Clinical and biochemical response of TNFRSF11A-mediated early-onset familial Paget disease to bisphosphonate therapy.

Early-onset familial Paget disease of bone (EoPDB) is a rare condition caused by a 27-bp insertion mutation affecting the signal peptide of TNFRSF11A, which encodes RANK. EoPDB shows phenotypic overlap to both familial expansile osteolysis and expansile skeletal hyperphosphatasia, which are caused by similar mutations in TNFRSF11A. Although EoPDB is characterized by elevated bone turnover, there is no published information on the response of this condition to antiresorptive therapy. Here, we describe the clinical and biochemical response to bisphosphonate therapy in three patients with EoPDB. In all cases, treatment with the first-generation bisphosphonate etidronate at high doses reduced biochemical markers of bone turnover but the response was incomplete and short-lived. In contrast, treatment with aminobisphosphonates resulted in greater suppression of biochemical markers of bone turnover with an extended duration of response. From a clinical perspective, the results were less impressive and there was no clear benefit from antiresorptive treatment in terms of bone deformity, deafness, and tooth loss, although bone pain improved in one patient. We conclude that intravenous aminobisphosphonate therapy may be the preferred mode of treatment for EoPDB to provide long-term suppression of bone turnover. The long-term clinical effects of treatment on the natural history of the bone disease remain uncertain however, and this will require further study.

Guidelines for diagnosis and management of Paget's disease of bone in Japan.

We here propose guidelines for the diagnosis and management of Paget's disease of bone (PDB) in Japan. These guidelines provide basic information on the epidemiology, pathophysiology, clinical signs and symptoms, diagnosis, indications for treatment, and available therapy, including orthopedic surgery. PDB is a chronic disorder characterized by focal abnormalities of bone turnover. The characteristic feature of PDB is excessive osteoclastic bone resorption coupled to increased and disorganized bone formation. The most common symptom of PDB is pain in involved bones. The most serious complication of PDB is malignant bone or soft-tissue tumor. PDB is uncommon in Japan; our survey in 2003 found 169 patients with PDB. The prevalence of PDB in Japan is 0.15/100 000; in patients aged 55 years or more, the proportion reaches 0.41/100 000. A careful medical history and physical examination are essential for the diagnosis. The diagnosis of PDB is based on finding the typical features on radiographs. Bone scintigraphy and measurement of serum alkaline phosphatase are sensitive means of screening for PDB. Since PDB is a rare disease in Japan, bone biopsy is quite often used to exclude bone metastases. The only evidence-based indication for treatment of PDB is pain in involved bones. In Japan, etidronate and calcitonin are approved by the Ministry of Health, Labour and Welfare for treating PDB, but currently risedronate is also under development for treating PDB in Japan. Indications for surgical intervention in PDB include unstable fractures, osteoarthritis, malignant soft-tissue tumor, osteosarcoma, and bone deformity.

Prevalence and clinical features of Paget's disease of bone in Japan.

The present study aimed to evaluate the prevalence and clinical presentation of Paget's disease of bone (PDB) in Japan. As PDB is a very rare disease in Japan, a nationwide mail survey was conducted targeting doctors in the specialty most frequently diagnosing and treating PDB patients in Japan. First, the literature for all case reports in Japan published between January 1990 and December 2002 was reviewed to determine who was diagnosing and treating PDB in Japan. This literature review for all case reports in Japan revealed that 72.1% of cases in Japan were reported from departments of orthopedic surgery. A nationwide two-phase mail survey was conducted for the departments of orthopedic surgery of 2,320 general hospitals accredited by the Japanese Orthopaedic Association. Phase 1 involved determining how many patients with PDB were followed at each hospital. If the answer was one or more, phase 2 of the survey gathered information on the clinical presentation of current patients. The mail survey yielded a final response rate of 75.4% for phase 1 and 87.6% for phase 2. Phase 1 indicated that the prevalence of PDB in Japan is about 2.8 cases per million capita. Phase 2 revealed a slight female predominance, lower frequency of familial clustering, higher frequency of femoral fracture in the affected femur, and a higher ratio of symptomatic PDB in Japan compared with findings in countries displaying a higher prevalence of PDB. The present epidemiological study revealed that the disorder is extremely rare in Japanese individuals, and that some differences exist with regard to the clinical features of PDB between Japanese patients and patients from high-prevalence countries.

Effect and safety of intermittent weekly administration of human parathyroid hormone 1-34 in patients with primary osteoporosis evaluated by histomorphometry and microstructural analysis of iliac trabecular bone before and after 1 year of treatment.

In order to evaluate the efficacy and safety of intermittent subcutaneous administration of 1-34 N-terminal peptide of human parathyroid hormone (hPTH 1-34), 100 units of hPTH 1-34 was subcutaneously injected once a week for 1 year in ten patients with primary osteoporsis (one male and nine females) with no qualitative abnormality of the bone according to the results of iliac crest biopsy performed previously, followed by a second biopsy after the end of the 1-year administration. Written consent of the patients for participation in the study was obtained. The mean lumbar bone mineral density (LBMD) definitely increased, by 1.8%, 3.4%, and 4.6% after 12, 24, and 48 weeks of hPTH administration, in accordance with previous clinical studies. Histomorphometric analysis after double-tetracycline labeling was completed in six patients (one male and five females) after the exclusion of those who dropped out because of adverse events unrelated to the test drug, or refusal of continuation. Examination of thin hard-tissue sections revealed no qualitative abnormalities of bone tissue or bone marrow cavity, such as osteomalacia, woven bone, or osteitis fibrosa, precluding the contribution of qualitatively abnormal tissue elements to any changes of LBMD in response to hPTH 1-34 administration. Histomorphometric measurement in the second biopsy revealed a tendency for an increase of bone volume, a significant increase of osteoid surface, and a tendency for an increase in other parameters of bone formation, compared with values obtained in the preadministration biopsy. Indices of two-dimensional microstructure obtained by microfocus computed tomography (CT) and results of node-strut analysis indicated improvement of trabecular continuity. In five patients in whom three-dimensional reconstruction images were analyzed, there were significant increases of bone volume and trabecular thickness, and a significant decrease in the trabecular bone pattern factor, a parameter related to the continuity, suggesting an improvement of the three-dimensional trabcular microstructure. Intermittent weekly subcutaneous injections of hPTH (1-34) for 48 weeks increased trabecular bone volume and improved microstructure, without causing the appearance of abnormal bone elements in primary osteoporosis.

Significance of serum CrossLaps as a predictor of changes in bone mineral density during estrogen replacement therapy; comparison with serum carboxyterminal telopeptide of type I collagen and urinary deoxypyridinoline.

The newly developed Elecsys Beta-CrossLaps/serum assay measures C-terminal telopeptide of type I collagen and has thus been proposed as a reliable serum marker for bone resorption. We investigated its usefulness for monitoring the therapeutic effect of estrogen replacement therapy on bone turnover and bone mineral density (BMD) in patients with postmenopausal osteoporosis. Serum Beta-CTx decreased by 43.2% +/- 9.2% (mean +/- SD), and 55.1% +/- 7.0% at 3 and 6 months, respectively, after initiation of estrogen replacement therapy (ERT), which was significantly greater than the respective value of urinary excretion of deoxypyridinoline (DPD) (27.8% +/- 4.1%, 34.1% +/- 4.9%, respectively) or pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) assay (14.5% +/- 4.1%, 13.1% +/- 5.0%, respectively). The percent reduction in serum Beta-CTx at 1, 3, and 6 months after initiation of ERT was significantly correlated in a negative manner with the percent increase in spinal BMD at 6 months. Further, ROC analysis to determine the significance of the percent change in bone resorption markers after 3 months of ERT in predicting the gain in spine BMD after 6 months suggested that serum Beta-CTx and urinary DPD might provide a more discriminating indicator than serum ICTP. In conclusion, the findings suggest that the Elecsys Beta-CrossLaps/serum assay provides a sensitive, and thus useful, tool for assessing bone resorption state in Japanese patients.

Technical and clinical characterization of the Bio-PTH (1-84) immunochemiluminometric assay and comparison with a second-generation assay for parathyroid hormone.

BACKGROUND: The Bio-Intact parathyroid hormone (1-84) assay (Bio-PTH), a newly developed two-site immunochemiluminometric assay, measures exclusively PTH (1-84) in contrast to second-generation "intact PTH" (I-PTH) assays. We investigated the technical performance and clinical significance of this new assay. METHODS: PTH was measured simultaneously by the Bio-PTH assay and Allegro intact PTH IRMA in sera from Japanese patients with calcium disorders. RESULTS: Measured Bio-PTH in serum was unaffected by six freeze-thaw cycles and was stable at 4 degrees C for 7 days and during storage at -20 or -80 degrees C over 28 days. The calibration curve was linear to 1800 ng/L. The detection limit was 3.9 ng/L. The intra- and interassay imprecision was <2.8% and 3.5%, respectively, for analyte concentrations spanning the range of the calibration curve. Bio-PTH was unaffected by a 1000-fold excess of PTH (7-84), although I-PTH reacted equally with PTH (7-84) and PTH (1-84). Bio-PTH was correlated with I-PTH in healthy individuals (r = 0.953; P <0.0001; n = 26) and in the full population without renal dysfunction (r = 0.994; P <0.0001; n = 62). In 72 volunteers, mean (SD) Bio-PTH was 22.2 (7.1) ng/L, or 62% of the mean I-PTH [36.1 (22.3) ng/L]. This ratio was 51% in hemodialysis patients (n = 177). Mean Bio-PTH was high in patients with primary hyperparathyroidism [121 (85) ng/L; n = 18] and hemodialysis patients [102 (104) ng/L; n = 177], low in idiopathic hypoparathyroidism [5.5 (2.8) ng/L; n = 4], and within 2 SD of the mean for healthy controls in Paget disease of the bone [34 (15) ng/L; n = 9] and bone metastasis [24 (12) ng/L; n = 8]. CONCLUSION: The Bio-PTH assay is sensitive and precise and produces expected results for patients with the studied disorders of calcium metabolism.

Phenotypic characterization of early onset Paget's disease of bone caused by a 27-bp duplication in the TNFRSF11A gene.

Three different insertion mutations in the TNFRSF11A gene affecting the signal peptide of RANK have been described. An 18-bp duplication at position 84 (84dup18) is associated with the clinical syndrome of familial expansile osteolysis (FEO), whereas a 15-bp duplication at the same site (84dup15) causes the syndrome of expansile skeletal hyperphosphatasia (ESH). Here we report the phenotype of patients harboring a 27-bp duplication at position 75 (75dup27) in RANK. Affected individuals had hearing impairment and tooth loss beginning in the second or third decade. Radiographs of affected bones showed lytic and sclerotic lesions with bony enlargement and deformity. Serum alkaline phosphatase levels were elevated between 2 and 17 times above the normal range. Most patients had pelvic and skull involvement, and all had involvement of the mandible and maxilla. Most patients also had bony enlargement of the small joints of the hands, and one developed hypercalcemia during a period of immobilization. We conclude that the 75dup27 mutation of RANK causes a Paget's disease of bone-like phenotype that is distinct from, but which overlaps with, FEO and ESH. A particularly striking feature was involvement of the mandible and maxilla, but it remains to be seen if this is a specific feature of the 75dup27 mutation until further kindreds with this mutation are reported.

[Development of bisphosphonates].

Bisphosphonates (BPs), antiresorptive agents, have been established as first line drugs for treatment of osteoporosis and widely used all over the worlds. In Japan alendronate and risedronate, newer generation of BPs have been developed according to a evidence-based guideline and approved for clinical use in 2001 and in 2002, respectively. Although these BPs have been shown to have antifractures efficacy, great efforts have been made to explore convenient administration routes and schedules of BPs for individual patients. On the other hand, some of BPs are indicated for abnormal bone and calcium metabolism other than osteoporosis, including Paget's disease of bone, hypercalcemia associated with malignancy. Currently, extended indications of BPs are under development to the treatments of metastatic bone diseases, such as breast cancer, multiple myeloma, and rheumatoid arthritis. Since etidronate, first generation of BP also have the inhibitory effects on mineralization and hydroxyapatite crystal formation, application of this agent to ectopic ossification and calcification are very promising and under investigation.