherto unidentified protein that modulates bone turnover.

Atypical form of active melorheostosis and its treatment with bisphosphonate.

We present the case of a 38-year-old man in whom extensive bilateral melorheostosis was associated with elevated serum alkaline phosphatase, swelling of the right foot and progressive deformity of the left hand, left leg and right foot. Radiography, computed tomography and bone scintigraphy were performed. Following treatment with bisphosphonate (30 mg/day of pamidronate for 6 days) infusion, the pain and swelling of his right foot showed improvement and his elevated serum alkaline phosphatase decreased.