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The current study evaluated the efficacy and safety of a denosumab biosimilar, QL1206 (60 mg), compared to placebo in postmenopausal Chinese women with osteoporosis and high fracture risk. At 31 study centers in China, a total of 455 postmenopausal women with osteoporosis and high fracture risk were randomly assigned to receive QL1206 (60 mg subcutaneously every 6 months) or placebo. From baseline to the 12-month follow-up, the participants who received QL1206 showed significantly increased bone mineral density (BMD) values (mean difference and 95% CI) in the lumbar spine: 4.780% (3.880%, 5.681%), total hip :3.930% (3.136%, 4.725%), femoral neck 2.733% (1.877%, 3.589%) and trochanter: 4.058% (2.791%, 5.325%) compared with the participants who received the placebo. In addition, QL1206 injection significantly decreased the serum levels of C-terminal crosslinked telopeptides of type 1 collagen (CTX): -77.352% (-87.080%, -66.844%), and N-terminal procollagen of type l collagen (P1NP): -50.867% (-57.184%, -45.217%) compared with the placebo over the period from baseline to 12 months. No new or unexpected adverse events were observed. We concluded that compared with placebo, QL1206 effectively increased the BMD of the lumbar spine, total hip, femoral neck and trochanter in postmenopausal Chinese women with osteoporosis and rapidly decreased bone turnover markers. This study demonstrated that QL1206 has beneficial effects on postmenopausal Chinese women with osteoporosis and high fracture risk.

Purpose. GWAS has successfully located and analyzed the pathogenic genes of osteoporosis. Genetic studies have found that heritability of BMD is 50%–85% while the other half is caused by hip geometric parameters and tissue horizontal characteristics. This study was designed to study the GWAS of osteoporosis in Shanghai Han population. Methods. We collected 1224 unrelated healthy young men (20–40 years old), young women (20–40 years old), and postmenopausal women (over 50 years old) who lived in Shanghai. BMD and hip geometric parameters were measured by dual-energy X-ray absorptiometry. The genomic DNA of peripheral blood was extracted and analyzed by using Illumina Human Asian Screening Array-24 + v 1.0 (ASA) gene chip. Statistical analysis was carried out to evaluate the relationship between these SNPs and BMD and hip geometric parameters. Results. A total of 1155 subjects were included. We found that one SNP rs35282355 located in the human immunodeficiency virus type 1 enhancer-binding protein 3 gene (HIVEP3) and another 25 SNPs located in LINC RNA were significantly correlated with bone mineral content (BMC) in the femoral neck ( P = 2.30 × 10−9, P P = 5.95 × 10−8). Conclusions. Through this study, we found that HIVEP3 gene and LINC RNA are potentially correlated with femoral neck BMC. These results provide important information for us to further understand the etiology and genetic pathogenesis of osteoporosis. In the future, we will expand the sample size to verify these loci and carry out molecular research.

Purposes: In order to investigate the association between serum periostin levels and the variation of its encoding gene POSTN and the prevalence of vertebral fractures and bone mineral density (BMD) in Chinese postmenopausal women, an association study was performed. Materials and Methods: 385 postmenopausal women were recruited. For participants without a history of vertebral fracture, lateral X-rays of the spine covering the fourth thoracic spine to the fifth lumbar spine were performed to detect any asymptomatic vertebral fractures. Ten tag-single nucleotide polymorphisms (SNP) of POSTN were genotyped. Serum periostin levels, biochemical parameters, and BMD were measured individually. Results: rs9603226 was significantly associated with vertebral fractures. Compared to allele G, the minor allele A carriers of rs9603226 had a 1.722-fold higher prevalence of vertebral fracture (p = 0.037). rs3923854 was significantly associated with the serum periostin level. G/G genotype of rs3923854 had a higher serum periostin level than C/C and C/G (67.26 ± 19.90 ng/mL vs. 54.57 ± 21.44 ng/mL and 54.34 ± 18.23 ng/mL). Furthermore, there was a negative correlation between the serum level of periostin and BMD at trochanter and total hip. Conclusion: Our study suggested that genetic variation of POSTN could be a predicting factor for the risk of vertebral fractures. The serum level of periostin could be a potential biochemical parameter for osteoporosis in Chinese postmenopausal women.

We sought to characterize the phenotypes and identify the SEC24D gene mutations associated with Chinese families of osteogenesis imperfecta (OI). Using whole-exome sequencing, we discovered two novel compound SEC24D mutations of OI patients. Our study extended both the phenotypic and the genotype of the OI patients with SEC24D mutations. To date, only three compound heterozygous mutations in the SEC24D gene have been found to cause recessively inherited forms of OI. We sought to characterize the phenotypes and to identify the SEC24D gene mutations associated with Chinese families with OI. Using whole-exome sequencing in two probands, we identified two novel compound heterozygous mutations in SEC24D. In family 1, the proband was a 23-year-old male; he had recurrent fractures and dentinogenesis imperfecta. His anterior fontanel was not closed, and he showed facial dysmorphism. A computed tomography three-dimensional imaging of the cranium showed skull deformities associated with a broad ossification defect in the frontoapical area, a widened sagittal suture, and Wormian bones. In family 2, the proband was a 7-year-old boy, who also had recurrent fractures and dentinogenesis imperfecta. His anterior fontanel was not closed, and he did not have obvious facial dysmorphism. We identified one novel compound heterozygous missense substitution in the proband in family 1, including c.2723G>A (p. Cys908Tyr) and c.2842T>C (p. Ser948Pro). In the proband in family 2, we identified another novel compound heterozygous missense substitution, including c.938G>A (p. Arg313His) and c.875C>T (p. Pro292Leu). We discovered two novel compound SEC24D mutations of autosomal recessive OI patients. Our study extended both the phenotypic and the genotypic spectrum of the autosomal recessive OI patients with SEC24D mutations.

Purpose: We aimed to investigate the status of serum 25-hydroxyvitamin D [25(OH)D] among Chinese postmenopausal women in a multicenter cross-sectional study.Methods: Non-institutionalized postmenopausal women aged ≥55 years were recruited from urban and rural areas in 7 geographically different regions in China. Subject enrollment was executed during the summer and the winter. Vitamin D insufficiency and deficiency were defined as 25(OH)D < 30 and< 20 ng/ml, and was measured by liquid chromatography-tandem mass spectrometry. Women were referred to a dual-energy x-ray absorptiometry (DXA) if they had a medium-to-high fracture risk suggested by Osteoporosis Self-Assessment Tool for Asians (OSTA).Results: Among all subjects, 91.2% (1,535/1,684, 95%CI: 89.7, 92.5) had vitamin D insufficiency and 61.3% had vitamin D deficiency (1,033/1,684, 95%CI: 59.0, 63.7). The prevalence of vitamin D deficiency was significantly higher in urban dwellers (64.9 vs. 57.7% in rural, P = 0.002) and in winter-enrolled subjects (84.7 vs. 41.3% in summer, P < 0.0001). The prevalence of vitamin D inadequacy did not increase in trend by latitude and was numerically lower in women who had high fracture risk and osteoporosis. A non-curvilinear change of intact parathyroid hormone (iPTH) levels was observed at 25(OH)D >16.78 ng/mL.Conclusions: The prevalence of vitamin D inadequacy was remarkable among Chinese postmenopausal women and independent of fracture risk assessed by OSTA or osteoporosis suggested by DXA. Winter season, urban residence, however not latitude, were significantly associated with a higher likelihood of vitamin D deficiency. Optimal vitamin D status for iPTH and bone-related outcomes merits further investigation in this population.

Fibroblast growth factor 21 (FGF21) is a member of the endocrine FGF subfamily and an important metabolic regulator that has multiple beneficial effects on glucose homeostasis and lipid metabolism. However, it was unclear whether FGF21 would induce bone defects in humans. This study evaluated the associations of FGF21 levels, bone mineral density (BMD), osteoporotic fracture, and bone turnover marks (BTMs) in postmenopausal women. A total of 1342 postmenopausal Chinese Han women (511 cases of fragility fracture in the case group and 831 cases in nonfragility fracture group) were enrolled. Serum FGF21 concentration was measured by ELISA (Quantikine), serum calcium (Ca), phosphate (P), alkaline phosphatase, 25-hydroxyvitamin D, parathyroid hormone, β-crosslinked C-telopeptide of type l collagen, were measured using an automated Roche electro-chemiluminescence system. BMD was measured using dual-energy X-ray absorptiometry. The association with age, BMD, 25-hydroxyvitamin D, parathyroid hormone, β-crosslinked C-telopeptide of type l collagen, and FGF21 levels were also evaluated in postmenopausal women. In nonfracture group and fragility fracture group, postmenopausal women's FGF21 level was 226.57pg/mL (149.11-354.43 pg/mL) and 219.43pg/mL (147.21-323.74 pg/mL), respectively. There is no significant difference in serum FGF21 levels between the fragility fracture group and the nonfracture group (p = 0.160). There was a significant statistical difference in BMD between the fragility fracture group and the nonfracture group (p = 0.000). In multiple linear regression analysis, FGF21 levels were significantly positive associated with lumbar BMD in postmenopausal women (L1-4, p = 0.007), independent of other factors, especially in fragility fracture group (L1-4, p = 0.001). In addition, a significant positive association was also observed between serum FGF21 levels and age in postmenopausal women (p0.05). We reveal a positive correlation between serum FGF21 concentrations with lumbar BMD in Chinese Han postmenopausal women. No significant correlations are present between serum FGF21 and bone turnover marks or serum FGF21 and fragility fracture in our study.

The aim of the study was to explore the association between the vitamin D pathway gene variations and the bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women.A total of 110 healthy postmenopausal Chinese women (61.51 ± 6.93 years) were enrolled. The participants were supplemented with calcium (600 mg/d) and calcitriol (0.25 μg/d), for 1 year. Four biomarkers, serum levels of beta C-terminal cross-linked telopeptides of type I collagen (β-CTX), amino-terminal propeptide of type I collagen (P1NP), parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] were measured at baseline and 12-month follow-up. Multivariate regression models were established to explore the statistical association between the change rate of the four biomarkers and 15 key genes within the vitamin D metabolic pathway.This exclusion process left 98 participants for analysis. Serum levels of P1NP, β-CTX and PTH were significantly decreased at the 12-month follow-up (all p 0.05). Serum 25(OH)D level had no significant change (p 0.05). No association was found between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation.Genetic background of postmenopausal Chinese women might not influence supplemental response of the biomarkers to calcium and low dose calcitriol.

The aim of the present study was to characterize the clinical manifestations and identify the mutations of Serpin family F member 1 (SERPINF1) and FK506 binding protein 10 (FKBP10) genes in Chinese patients with osteogenesis imperfecta (OI). Using whole‑exome sequencing in the first and third probands, a novel mutation was identified in SERPINF1 and a novel compound heterozygous mutation was revealed in FKBP10. Using Sanger sequencing, an additional novel mutation in SERPINF1 was identified in a proband of family 2. In family 1, the proband presented with a novel homozygous missense mutation of the SERPINF1 gene, c.1067T>A (V356E). In family 2, the proband had a novel homozygous deletion mutation of the SERPINF1 gene, c.283+473_643+104del (p.Ala96_Gly215del). Serum pigment‑epithelium‑derived factor concentration was not detected in probands with OI type VI. For both families, the proband's father was demonstrated to have a heterozygous mutation of SERPINF1, whereas no mutations was detected in the probands' mothers. An assessment of allelic copy numbers revealed a deletion of SERPINF1 in the mother of family 1. The results of the present study demonstrate that patients may have mild symptoms of OI with a large fragment deletion in the SERPINF1 gene. Thus, the phenotype of Chinese patients with type VI OI is milder than that of Caucasian and Korean patients. In family 3, the proband displayed a novel compound heterozygous mutation in FKBP10, c.813_814delGA (p.Glu271AspfsX101) and c.831delC (p.Gly278AlafsX20), and did not have Bruck syndrome. Codon 831 of the FKBP10 gene may represent a mutation hotspot for human OI. These results extend both the phenotypic and the genotypic contents of OI patients with SERPINF1 or FKBP10 mutations.

To investigate the effects of calcium and vitamin D supplementation on bone turnover marker levels, muscle strength and quality of life in postmenopausal Chinese women. A total of 485 healthy postmenopausal Chinese women (63.44±5.04 years) were enrolled in this open-label, 2-year, prospective, community-based trial. The participants were divided into group A, B, C, which were treated with calcium (600 mg/d) alone, calcium (600 mg/d) and cholecalciferol (800 IU/d) or calcium (600 mg/d) and calcitriol (0.25 μg/d), respectively, for 2 years. Serum levels of 25-hydroxyvitamin D, parathyroid hormone, β-CTX and P1NP were measured, and the muscle strength and quality of life were assessed at baseline and at 12- and 24-month follow-ups. Four hundred and sixty one participants completed this study. Serum levels of 25-hydroxyvitamin D were significantly increased in group C, but not changed in groups A and B at 24-month follow-up. Serum levels of parathyroid hormone, bone turnover marker β-CTX and bone formation marker P1NP were significantly decreased in group C, while serum levels of β-CTX were increased in group A at 24-month follow-up. The participants in group C maintained the grip strength, while those in groups A and B exhibited decreased grip strength at 24-month follow-up. The quality of life for the participants in groups B and C remained consistent, but that in group A was deteriorated at 24-month follow-up. Supplementation with calcitriol and calcium modifies the bone turnover marker levels, and maintains muscle strength and quality of life in postmenopausal Chinese women, whereas supplementation with cholecalciferol and calcium prevents aging-mediated deterioration in quality of life.

Hypophosphatemic rickets/osteomalacia is characterized by defective renal phosphate reabsorption and abnormal bone mineralization. Hypophosphatemic rickets/osteomalacia consists of inherited and acquired forms, many of which have unknown aetiology. In the present study, next‑generation sequencing‑based resequencing was used on samples from Chinese subjects with hypophosphatemic rickets/osteomalacia, aiming to detect the spectrum of pathogenic genes in these patients. A total of 86 hypophosphatemic rickets/osteomalacia patients (ranging from 3 to 70 years old) were recruited. Patients with tumour‑induced osteomalacia (TIO), renal tubular acidosis, renal osteodystrophy, and adefovir‑induced Fanconi syndrome were excluded. Targeted massively parallel resequencing of 196 candidate genes for hypophosphatemic rickets/osteomalacia was performed in the 86 affected unrelated individuals (cases) and in 100 unrelated healthy controls to identify new genes and mutations in known genes that cause hypophosphatemic rickets/osteomalacia. The results identified seven phosphate‑regulating gene with homologies to endopeptidases on the X chromosome (PHEX) mutations (of which two were novel) and one novel dentin matrix protein 1 (DMP1) mutation in eight patients. Following targeted exome sequencing data analysis, 14 candidate disease‑related gene loci were selected, two of which were of most concern regarding disease severity. Further validation of the present results is warranted, with additional sequencing projects and functional tests. To our knowledge, the present study is the largest cohort of cases with hypophosphatemic rickets/osteomalacia to undergo targeted resequencing. The diagnosis and understanding of the molecular aetiologies of these disorders will be improved by this fast and efficient approach.

Alendronate is an antiosteoporotic drug that targets the mevalonate pathway. To investigate whether the genetic variations in this pathway affect the clinical efficacy of alendronate in postmenopausal Chinese women with osteopenia or osteoporosis, 23 single-nucleotide polymorphisms (SNPs) in 7 genes were genotyped in 500 patients treated with alendronate for 12 months. Bone mineral density (BMD) was measured at baseline and after 12 months. The rs10161126 SNP in the 3' flanking region of MVK and the GTCCA haplotype in FDFT1 were significantly associated with therapeutic response. A 6.6% increase in BMD in the lumbar spine was observed in the GG homozygotes of rs10161126; AG heterozygotes and AA homozygotes experienced a 4.4 and 4.5% increase, respectively. The odds ratio (95% confidence interval) of G allele carriers to be responders in lumbar spine BMD was 2.06 (1.08-6.41). GTCCA haplotype in FDFT1 was more frequently detected in the group of responders than in the group of non-responders at the total hip (2.6 vs 0.5%, P=0.009). Therefore, MVK and FDFT1 polymorphisms are genetic determinants for BMD response to alendronate therapy in postmenopausal Chinese women.

The bone mineral density (BMD) of a total of 1,379 healthy postmenopausal Chinese women was measured. Ten tagging SNPs of the sclerostin (SOST) gene were genotyped. Our results suggest that the polymorphisms of the rs2023794 and rs74252774 in the SOST gene were associated with BMD of the lumbar spine in postmenopausal Chinese women.The purpose of the study was to determine the associations between polymorphisms of SOST gene and BMD in postmenopausal Chinese women.A total of 1,379 independent healthy postmenopausal Chinese women including 703 in our previous study were recruited. The BMD of the lumbar spine 1-4 (L1-4) and left proximal femur including total hip and femoral neck were measured by dual-energy X-ray absorptiometry. Ten tagging SNPs (rs1234612, rs1513670, rs1634330, rs1708635, rs2023794, rs7220711, rs74252774, rs851057, rs851058, and rs865429) of the SOST gene were genotyped.The rs2023794 and rs74252774 and the haplotype ACCATTCT of SOST gene were associated with age and body mass index (BMI) adjusted L1-4 BMD (P values were 0.010, 0.007, and 0.007, respectively) even after performing the Bonferroni multiple-significance-test correction. There was a clear trend in these regions that the CC genotype of the rs2023794 and the TT genotype of the rs74252774 have higher BMD values than other genotypes. The contributions of the rs2023794 and rs74252774 to the phenotypic variation of L1-4 BMD were 0.6 and 0.7 %, respectively. We failed to find any association between the 10 SNPs and 6 haplotypes of the SOST gene and BMD at the hip site in this study.Our results suggest that the polymorphisms of the rs2023794 and rs74252774 in the SOST gene were associated with BMD of the lumbar spine in a large sample of postmenopausal Chinese women.

The aims of this study were as follows: 1) to evaluate the association of serum sclerostin with bone mineral density (BMD) and markers of bone metabolism in postmenopausal Chinese women and 2) to observe the relationships of single-nucleotide polymorphisms (SNPs) within the sclerostin (SOST) gene with serum sclerostin, BMD, and markers of bone metabolism.A cross-sectional study was conducted with 703 postmenopausal Chinese women. Ten tagging SNPs (rs1234612, rs1513670, rs1634330, rs1708635, rs2023794, rs7220711, rs74252774, rs851057, rs851058, and rs865429) of the SOST gene were genotyped. Serum sclerostin and markers of bone metabolism were measured, including serum intact PTH, 25-hydroxyvitamin D [25(OH)D], procollagen type 1 N-terminal propeptide, and β-CrossLaps of type I collagen containing cross-linked C-telopeptide (β-CTX). The BMD of the lumbar spine and proximal femur were measured by dual-energy X-ray absorptiometry.Serum sclerostin was positively correlated with BMD at the lumbar spine, femoral neck, and total hip and with serum 25(OH)D (all P.01) but negatively correlated with β-CTX (P.01). The significant relationships between serum sclerostin and BMD and with serum β-CTX persisted, even after adjustments for age, body mass index, and serum 25(OH)D (all P.01). However, there was no correlation between serum sclerostin and age or serum procollagen type 1 N-terminal propeptide. We failed to identify a significant association between the SNP, haplotypes of SOST and BMD, or serum sclerostin.Our results suggested that serum sclerostin was positively correlated with the BMD at the lumbar spine, femoral neck, and total hip and with serum 25(OH)D but was negatively correlated with serum β-CTX. Genetic polymorphisms of SOST may not be a major contributor to variations in the serum sclerostin or BMD in postmenopausal Chinese women.

Dent disease comprises a group of X-linked recessive inherited renal tubular disorders, the symptoms of which include low-molecular-weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis, and progressive renal failure. We sought to characterize the clinical manifestations and to identify the mutations associated with this disease in Chinese patients. In total, 155 DNA samples were collected from one affected individual, four of his family members, and 150 healthy donors. All 12 exons and the exon-intron boundaries of the CLCN5 gene were amplified and directly sequenced in this Chinese family. The proband demonstrated osteomalacia, which had resulted in more than 10 fractures, LMWP, and renal failure. A single base 'G' deletion at nucleotide 246 (c. 246delG) was identified in exon 5 of the CLCN5 gene in this patient, resulting in a frame shift mutation (fsX) that changed the Threonine (Thr) residue in position 83 to Proline (Pro). The proband's mother was found to be a carrier of this mutation. The present study suggests that a novel frameshift mutation (c. 246delG) in exon 5 of the CLCN5 gene is responsible for Dent disease in this case. Our findings also expand the known spectrum of CLCN5 mutations.

PRD1-BF-1-RIZ1 homologous domain containing protein-16 (PRDM16) is a cell-autonomous transcriptional component that stimulates the development of brown fat cells. The aim of this study was to investigate the contribution of genetic variants of PRDM16 to obesity-related phenotype variations in Chinese.A total of 3204 subjects (consisting of 400 male-offspring nuclear families, 401 female-offspring nuclear families, and 729 unrelated older males) were recruited. Ten tag single nucleotide polymorphisms (SNPs) within the PRDM16 gene were genotyped using multiplex quantitative real-time PCR by Taqman assay. Body compositions were measured by dual-energy X-ray absorptiometry (DXA). The associations of the SNPs with the obesity-related phenotypes were analyzed using the quantitative transmission disequilibrium test (QTDT), GLM-ANOVA and PLINK statistical methods.Rs2236518 was the only SNP that was associated with BMI in young (aged 20-40 years) males (P=0.011) using QTDT, and in the older men (aged 50-80 years) (P=0.003) using GLM-ANOVA. No significant associations were detected in the females. Nor was a relationship found between any haplotype and obesity-related phenotypes. When PLINK was used, no significant relationship was detected between 10 SNPs and obesity-related phenotypes in any of the studied cohorts.Rs2236518 is associated with BMI in the young males (using QTDT), and the older males (using GLM-ANOVA).However, the result is not confirmed using PLINK. The discrepancy needs to be further addressed.

Introduction Inclusion-body myopathy (IBM) with Paget's disease of bone (PDB) and frontotemporal dementia (FTD), designated as IBMPFD, is a rare, autosomal dominant disorder (MIM 605382 ). IBMPFD is caused by mutations in the gene that encode valosin-containing protein (VCP). We investigated a Chinese family in which multiple members were diagnosed with PDB and suffered from weakness of the limbs. However, no members of this family were diagnosed with FTD. We made a preliminary diagnosis of PDB, but failed to identify an SQSTM1 mutation in any of the patients. We used whole-exome sequencing to identify the pathogenic gene mutation affecting the Chinese male proband. Materials and methods Altogether, 254 subjects, including one 56-year-old male proband, four affected, related individuals and additional nine family members from a non-consanguineous Chinese family, and 240 healthy donors were recruited and genomic DNA was extracted. All eight exons and the exon–intron boundaries of the SQSTM1 gene were amplified by polymerase chain reaction (PCR) and directly sequenced in five patients (II13, II4, II5, II8, II9). Using whole-exome sequencing, we identified a novel mutation in VCP as the disease-causing mutation. We confirmed the result by sequencing a 500-bp region of the promoter and the coding region of VCP in all 254 of the participants using Sanger sequencing. Results No mutation in the SQSTM1 gene was identified in the five patients examined using direct Sanger sequencing. However, through whole-exome sequencing we were able to identify a novel missense mutation in exon 3 of the VCP gene (p.Gly97Glu) in the Chinese male proband. This mutation was confirmed using Sanger sequencing. The proband, four affected individuals and three unaffected individuals carried this mutation. We were able to correctly diagnose the patients with atypical IBMPFD. Structural analysis of the p.Gly97Glu mutation in the VCP protein showed that the affected amino‐acid is located in the interface of the protein. This abnormality may therefore interfere with protein function. Conclusions This is the first report of a family from China with IBMPFD. A novel VCP mutation was found as the cause of atypical IBMPFD in a Chinese family. Our findings confirm that VCP gene mutations can be a pathogenic cause of IBMPFD.

By using whole-exome sequencing, we identified a homozygous guanine-to-adenine transition at the invariant -1 position of the acceptor site of intron 1 (c.97-1GA) in solute carrier organic anion transporter family member 2A1 (SLCO2A1), which encodes a prostaglandin transporter protein, as the causative mutation in a single individual with primary hypertrophic osteoarthropathy (PHO) from a consanguineous family. In two other affected individuals with PHO from two unrelated nonconsanguineous families, we identified two different compound heterozygous mutations by using Sanger sequencing. These findings confirm that SLCO2A1 mutations inactivate prostaglandin E(2) (PGE(2)) transport, and they indicate that mutations in SLCO2A1 are the pathogenic cause of PHO. Moreover, this study might also help to explain the cause of secondary hypertrophic osteoarthropathy.

Background and Aims Hypophosphatasia is a genetic disorder characterized by defective bone and tooth mineralization and a deficiency of serum and bone alkaline phosphatase activity. To date, few studies have identified gene mutations in Chinese patients with hypophosphatasia. We sought to characterize the clinical manifestations and identify the mutations associated with the disease in Chinese hypophosphatasia patients. Methods All 12 exons and the exon-intron boundaries of the ALPL gene were amplified and directly sequenced in two probands from unrelated Chinese families. The mutation sites were identified in other unaffected members of these two families and 100 healthy controls. Results In family 1, the proband displayed one novel splice site mutation, c.298-1G>A, which consisted of a homozygous G>A transition at nucleotide 298-1 in intron 4. The proband's mother displayed the heterozygous G/A ALPL gene mutation, but her father was identified as G/G homozygous. A paternity test ruled out false paternity and therefore confirmed that this splicing mutation occurred de novo either in the paternal germline or in the early development of the patient. In family 2, the proband revealed a novel missense mutation (c.1271T>C) in exon 11, which resulted in p.Val424Ala in the mature ALPL polypeptide. Furthermore, c.298-1G>A and c.1271T>C mutations were not found in unaffected family members of these two Chinese families and 100 unrelated controls. Conclusions Our study shows that the novel de novo splicing mutation c.298-1G>A in intron 4 and the missense mutation c.1271T>C in exon 11 of the ALPL gene are responsible for hypophosphatasia in some Chinese patients.

Association between ten single-nucleotide polymorphisms (SNPs) in the human ALOX12 and ALOX15 genes and variations in peak bone mineral density (BMD) in a large sample of Chinese nuclear families with female offspring using the quantitative transmission disequilibrium test (QTDT). Our results suggest that the genetic polymorphisms in both human ALOX12 and ALOX15 may contribute to variations in the peak BMD of Chinese women. The aim of this study was to investigate whether polymorphisms in the human ALOX12 and ALOX15 genes are associated with variations in peak BMD in Chinese nuclear families with female offspring. Each five SNPs in the ALOX12 and ALOX15 genes were genotyped in a total of 1,260 individuals from 401 Chinese nuclear families. The BMD of the lumbar spine, femoral neck and total hip was measured by dual-energy X-ray absorptiometry. We tested whether a single SNP or a haplotype was associated with peak BMD variations using the QTDT. Using QTDT to measure within-family associations in ALOX15, we observed a significant association between rs916055 and BMD in the lumbar spine (p = 0.027 in the permutation 1,000 test). However, in ALOX12, rs312470 was significantly associated with BMD in the femoral neck (p = 0.029 and p = 0.036 in the permutation 1,000 test). The results of a haplotype analysis supported the findings of the single locus test for ALOX15. Our results suggest that the genetic polymorphisms in both human ALOX12 and ALOX15 may contribute to variations in the peak BMD of Chinese women.

Osteopetrosis is a heritable bone disorder resulting from a deficiency of or a functional defect in osteoclasts. We aimed to characterize the molecular defects and clinical manifestations in Chinese patients with osteopetrosis by studying 12 unrelated osteopetrosis families. The entire coding region and adjacent splice sites of the CLCN7, TCIRG1, LRP5 and SOST genes were amplified and directly sequenced. X-rays of hip and lumbar spine, bone mineral density and bone turnover markers were examined simultaneously. Family history and fracture history were collected using a questionnaire. Among 12 unrelated families, 10 families were diagnosed with autosomal dominant osteopetrosis type II (ADOII) with 10 probands and 3 affected subjects. Two individuals in the other two families were diagnosed with uncategorized osteopetrosis because no mutations were detected in any of the four studied genes. Eight mutations, including two reported mutations (R767W and E798FS) and six novel mutations (E313K, A316G, R743W, G741R, W127G and S290F), were detected in the CLCN7 gene from 12 living ADOII patients. Among them, R767W and R743W mutations were two common mutations that were each found in 20% of 10 ADOII probands. In CLCN7-related ADOII patients, long bone fractures and elevated serum CK level were two major clinical phenotypes, especially in patients younger than 18 years. Further functional studies of the above eight mutations in the CLCN7 gene are needed in the future.

Objective: Arachidonate 12-lipoxygenase (ALOX12) is a member of the lipoxygenase superfamily, which catalyzes the incorporation of molecular oxygen into polyunsaturated fatty acids. The products of ALOX12 reactions serve as endogenous ligands for peroxisome proliferator-activated receptor γ (PPARG). The activation of the PPARG pathway in marrow-derived mesenchymal progenitors stimulates adipogenesis and inhibits osteoblastogenesis. Our objective was to determine whether polymorphisms in the ALOX12 gene were associated with variations in peak bone mineral density (BMD) and obesity phenotypes in young Chinese men. Methods: All six tagging single-nucleotide polymorphisms (SNPs) in the ALOX12 gene were genotyped in a total of 1215 subjects from 400 Chinese nuclear families by allele-specific polymerase chain reaction. The BMD at the lumbar spine and hip, total fat mass (TFM) and total lean mass (TLM) were measured using dual-energy X-ray absorptiometry. The pairwise linkage disequilibrium among SNPs was measured, and the haplotype blocks were inferred. Both the individual SNP markers and the haplotypes were tested for an association with the peak BMD, body mass index, TFM, TLM and percentage fat mass (PFM) using the quantitative transmission disequilibrium test (QTDT). Results: Using the QTDT, significant within-family association was found between the rs2073438 polymorphism in the ALOX12 gene and the TFM and PFM (P=0.007 and 0.012, respectively). Haplotype analyses were combined with our individual SNP results and remained significant even after correction for multiple testing. However, we failed to find significant within-family associations between ALOX12 SNPs and the BMD at any bone site in young Chinese men. Conclusions: Our present results suggest that the rs2073438 polymorphism of ALOX12 contributes to the variation of obesity phenotypes in young Chinese men, although we failed to replicate the association with the peak BMD variation in this sample. Further independent studies are needed to confirm our findings.

To determine the associations between HOXD4 gene polymorphisms with peak bone mineral density (BMD) throughing measuring three tagging single nucleotide polymorphisms (tagSNPs), including rs1867863, rs13418078, and rs4972504, in HOXD4. Four hundred Chinese nuclear families with male offspring (1215 subjects) and 401 Chinese nuclear families with female offspring (1260 subjects) were recruited. BMD of the lumbar spine 1-4 (L1-4) and left proximal femur including total hip and femoral neck were measured by dual-energy X-ray absorptiometry. The quantitative transmission disequilibrium test (QTDT) was performed to investigate the association among the tagging SNPs, haplotypes and peak BMD. Only the CC genotype was identified in rs13418078 in the Chinese population, unlike other populations. We failed to find significant within-family association among these SNPs, haplotypes and peak BMD at any bone site in either male- or female-offspring nuclear families. The results suggest that genetic polymorphisms in HOXD4 may not be a major contributor to the observed variability in peak BMD in the lumbar spine and the hip in Chinese men and women.

Osteoclastic activity is mainly assessed by measurement of urinary markers (eg C-terminal cross-linked telopeptides of type I collagen, N-terminal cross-linked telopeptides of type I collagen etc), the levels of which could often be affected by renal clearance. Recently, serum tartrate-resistant acid phosphatase 5b (TRACP5b) has been used as an alternative serum marker to evaluate osteoclastic activity. We investigated the age-related changes of TRACP5b level and its association with bone mineral density (BMD) in Chinese women. Seven-hundred and twenty-two Chinese mainland women aged 20–79 years were recruited in the study. Serum TRACP5b level was measured using immunoassay to evaluate the state of bone resorption. Bone mineral density (BMD) (g/cm2) at lumbar spine 1–4 and proximal femur were measured by duel-energy X-ray absorptiometry. The serum TRACP5b level reached a bottom value in premenopausal women aged 30–39, gradually increased in women aged 40–49, rapidly rose in women aged 50–59, and culminated with a maximum value in women aged 60–69 before a slow drop in women aged 70–79. The average level of TRACP5b was significantly higher in postmenopausal women [(3.29±1.07) U/L] than in premenopausal women ([1.70±0.59] U/L). The levels of TRACP5b were inversely correlated with BMD at all measured sites (P

Osteogenesis imperfecta (OI) is an inherited connective tissue disorder characterized by brittle bone fractures. The aim of the present study was to investigate the pathogenic gene mutation spectrum and clinical manifestations of mutations in collagen type I, alpha 1 (COL1A1) and collagen type I, alpha 2 (COL1A2) genes in Chinese patients with OI. A total of 61 unrelated Chinese OI patients with COL1A1 and COL1A2 mutations were recruited. All the exons and the exon-intron boundaries of the COL1A1 and COL1A2 genes were amplified and directly sequenced and lumbar spine bone mineral density was measured by dual‑energy X‑ray absorptiometry. The mutations of the 61 probands included 33 missense mutations, 8 nonsense mutations, 7 splicing variants and 13 frameshift mutations in COL1A1 and COL1A2 genes. A total of 25 novel mutations were identified, including 18 in COL1A1 and 7 in COL1A2. The mutations p.Gly257Arg, p.Gly767Ser and p.Gly821Ser in COL1A1 and p.Gly337Ser in COL1A2 may be located at a mutation hotspot for human OI due to the high repetition rate in OI patients. Family history was positive for OI in 33 probands (54%). All probands had suffered fractures and the most common fracture site was the femur. A total of 49 probands presented with blue sclerae (80.3%), 20 probands suffered from dentinogenesis imperfecta (32.8%) and 1 patient had hearing loss (1.6%). These findings may improve understanding of the pathogenic gene mutation spectrum and the clinical manifestations of mutations of COL1A1 and COL1A2 genes in Chinese patients with OI.

Inactivating mutations in phosphate-regulating gene with homologies to endopeptidase on the X chromosome (PHEX) have been identified as a cause of X-linked hypophosphatemic rickets (XLH; OMIM 307800). In the present study, we enrolled 43 patients from 18 unrelated families clinically diagnosed with hypophosphatemic rickets and 250 healthy controls. For each available individual, all 22 exons with their exon-intron boundaries of the PHEX gene were directly sequenced. The levels of serum fibroblast growth factor 23 (FGF23) were measured as well. Sequencing analysis detected 17 different PHEX gene mutations, and 7 of these were identified as novel: 3 missense mutations, including c.304G>A (p.Gly102Arg) in exon 3, c.229T>C (p.Cys77Arg) in exon 3 and c.824T>C (p.Leu275Pro) in exon 7; 2 deletion mutations, including c.528delT (p.Glu177LysfsX44) in exon 5 and c.1234delA (p.Ser412ValfsX12) in exon 11; and 2 alternative splicing mutations, including c.436_436+1delAG in intron 4 at splicing donor sites and c.1483-1G>C in intron 13 at splicing acceptor sites. Moreover, 6 mutations were proven to be de novo in 6 sporadic cases and the probands were all females. No mutations were found in the 250 healthy controls. The serum levels of FGF23 varied widely among the patients with XLH, and no significant difference was found when compared with those of the healthy controls. On the whole, the findings of this study provide new insight into the spectrum of PHEX mutations and provide potential evidence of a critical domain in PHEX protein. In addition, the finding of an overlap of the serum FGF23 levels between the patients with XLH and the healthy controls indicates its limited diagnostic value in XLH.

Oral risedronate is effective in the treatment of postmenopausal osteoporosis when administered daily, weekly, or monthly. In this 1-year, randomized, double-blind, multicenter study we compared the weekly 35-mg and daily 5-mg risedronate dosing regimens in the treatment of Chinese postmenopausal women with osteoporosis or osteopenia.Postmenopausal women with primary osteoporosis or osteopenia were randomly assigned to the weekly group or daily group (n=145 for each) that received oral risedronate 35 mg once a week or 5 mg daily, respectively, for 1 year. The subjects' bone mineral densities (BMDs), bone turnover markers (P1NP and β-CTX), new vertebral fractures, and adverse events were assessed at baseline and during the treatments.All subjects in the weekly group and 144 subjects in the daily group completed the study. The primary efficacy endpoint after 1 year, ie the mean percent changes in the lumbar spine BMD (95% CI) were 4.87% (3.92% to 5.81%) for the weekly group and 4.35% (3.31% to 5.39%) for the daily group. The incidences of clinical adverse events were 48.3% in the weekly group and 54.2% in the daily group.The weekly 35-mg and daily 5-mg risedronate dosing regimens during 1 year of follow-up show similar efficacy in improving BMDs and biochemical markers of bone turnover in Chinese postmenopausal women with osteoporosis or osteopenia. Moreover, the two dosing regimens exhibit similar safety and tolerability.

OBJECTIVE: X-linked dominant hypophosphatemia (XLH) is the most prevalent form of inherited rickets/osteomalacia in humans. The aim of this study was to identify PHEX gene mutations and describe the clinical features observed in 6 unrelated Chinese families and 3 sporadic patients with hypophosphatemic rickets/osteomalacia. METHODS: For this study, 45 individuals from 9 unrelated families of Chinese Han ethnicity (including 16 patients and 29 normal phenotype subjects), and 250 healthy donors were recruited. All 22 exons and exon-intron boundaries of the PHEX gene were amplified by polymerase chain reaction (PCR) and directly sequenced. RESULTS: The PHEX mutations were detected in 6 familial and 3 sporadic hypophosphatemic rickets/osteomalacia. Altogether, 2 novel mutations were detected: 1 missense mutation c.1183G>C in exon 11, resulting in p.Gly395Arg and 1 missense mutation c.1751A>C in exon 17, resulting in p.His584Pro. No mutations were found in the 250 healthy controls. CONCLUSIONS: Our study increases knowledge of the PHEX gene mutation types and clinical phenotypes found in Chinese patients with XLH, which is important for understanding the genetic basis of XLH. The molecular diagnosis of a PHEX genetic mutation is of great importance for confirming the clinical diagnosis of XLH, conducting genetic counseling, and facilitating prenatal intervention, especially in the case of sporadic patients.

Dent disease comprises a group of X-linked recessive inherited renal tubular disorders, the symptoms of which include low-molecular-weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis, and progressive renal failure. We sought to characterize the clinical manifestations and to identify the mutations associated with this disease in Chinese patients. In total, 155 DNA samples were collected from one affected individual, four of his family members, and 150 healthy donors. All 12 exons and the exon-intron boundaries of the CLCN5 gene were amplified and directly sequenced in this Chinese family. The proband demonstrated osteomalacia, which had resulted in more than 10 fractures, LMWP, and renal failure. A single base 'G' deletion at nucleotide 246 (c. 246delG) was identified in exon 5 of the CLCN5 gene in this patient, resulting in a frame shift mutation (fsX) that changed the Threonine (Thr) residue in position 83 to Proline (Pro). The proband's mother was found to be a carrier of this mutation. The present study suggests that a novel frameshift mutation (c. 246delG) in exon 5 of the CLCN5 gene is responsible for Dent disease in this case. Our findings also expand the known spectrum of CLCN5 mutations.

Objectives Mutations in the CYP27B1 gene, which encodes vitamin D 1α-hydroxylase, are the genetic basis of vitamin D-dependent rickets type 1A (VDDR1A, MIM 264700). The aim of this study was to investigate a novel CYP27B1 mutation and its clinical manifestations. Methods VDDR1A was diagnosed based on clinical presentation, a physical examination, bone characteristics on an X-ray, and laboratory results. A molecular model of the CYP27B1 protein was constructed using the SWISS-MODEL server and Swiss-PdbViewer. Results We sequenced the CYP27B1 gene in a 5-year-old male child who presented with growth retardation and a history of frequent hand, leg, and perioral twitching since the age of 12 months. We identified a compound heterozygous mutation consisting of two missense mutations: one in exon 7 (R389C [c.1165C>T]) and one in exon 8 (R459C [c.1375C>T]). We used the wild-type CYP27B1 as a receptor and calcidiol as a ligand to predict the interaction between the R459 site and calcidiol. According to the predicted structure, the wild-type R459 residue localizes to the pocket where CYP27B1 binds to its ligand. Conclusions According to the Human Gene Mutation Database, the compound heterozygous mutation identified in our patient is novel and has not yet been reported in the literature. This mutation provides a new basis for further research on VDDR1A and for the development of clinical diagnostics.

OBJECTIVE Osteosclerosis (OMIM: 144750) is a type of autosomal dominant bone disease caused by a mutation in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. The case of a Chinese family with two affected individuals is reported in the present study in order to investigate the clinical characteristics and virulence genes of this sclerosing bone disorder. METHODS Biochemical and radiographic examinations and bone mineral density (BMD) and genetic analyses were performed in two patients and eight other family members. RESULTS The 40-year-old proband (II-1) and her 64-year-old mother (I-2) both had chronic lumbodorsal pain, an elongated mandible and torus palatinus in the center of the hard palate. No fractures were observed in any of the family members. Skull, mandibular and pelvic X-rays in each of the two patients revealed thickened cranial plates, an enlarged sella turcica, an elongated mandible and cortical thickening of the long bones. The BMD values of the two patients was significantly higher than the standard age- and sex-matched adult mean reference values. Both patients had higher serum sclerostin levels, while their renal function markers and serum calcium, phosphonium, parathyroid hormone (PTH) and 25(OH)D levels were within the normal ranges. The heterozygous missense mutation p.Ala242Thr in exon 4 of the LRP5 gene was detected in the two patients, while the other family members and 200 healthy donors had normal wild-type genotypes. CONCLUSION The A242T mutation in the LRP5 gene resulted in a high bone mass phenotype with an elongated mandible and torus palatinus in this osteosclerotic family.

The reference ranges of bone turnover markers (BTMs) were important during the treatment of osteoporosis, and the associations with bone mineral density (BMD) were controversial. The aim of this study was to establish the reference ranges of N-terminal procollagen of type l collagen (P1NP), osteocalcin (OC), and beta C-terminal cross-linked telopeptides of type I collagen (β-CTX) in Shanghai area and to investigate the relationships between BTMs and BMD in postmenopausal women. 2,799 subjects recruited in Shanghai City were measured BTMs to establish the reference ranges. Additional 520 healthy postmenopausal women were also measured BTMs, these women measured BMD in addition. BTMs were measured using the Roche electrochemiluminescence system. We used the age range of 35 to 45-year-olds to calculate reference intervals. The reference range of OC was 4.91 to 13.90 ng/mL for women and 5.58 to 16.57 ng/mL for men, P1NP was 13.72 to 32.90 ng/mL for women and 16.89 to 42.43 ng/mL for men, andβ-CTX was 0.112 to 0.210 ng/mL for women and 0.100 to 0.378 ng/mL for men. BTMs significantly negatively correlated with lumbar spine and femoral and total hip in postmenopausal women ( = −0.157~−0.217,P< 0.001). We established the normal reference ranges of P1NP, OC, andβ-CTX in the Shanghai area. This study also found that BTMs correlated with BMD and suggested that BTMs were the key determining factors of early BMD decreases.

OBJECTIVE: Lipoxygenase (LOX) is one of the major metabolic enzymes for arachidonic acid, which has been reported to be associated with many postmenopausal and many hormone-related diseases. In rats, selective inhibition of the LOX pathway led to defective ovulation. However, little is known about the association of the LOX-related genes with menstruation in women. In this study, we investigated the possible association of two key gene (ALOX12 and ALOX15) polymorphisms with age of menarche and menopause in Chinese women. METHODS: Six tagging single nucleotide polymorphisms (SNPs) of ALOX12 and five SNPs of ALOX15 were genotyped. The association of single SNPs and haplotypes in two candidate genes and age at menarche (AAM) variation was tested in 401 Chinese nuclear families using the quantitative transmissing disequilibrium test. Furthermore, the association between these SNPs and haplotypes and age at natural menopause (AANM) in 710 postmenopausal Chinese women was measured. RESULTS: Using family- and population-based statistical procedures, significant association was found between SNPs rs312462 in ALOX12 and AAM in nuclear families (P = 0.043), and three SNPs (rs2292350, rs312470, and rs312462) in ALOX12 were significantly associated with AANM in postmenopausal women (P = 0.012, P = 0.045, and P = 0.033, respectively). Haplotype analyses corroborated our single SNP results (P = 0.030). However, we failed to find a significant association between ALOX15 gene polymorphisms and AAM as well as AANM (P > 0.05). CONCLUSIONS: Our present results suggest that genetic variations in ALOX12 are associated with both the onset and cessation of menstruation in Chinese women living in Shanghai.

Myostatin gene is a member of the transforming growth factor-β (TGF-β) family that negatively regulates skeletal muscle growth. Genetic polymorphisms in Myostatin were found to be associated with the peak bone mineral density (BMD) in Chinese women. The purpose of this study was to investigate whether Myostatin played a role in the normal variation in peak BMD, lean mass (LM), and fat mass (FM) of Chinese men. Four hundred male-offspring nuclear families of Chinese Han ethnic group were recruited. Anthropometric measurements, including the peak BMD, body LM and FM were measured using dual-energy X-ray absorptiometry (DXA). The single nucleotide polymorphisms (SNPs) studied were tag-SNPs selected by sequencing. Both rs2293284 and +2278GA were genotyped using TaqMan assay, and rs3791783 was genotyped with PCR-restriction fragment length polymorphism (RFLP) analysis. The associations of the SNPs with anthropometric variations were analyzed using the quantitative transmission disequilibrium test (QTDT). Using QTDT to detect within-family associations, neither single SNP nor haplotype was found to be associated with peak BMD at any bone site. However, rs3791783 was found to be significantly associated with fat mass of the trunk (P

To compare the effects of cholecalciferol (800 IU/d) and calcitriol (0.25 μg/d) on calcium metabolism and bone turnover in Chinese postmenopausal women with vitamin D insufficiency.One hundred Chinese postmenopausal women aged 63.8±7.0 years and with serum 25-hydroxyvitamin D [25(OH)D] concentration30 ng/mL were recruited. The subjects were divided into 2 groups based on the age and serum 25(OH)D concentration: 50 subjects (group A) received cholecalciferol (800 IU/d), and 50 subjects (group B) received calcitriol (0.25 μg/d) for 3 months. In addition, all the subjects received Caltrate D (calcium plus 125 IU cholecalciferol) daily in the form of one pill. The markers of calcium metabolism and bone turnover, including the serum levels of calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone, 25(OH)D and β-CrossLaps of type I collagen containing cross-linked C-telopeptide (β-CTX), were measured before and after the intervention.After the 3-month intervention, the serum 25(OH)D concentration in group A was significantly increased from 16.01 ± 5.0 to 20.02 ± 4.5 ng/mL, while that in group B had no significant change. The serum calcium levels in both the groups were significantly increased (group A: from 2.36 ± 0.1 to 2.45 ± 0.1 mmol/L; group B: from 2.36 ± 0.1 to 2.44 ± 0.1 mmol/L). The levels of serum intact parathyroid hormone in both the groups were significantly decreased (group A: from 48.56 ± 12.8 to 39.59 ± 12.6 pg/mL; group B: from 53.67 ± 20.0 to 40.32 ± 15.4 pg/mL). The serum levels of β-CTX in both the groups were also significantly decreased (group A: from 373.93 ± 135.3 to 325.04 ± 149.0 ng/L; group B: from 431.00 ± 137.1 to 371.74 ± 185.0 ng/L).We concluded that both cholecalciferol (800 IU/d) and calcitriol (0.25 μg/d) plus Caltrate D modifies the serum calcium and bone turnover markers in Chinese postmenopausal women with vitamin D insufficiency. In addition, cholecalciferol (800 IU/d) significantly increased the serum 25(OH)D concentration.

To identify the susceptibility genes for osteoporotic fracture in postmenopausal Chinese women, a two-stage case-control association study using joint analysis was conducted in 1046 patients with nontraumatic vertebra, hip, or distal radius fractures and 2303 healthy controls. First, 113 single-nucleotide polymorphisms (SNPs) in 16 potential osteoporosis candidate genes reported in recent genomewide association studies, meta-analyses studies, large-scale association studies, and functional studies were genotyped in a small-sample-size subgroup consisting of 541 patients with osteoporotic fractures and 554 healthy controls. Variants and haplotypes in SPTBN1, TNFRSF11B, CNR2, LRP4, and ESR1 that have been identified as being associated with osteoporotic fractures were further reanalyzed in the entire case-control group. We identified one SNP in TNFRSF11B (rs3102734), three SNPs in ESR1 (rs9397448, rs2234693, and rs1643821), two SNPs in LRP4 (rs17790156 and rs898604), and four SNPs in SPTBN1 (rs2971886, rs2941583, rs2941584, and rs12475342) were associated with all of the broadly defined osteoporotic fractures. The most significant polymorphism was rs3102734, with increased risk of osteoporotic fractures (odds ratio, 1.35; 95% confidence interval [CI], 1.17–1.55, Bonferroni p = 2.6 × 10−4). Furthermore, rs3102734, rs2941584, rs12475342, rs9397448, rs2234693, and rs898604 exhibited significant allelic, genotypic, and/or haplotypic associations with vertebral fractures. SNPs rs12475342, rs9397448, and rs2234693 showed significant genotypic associations with hip fractures, whereas rs3102734, rs2073617, rs1643821, rs12475342, and rs2971886 exhibited significant genotypic and/or haplotypic associations with distal radius fractures. Accordingly, we suggest that in addition to the clinical risk factors, the variants in TNFRSF11B, SPTBN1, ESR1, and LRP4 are susceptibility genetic loci for osteoporotic fracture in postmenopausal Chinese women. © 2012 American Society for Bone and Mineral Research © 2012 American Society for Bone and Mineral Research

Genetic variation in ALOX12, which encoded human 12-lipoxygenase, was found to be associated with fat mass in young Chinese men. The objective of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) and haplotypes in the ALOX15 gene and obesity-related phenotypes in Chinese nuclear families with male offspring. We recruited 1,296 subjects from 427 nuclear families with male offspring and genotyped five SNPs (rs9894225, rs748694, rs2619112, rs2619118, and rs916055) in the ALOX15 gene locus. The total fat mass (TFM), trunk fat mass (tFM), leg fat mass (LFM) and arm fat mass (AFM) were measured using dual-energy X-ray absorptiometry (DXA). The percentage of fat mass (PFM) was the ratio of TFM and body weight. The association between SNPs and haplotypes of ALOX15 and obesity-related phenotypic variation was measured using quantitative transmission disequilibrium test (QTDT). Using QTDT to measure family-based genetic association, we found that rs916055 had a statistically significant association with PFM (P=0.038), whereas rs916055 had a marginal but statistically insignificant association with tFM (P=0.093). The multiple-parameter 1000 permutations test agreed with the family-based association results: both showed that rs916055 had a statistically significant association with PFM (P=0.033). rs916055 in ALOX15 gene was significantly associated with the percentage of fat mass in Chinese nuclear families with male offspring in the family-based association study using QTDT approach.

Previous studies have suggested that changes in hip geometry increase the risk of hip fracture. The aim of this study was to identify whether body composition were associated with hip geometry or bone mineral density (BMD) in a large sample of Chinese people. A total of 2072 subjects aged 20-79 yr (including 700 males and 1372 females) were selected. The following measurements were taken: lumbar spine (L1-4); proximal femur BMD; lean mass (LM); fat mass (FM); and hip geometric parameters, including hip axis length (HAL), cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), neck-shaft angle, and femur strength index (SI) by dual-energy X-ray absorptiometry. FM and LM were positively correlated with HAL, CSMI, and CSA, and negatively correlated with SI in both men and women. Multiple regression analysis showed that leg LM contributions to HAL, CSMI, and CSA variance were 12.6-37.6%. Compared with FM, LM was generally more strongly related to hip geometry and BMD in young and old men and women. Body composition was a good predictor for hip geometry parameter variation and BMD variation.

Low density lipoprotein receptor-related protein 2 gene (LRP2) is located next to the genomic region showing suggestive linkage with both hip and wrist bone mineral density (BMD) phenotypes. LRP2 knockout mice showed severe vitamin D deficiency and bone disease, indicating the involvement of LRP2 in the preservation of vitamin D metabolites and delivery of the precursor to the kidney for the generation of 1α,25(OH)(2)D(3). In order to investigate the contribution of LRP2 gene polymorphisms to the variation of BMD in Chinese population, a total of 330 Chinese female-offspring nuclear families with 1088 individuals and 400 Chinese male-offspring nuclear families with 1215 individuals were genotyped at six tagSNPs of the LRP2 gene (rs2389557, rs2544381, rs7600336, rs10210408, rs2075252 and rs4667591). BMD values at the lumbar spine 1-4 (L1-4) and hip sites were measured by DXA. The association between LRP2 polymorphisms and BMD phenotypes was assessed by quantitative transmission disequilibrium tests (QTDTs) in female- and male-offspring nuclear families separately. In the female-offspring nuclear families, rs2075252 and haplotype GA of rs4667591 and rs2075252 were identified in the nominally significant total association with peak BMD at L1-4; however, no significant within-family association was found between peak BMD at the L1-4 and hip sites and six tagSNPs or haplotypes. In male-offspring nuclear families, neither the six tagSNPs nor the haplotypes was in total association or within-family association with the peak BMD variation at the L1-4 and hip sites by QTDT analysis. Our findings suggested that the polymorphisms of LRP2 gene is not a major factor that contributes to the peak BMD variation in Chinese population.

To study whether genetic polymorphisms of COL1A1 and COL1A2 genes affected the onset of fracture in postmenopausal Chinese women. SNPs in COL1A1 and COL1A2 genes were identified via direct sequencing in 32 unrelated postmenopausal Chinese women. Ten SNPs were genotyped in 1252 postmenopausal Chinese women. The associations were examined using both single-SNP and haplotype tests using logistic regression. Twenty four (4 novel) and 28 (7 novel) SNPs were identified in COL1A1 and COL1A2 gene, respectively. The distribution frequencies of 2 SNPs in COL1A1 (rs2075554 and rs2586494) and 3 SNPs in COL1A2 (rs42517, rs1801182, and rs42524) were significantly different from those documented for the European Caucasian population. No significant difference was observed between fracture and control groups with respect to allele frequency or genotype distribution in 9 selected SNPs and haplotype. No significant association was found between fragility fracture and each SNP or haplotype. The results remained the same after additional corrections for other risk factors such as weight, height, and bone mineral density. Our results show no association between common genetic variations of COL1A1 and COL1A2 genes and fracture, suggesting the complex genetic background of osteoporotic fractures.

Dominant inheritance of osteogenesis imperfecta (OI) is caused by mutations in COL1A1 or COL1A2, the genes that encode type I collagen, and CRTAP, LEPRE1, PPIB, FKBP10, SERPINH1, and SP7 mutations were recently detected in a minority of patients with autosomal recessive OI. However, these findings have been mostly restricted to Western populations. The proportion of mutations and the correlations between genotype and phenotype in Chinese patients with OI are completely unknown. In this study, mutation analyses were performed for COL1A1, COL1A2, CRTAP, and LEPRE1 in a cohort of 58 unrelated Chinese patients with OI; the relationship between collagen type I mutations and clinical features was examined. A total of 56 heterozygous mutations were identified in COL1A1 and COL1A2, including 43 mutations in COL1A1 and 13 mutations in COL1A2. Among the 56 causative COL1A1 and COL1A2 mutations, 24 novel mutations were found, and 25 (44.6%) resulted in the substitution of a glycine within the Gly-X-Y triplet domain of the triple helix. Compared with COL1A1 haploinsufficiency (n = 23), patients with mutations affecting glycine residues had a severe skeletal phenotype. In patients 18 years of age or older, on average patients with COL1A1 haploinsufficiency were taller and had higher femoral neck bone mineral density than with patients with helical mutations. Interestingly, we found two novel compound heterozygous mutations in the LEPRE1 gene in two unrelated families with autosomal recessive OI. Although the genotype–phenotype correlation is still unclear, our findings are useful to understand the genetic basis of Chinese patients with OI.

To investigate the effect of low-density lipoprotein receptor-related protein 5 (LRP5) gene polymorphisms on bone and obesity phenotypes in young Chinese men. A total of 1244 subjects from 411 Chinese nuclear families were genotyped by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique at the Q89R, N740N, and A1330V sites in the LRP5 gene. Bone mineral density (BMD) in the lumbar spine and the hip, total fat mass and total lean mass were measured using dual-energy X-ray absorptiometry. The association between LRP5 gene polymorphisms and peak BMD, body mass index (BMI), total fat mass, total lean mass and percentage of fat mass was assessed using a quantitative transmission disequilibrium test (QTDT). No significant within-family associations were found between genotypes or haplotypes of the LRP5 gene and peak BMD, BMI, total fat mass, total lean mass and percentage of fat mass. The 1000 permutations that were subsequently simulated were in agreement with these within-family association results. Our results suggest that common polymorphic variations of the LRP5 gene do not influence peak bone mass acquisition and obesity phenotypes in young Chinese men.

Background The Wnt/beta-catenin signaling pathway plays an important role in skeletal development. Polymorphisms of frizzled-related protein (FRZB), an antagonist of this pathway, may generate variations in bone mineral density (BMD). In this study, we analyzed the association between FRZB genotypes and peak BMD variation in the spines and hips of two relatively large samples of Chinese female-offspring and male-offspring nuclear families. Methods We recruited 1,260 subjects from 401 female-offspring nuclear families and 1,296 subjects from 427 male-offspring nuclear families and genotyped four tagging single nucleotide polymorphisms (tagSNPs) (rs6433993, rs409238, rs288324, and rs4666865) spanning the entire FRZB gene. The SNPs rs288326 and rs7775, which are associated with hip osteoarthritis, were not selected in this study because of their low minor allele frequencies (MAFs) in Chinese people. The quantitative transmission disequilibrium test (QTDT) was used to analyze the association between each SNP and haplotype with peak BMD in female- and male-offspring nuclear families. Results In the female-offspring nuclear families, we found no evidence of an association between either single SNPs or haplotypes and peak BMD in the spine or hip. In the male-offspring nuclear families, no within-family association was observed for either SNPs or haplotypes, although a significant total association was found between rs4666865 and spine BMD (P = 0.0299). Conclusion Our results suggest that natural variation in FRZB is not a major contributor to the observed variability in peak BMD in either Chinese females or males. Because ethnic differences in the FRZB genotypes may exist, other studies in different population are required to confirm such results.

The goal of this study was to determine whether polymorphisms in the vitamin D receptor (VDR) and estrogen receptor alpha (ESR1) genes are associated with variations of peak bone mineral density (BMD) and obesity phenotypes in young Chinese men.A total of 1215 subjects from 400 Chinese nuclear families were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele-specific multiple PCR (ASM-PCR) analysis at the ApaI, FokI, and CDX2 sites in the VDR gene and the PvuII and XbaI sites in the ESR1 gene. BMD at the lumbar spine and hip, total fat mass, and total lean mass were measured using dual energy X-ray absorptiometry. The associations between VDR and ESR1 gene polymorphisms with peak BMD, body mass index (BMI), total fat mass, total lean mass, and percentage fat mass (PFM) were determined using quantitative transmission disequilibrium tests (QTDTs).Using QTDTs, no significant within-family associations were obtained between genotypes or haplotypes of the VDR and ESR1 genes and peak BMD. For the obesity phenotypes, the within-family associations were significant between CDX2 genotypes and BMI (P=0.046), fat mass (P=0.004), and PFM (P=0.020). Further, PvuII was significantly associated with the variation of fat mass and PFM (P=0.002 and P=0.039, respectively). A subsequent 1000 permutations were in agreement with these within-family association results.Our findings showed that VDR and ESR1 polymorphisms were associated with total fat mass in young Chinese men, but we failed to find a significant association between VDR and ESR1 genotypes and peak BMD. These findings suggested that the VDR and ESR1 genes are quantitative trait loci (QTL) underlying fat mass variation in young Chinese men.

Here we report the identification of two different mutations in chloride channel 7 gene in two unrelated patients with autosomal dominant osteopetrosis type II. We determined that one patient (a 32-year-old woman) carried a heterozygous gene for a R767W mutation in exon 24, and another patient (a 17-year-old boy) carried a heterozygous gene for a novel frameshift mutation (Glu798FS) in exon 25. Recent studies have reported loss-of-function mutations in the chloride channel 7 (CLCN7) gene as a cause of autosomal dominant osteopetrosis type II (ADO-II). The identification of gene mutations in Chinese with ADO has not been reported previously. In this study, we identified mutations of the CLCN7 gene in two unrelated Chinese families with ADO-II. Two probands with ADO-II were diagnosed based on their bone characteristics on X-rays and their laboratory results. All 25 exons of the CLCN7 gene, including the exon-intron boundaries, were sequenced. We found in family 1 that the proband (a 32-year-old woman) was heterozygous for a CLCN7 mutation. The nonsynonymous mutation consisted of a heterozygous C/T transition at codon 2327 in exon 24, which resulted in an arginine (CGG)-to tryptophan (TGG) substitution at position 767 (R767W). The same heterozygous mutation (C/T) was determined in her father and son, who were asymptomatic with normal skeleton radiography. In family 2, we found that the proband (a 17-year-old boy) carried a novel frameshift mutation (Glu798FS) resulting from a G insertion between codon 60 and codon 61 in exon 25. The heterozygous -/G insertion is predicted to elongate the peptide of CLCN7 by 120 amino acids after position 797 amino acids. Similarly, some individuals of this family carried the same heterozygous mutation, but they are all asymptomatic. Furthermore, the R767W and Glu798FS mutations were not found in 100 unrelated controls. Our present findings suggest that the novel Glu798FS mutation in exon 25 and R767W in exon 24 in the CLCN7 gene were responsible for ADO-II in these Chinese patients.

Hip axis length (HAL) has been proposed as an independent predictor of hip fracture risk in Caucasian females. There are, however, few data concerning its predictive risk in Chinese. The aim of this study was to investigate the changes of HAL in healthy Chinese population and the relationship between HAL and femoral neck fracture. The study population included 10,554 healthy Chinese people (8665 females, 1889 males) aged 20–97 yrs living in Shanghai. Cases were 106 patients (82 females, 24 males) aged 52 yrs old and over with femoral neck fracture. Controls were 106 age-matched healthy persons. All subjects were measured bone mineral density (BMD) at any site of proximal femur and HAL using dual-energy X-ray absorptiometry. HAL had significantly positive correlations with height and weight. After the adjustment of height and weight, HAL increased with age at 50 yrs of age and over in females, and no difference was found among the age groups in males. Males had longer HAL than females in all age groups. The peak BMD appeared in 30–44 yrs for females and 20–24 yrs for males and decreased thereafter, especially for females at 50 yrs old and over. HAL was similar in both fracture and control groups, whereas the BMD values at proximal femur were significantly lower in fracture group than in controls. There was no evidence that subjects with femoral neck fracture had longer HAL. Because of the limitations of retrospective study and relatively small fracture sample, prospective studies are required to determine the conclusions.

We identified 17 polymorphisms in myostatin by sequencing, and three informative single nucleotide polymorphisms (SNPs) were selected for further observation for their association with peak BMD of women in 401 Chinese nuclear families. Our results suggest that genetic polymorphisms in myostatin likely play a role in attainment of peak BMD in Chinese women.Myostatin is a TGF-beta family member that is a negative regulator of skeletal muscle growth.We identified SNPs in myostatin by direct sequencing. Furthermore, using a quantitative transmission disequilibrium test (QTDT). we tested and further test whether SNPs were associated with peak bone mineral density (BMD) variation at the spines and hips of 401 Chinese nuclear families. We identified 17 polymorphisms in myostatin by sequencing. Next, we selected three informative SNPs for further observation of an association with peak BMD of premenopausal women in 401 Chinese nuclear families.Using QTDT for the within-family association, we found significant association between rs2293284 and total hip, femoral neck, and trochanter BMD (all p0.05), while rs7570532 was associated with total hip and trochanter BMD (p = 0.034 and p = 0.035, respectively). The within-family association was significant between BMI and +2278GA (p = 0.022). Subsequent permutations were in agreement with these significant within-family association results. Moreover, analyses of the haplotypes confer further evidence for association of rs2293284 and rs7570532 with hip peak BMD variation.These results suggest, for the first time, the genetic polymorphisms in myostatin likely play a role in attainment of peak BMD in Chinese women.