Pharmacokinetic/pharmacodynamic evaluation of gamithromycin against rabbit pasteurellosis.

BACKGROUND: Gamithromycin is an effective therapy for bovine and swine respiratory diseases but not utilized for rabbits. Given its potent activity against respiratory pathogens, we sought to determine the pharmacokinetic profiles, antimicrobial activity and target pharmacokinetic/pharmacodynamic (PK/PD) exposures associated with therapeutic effect of gamithromycin against Pasteurella multocida in rabbits. RESULTS: Gamithromycin showed favorable PK properties in rabbits, including high subcutaneous bioavailability (86.7 ± 10.7%) and low plasma protein binding (18.5-31.9%). PK analysis identified a mean plasma peak concentration (Cmax) of 1.64 ± 0.86 mg/L and terminal half-life (T1/2) of 31.5 ± 5.74 h after subcutaneous injection. For P. multocida, short post-antibiotic effects (PAE) (1.1-5.3 h) and post-antibiotic sub-inhibitory concentration effects (PA-SME) (6.6-9.1 h) were observed after exposure to gamithromycin at 1 to 4× minimal inhibitory concentration (MIC). Gamithromycin demonstrated concentration-dependent bactericidal activity and the PK/PD index area under the concentration-time curve over 24 h (AUC24h)/MIC correlated well with efficacy (R2 > 0.99). The plasma AUC24h/MIC ratios of gamithromycin associated with the bacteriostatic, bactericidal and bacterial eradication against P. multocida were 15.4, 24.9 and 27.8 h in rabbits, respectively. CONCLUSIONS: Subcutaneous administration of 6 mg/kg gamithromycin reached therapeutic concentrations in rabbit plasma against P. multocida. The PK/PD ratios determined herein in combination with ex vivo activity and favorable rabbit PK indicate that gamithromycin may be used for the treatment of rabbit pasteurellosis.

Genetic Polymorphisms of Nuclear Factor-κB Family Affect the Bone Mineral Density Response to Zoledronic Acid Therapy in Postmenopausal Chinese Women.

The aim of this study was to explore the allelic association between genetic polymorphisms of the NF-κB pathway and the variance of clinical effects of zoledronic in postmenopausal Chinese women with osteoporosis. In the study, 110 Chinese postmenopausal women with osteoporosis were recruited. Every patient received zoledronic once a year. BMD was measured at baseline and after one year of treatment. The 13 tagger SNPs of five genes in the NF-κB pathway were genotyped. In the study, 101 subjects completed the one-year follow-up. The ITCTG and DTCTG haplotypes, which are constituted of rs28362491, rs3774937, rs230521, rs230510 and rs4648068 of the NF-κB1 gene, were associated with improvement in BMD at L1-4 and femoral neck (p < 0.001, p = 0.008, respectively). The CGC haplotype, which is constituted of rs7119750, rs2306365 and rs11820062 of the RELA gene, was associated with improvement in BMD at total hip (p < 0.001). After Bonferroni correction, haplotypes ITCTG and CGC still showed significant association with the % change of BMD at L1-4 and total hip. Therefore, NF-κB1 and RELA gene were significantly associated with bone response to the treatment of zoledronic in postmenopausal Chinese women with osteoporosis.

Serum Periostin Level and Genetic Polymorphisms Are Associated with Vertebral Fracture in Chinese Postmenopausal Women.

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.

LGR4 Gene Polymorphisms Are Associated With Bone and Obesity Phenotypes in Chinese Female Nuclear Families.

Objective: The current study was conducted to determine whether peak bone mineral density (BMD) and obesity phenotypes are associated with certain LGR4 gene polymorphisms found in Chinese nuclear families with female children. Methods: A total of 22 single nucleotide polymorphisms (SNPs) located in and around the LGR4 gene were identified in 1,300 subjects who were members of 390 Chinese nuclear families with female children. Then, BMD readings of the femoral neck, total hip, and lumbar spine as well as measurements of the total lean mass (TLM), total fat mass (TFM), and trunk fat mass were obtained via dual-energy X-ray absorptiometry. The quantitative transmission disequilibrium test was used to analyze the associations between specific SNPs and LGR4 haplotypes and peak BMD as well as between LGR4 haplotypes and TLM, percent lean mass, TFM, percent fat mass, trunk fat mass, and body mass index (BMI). Results: Here, rs7936621 was significantly associated with the BMD values for the total hip and lumbar spine, while rs10835171 and rs6484295 were associated with the trunk fat mass and BMI, respectively. Regarding the haplotypes, we found significant associations between GAA in block 2 and trunk fat mass and BMI, between AGCGT in block 3 and total hip BMD, between TGCTCC in block 5 and femoral neck BMD, and between TACTTC in block 5 and both lumbar spine and femoral neck BMD (all P-values < 0.05). Conclusion: Genetic variations of the LGR4 gene are related to peak BMD, BMI, and trunk fat mass.

Association between LGR4 polymorphisms and peak bone mineral density and body composition.

INTRODUCTION: Leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) could affect differentiation of osteoblasts and bone mass through potentiating Wnt/ß-catenin signaling. LGR4 is also relevant to glycolipid metabolism. The present study aims to explore the relationship between genetic variations in LGR4 gene and peak bone mineral density (peak BMD) and body composition phenotypes in Chinese nuclear families. MATERIALS AND METHODS: 22 single-nucleotide polymorphisms (SNPs) were selected and five blocks were constructed in LGR4. Body composition (lean mass and fat mass) and peak BMD were measured by dual-energy X-ray absorptiometry (DXA). Quantitative transmission disequilibrium test (QTDT) analysis was used to explore the relationship between LGR4 genotypes and the mentioned phenotypes. RESULTS: For QTDT analysis after 1000 permutations, significant within-family associations were observed between rs11029986 and total fat mass (TFM) and percentage of TFM (PFM) (P = 0.014 and 0.011, respectively), rs12787344, rs4128868, rs4923445, and rs7936621 and body mass index (BMI) (P = 0.008, 0.003, 0.046, and 0.003, respectively), rs11029986 and total hip BMD (P = 0.026), and rs12796247, rs2219783, and lumbar spine BMD (P = 0.013 and 0.027, respectively). Haplotypes GCGT and AAGC (both in block 3) were observed in significant within-family association with BMI (P = 0.003 and 0.002, respectively). CONCLUSION: It is the first family-based association analysis to explore and demonstrate significant associations between LGR4 genotypes and variations of peak BMD and body composition in young Chinese men. The results are consistent with the findings that recent studies revealed, and confirm the critical relationship between LGR4 gene and both BMD and body composition.

Genetic variants in the PLS3 gene are associated with osteoporotic fractures in postmenopausal Chinese women.

Plastin 3 (PLS3) has been identified as a candidate gene for bone fragility in the Rotterdam study (RS) population. So far, however, whether PLS3 polymorphisms are genetic risk factors for osteoporosis in Asian population remains unclear. In order to investigate the association between genetic variants in PLS3 and the risk of fragility fracture and/or bone mineral density (BMD) in postmenopausal Chinese women, we conducted a case-control association study. A total of 1083 postmenopausal patients with osteoporotic fractures and 2578 unrelated non-fracture controls in Shanghai were enrolled. Seven SNPs, including six tagSNPs in PLS3 and one identified genetic risk factor (rs140121121) for osteoporosis in the RS population, were genotyped in all the participants. BMD at lumbar spine and hip sites were measured in 2578 controls. Association between SNPs and the risk of osteoporotic fractures and/or BMD were analyzed. The GC genotype of rs757124 and AC genotype of rs10521693 were associated with lumbar vertebral fracture (P = 0.020 and 0.046, respectively). The association between tagSNPs and BMD were analyzed only in 2546 controls to avoid biased conclusion. rs757124 was significantly associated with BMD at lumbar spine and hip sites. GG genotype had the highest BMD at lumbar spine (L1-4), while CC genotype had the highest BMD at hip sites. Our results suggest that polymorphisms in PLS3 are genetic loci for osteoporosis in postmenopausal Chinese women.

Whole-Exome Sequencing Identifies Novel Recurrent Somatic Mutations in Sporadic Parathyroid Adenomas.

Primary hyperparathyroidism is commonly caused by excess production of parathyroid hormone from sporadic parathyroid adenomas. However, the genetic architecture of sporadic primary hyperparathyroidism remains largely uncharacterized, especially in the Chinese population. To identify genetic abnormalities that may be involved in the etiology of sporadic parathyroid adenomas and to determine the mutation frequency of previously identified genes in the Chinese population, we performed whole-exome sequencing of 22 blood-tumor pairs from sporadic parathyroid adenomas. The most important finding is the recurrently mutated gene, ASXL3, which has never been reported in parathyroid tumors before. Moreover, we identified two different somatic mutations in the CDC73 gene and one somatic mutation in the EZH2 gene. The Y54X mutation in the CDC73 gene was previously identified in parathyroid carcinomas, which proved that parathyroid adenomas and carcinomas might possess similar molecular signatures. No mutations in the MEN1 or CCND1 genes were observed in our study. Thus, our data provide insights into the genetic pathogenesis of sporadic parathyroid adenomas and are valuable for the development of diagnostic and therapeutic approaches for sporadic primary hyperparathyroidism.

Novel mutations of TCIRG1 cause a malignant and mild phenotype of autosomal recessive osteopetrosis (ARO) in four Chinese families.

Human autosomal recessive osteopetrosis (ARO), also known as infantile malignant osteopetrosis, is a rare genetic bone disorder that often causes death. Mutations in T-cell immune regulator 1 (TCIRG1) are a frequent cause of human ARO. Six additional genes (TNFSF11, TNFRSF11A, CLCN7, OSTM1, SNX10, PLEKHM1) were also found to be associated with human ARO. In order to expand the mutation spectrum and clinical diversity for a better understanding of the ARO phenotype and to further investigate the clinical characteristics of benign subjects with ARO, we here report five individuals with ARO from four unrelated Chinese families. X-ray examination was conducted and bone turnover markers were assayed. The gene of T-cell immune regulator 1 (TCIRG1) was screened and analyzed. Monocyte-induced osteoclasts were prepared and their resorption ability was studied in vitro. We identified five novel mutations (c.66delC, c.1020+1_1020+5dup, c.2181C>A, c.2236+6T>G, c.692delA) in these patients. Four patients displayed a malignant phenotype, three of them died, and one who received bone marrow transplantation survived. The remaining one, a 24-year-old male from a consanguineous family, was diagnosed based on radiological findings but presented no neurological or hematological defects. He was homozygous for c.2236+6T>G in intron 18; this mutation influenced the splicing process. An in vitro functional study of this novel splicing defect showed no resorption pits on dentine slices. TCIRG1-dependent osteopetrosis with a mild clinical course was observed for the first time in Chinese population. The present findings add to the wide range of phenotypes of Chinese patients with TCIRG1-dependent ARO and enrich the database of TCIRG1 mutations.

Clinical, Biochemical, and Genetic Features of 41 Han Chinese Families With Primary Hypertrophic Osteoarthropathy, and Their Therapeutic Response to Etoricoxib: Results From a Six-Month Prospective Clinical Intervention.

Primary hypertrophic osteoarthropathy (PHO) is a rare inherited disease caused by genetic defects in the prostaglandin metabolism pathway; disturbed prostaglandin E2 (PGE2 ) catabolism resulting in increased PGE2 level is suggested in the pathogenesis. Forty-three Han Chinese patients with PHO were studied and 41 of them were treated. Mutations in the HPGD gene, causing hypertrophic osteoarthropathy, primary, autosomal recessive 1 (PHOAR1; OMIM 259100), were identified in seven patients, and mutations in the SLCO2A1 gene, causing hypertrophic osteoarthropathy, primary, autosomal recessive 2 (PHOAR2; OMIM 614441), were identified in 36 patients. Clinical phenotypes of PHO varied, ranging from mild isolated finger clubbing to severe pachydermia and disabling joint swelling, even within families. Circulating PGE2 metabolism features of PHOAR2 were different from those of PHOAR1. Different frequency and severity of pachydermia between the subgroups were also indicated. A percentage of PHOAR2 patients suffered from gastrointestinal hemorrhage, but this symptom was not observed in the PHOAR1 subgroup. Clinical evidence highlighted the essential role of sex hormones in prostaglandin transporter regulation with respect to PHOAR2 onset, although no significant associations of urinary PGE2 or PGE-M with sex hormones were identified. Treatment with etoricoxib, a selective cyclooxygenase-2 inhibitor, was proved to be beneficial and safe. We detected its notable efficacy in decreasing urinary PGE2 levels in the majority of the enrolled patients during 6 months of intervention; clinical phenotypes assessed, including pachydermia, finger clubbing, and joint swelling, were improved. We found no visible evidence of a positive effect of etoricoxib on periostosis; however, significant links between urinary PGE2 and serum bone turnover markers indicated a potential role of decreased PGE2 in periostosis management. This is the largest reported cohort of subjects genetically diagnosed with PHO. For the first time, we systematically investigated the biochemical and clinical differences between PHOAR1 and PHOAR2, and prospectively showed the positive efficacy and safety of etoricoxib for PHO patients. © 2017 American Society for Bone and Mineral Research.

Reports of 17 Chinese patients with tumor-induced osteomalacia.

Tumor-induced osteomalacia (TIO) is a rare acquired form of hypophosphatemic osteomalacia, which is usually attributed to the overproduction of fibroblast growth factor 23 (FGF-23) by benign mesenchymal neoplasms. Localization and thereafter surgical resection of tumors lead to a cure. The present study aimed to investigate the clinical data, diagnostic methods, and follow-up after tumor resection at one medical center in Shanghai to characterize the profile of this rare disorder and to share our successful experience in diagnosis and treatment. Twenty-three patients with adult-onset hypophosphatemia osteomalacia seen in Shanghai Sixth People's Hospital from 2009 to 2014 and 95 normal individuals were enrolled. After taking a medical history and performing a physical examination, we analyzed the laboratory results (including the serum FGF-23 levels) and localized the tumors by 18F-fluorodeoxyglucose positron emission tomography and computed tomography (18F-FDG PET/CT), 99mTc-octreotide (99mTc-OCT) scintigraphy, and magnetic resonance imaging (MRI). On the basis of the results of laboratory tests and imaging findings, tumor resection was conducted in 17 patients with a certain diagnosis of TIO. The results demonstrated that the 17 patients (nine men and eight women, average age 46.6 ± 12.9 years) had TIO. FGF-23 level was elevated in 94.1 % of patients (16 of 17 patients) . Serum phosphorus level decreased in 100 % of patients. 18F-FDG PET/CT revealed five tumors, 99mTc-OCT scintigraphy revealed two tumors, physical examination revealed nine tumors, and MRI revealed one tumor, among which 58.8 % of the causative tumors (10 of 17 tumors) were located in the lower extremities. After tumor resection, serum phosphorus levels normalized in 100 % of patients (all 17 patients) in 4-21 days and FGF-23 levels decreased in 90 % of patients (nine of ten patients). We found 64.7 % of the tumors (11 of 17 tumors) were phosphaturic mesenchymal tumors or a phosphaturic mesenchymal tumor mixed connective tissue variant. Measurement of serum phosphorus and FGF-23 levels in patients with suspected TIO is of paramount importance for diagnosing of TIO. 18F-FDG PET/CT, 99mTc-OCT scintigraphy, and physical examination play a considerable role in revealing TIO-associated tumors. TIO-associated tumors were more frequently located in the lower extremities than in other places; thus, the lower extremities need to be carefully checked. Complete surgical resection results in normalization of parameters in laboratory tests and relief of symptoms of TIO patients.

Association between SNPs and haplotypes in the METTL21C gene and peak bone mineral density and body composition in Chinese male nuclear families.

The methyltransferase-like 21C gene (METTL21C), which is mainly expressed in muscle, can promote the differentiation of myoblasts to myotubes and reduce glucocorticoid-induced apoptosis of osteocytes. The purpose of this study was to explore the association between single nucleotide polymorphisms of METTL21C and peak bone mineral density (BMD), body mass index, total fat mass (TFM), and total lean mass (TLM) in Chinese young men. Fifteen tagging single nucleotide polymorphisms were genotyped, and haplotype blocks were derived in 400 Chinese male nuclear families. The peak BMD of the lumbar and hip, TFM, and TLM were measured by dual-energy X-ray absorptiometry. The association analyses were performed by a quantitative transmission disequilibrium test. Both TLM and TFM had a significant positive effect on peak BMD, but the positive regulation of TLM was stronger than that of TFM. After 1000 permutations, significant within-family associations were found between rs9585961 and lumbar spine BMD and femoral neck BMD, rs9518810 and femoral neck BMD, and rs599976 and body mass index, TFM, and percentage fat mass (all P < 0.05). The association analyses with haplotypes showed that haplotype AG in block 1 was significantly associated with TFM (P = 0.031) and haplotype CAG in block 2 was significantly associated with lumbar spine BMD (P = 0.020). Our study, for the first time, demonstrates that the polymorphisms and haplotypes of METTL21C contribute to the peak BMD and TFM in Chinese males, which suggests that as a quantitative trait locus with potential pleiotropy it may have an influence on osteoporosis and obesity.

Associations of Serum Osteocalcin and Polymorphisms of the Osteocalcin Gene with Bone Mineral Density in Postmenopausal and Elderly Chinese Women.

BACKGROUND: The aims of this study were: (1) to evaluate the association of serum osteocalcin with bone mineral density (BMD) and markers of bone metabolism in postmenopausal and elderly Chinese women, and (2) to observe the relationships of single-nucleotide polymorphisms (SNPs) in and around the osteocalcin gene with osteocalcin and BMD. METHODS: A cross-sectional study was conducted with 725 postmenopausal Chinese women. Five SNPs (rs1543294, rs1800247, rs759330, rs2842880, and rs933489) of the osteocalcin gene were genotyped. Serum osteocalcin and intact parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], and type I collagen containing cross-linked C-telopeptide (ß-CTX) were measured. The BMD of the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry. RESULTS: Osteocalcin was positively correlated with serum phosphorus (p = 0.001), alkaline phosphatase (ALP; p < 0.001), PTH (p = 0.002) and ß-CTX (p < 0.001), and negatively correlated with BMD at the lumbar spine (p < 0.001) and total hip (p = 0.002). No significant association was obtained between the SNPs, haplotypes of the osteocalcin gene, and BMD or osteocalcin. CONCLUSION: Our results suggest that osteocalcin was positively correlated with serum phosphorus, ALP, PTH, and ß-CTX, but negatively correlated with BMD at the lumbar spine and total hip. Common genetic variants of the osteocalcin gene may not be a major contributor to variations in serum osteocalcin or BMD in postmenopausal and elderly Chinese women.

Seven novel and six de novo PHEX gene mutations in patients with hypophosphatemic rickets.

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.

Genetically Low Vitamin D Levels, Bone Mineral Density, and Bone Metabolism Markers: a Mendelian Randomisation Study.

Low serum 25-hydroxyvitamin D (25OHD) is associated with osteoporosis and osteoporotic fracture, but it remains uncertain whether these associations are causal. We conducted a Mendelian randomization (MR) study of 1,824 postmenopausal Chinese women to examine whether the detected associations between serum 25OHD and bone mineral density (BMD) and bone metabolism markers were causal. In observational analyses, total serum 25OHD was positively associated with BMD at lumbar spine (P = 0.003), femoral neck (P = 0.006) and total hip (P = 0.005), and was inversely associated with intact parathyroid hormone (PTH) (P = 8.18E-09) and procollagen type 1 N-terminal propeptide (P1NP) (P = 0.020). By contract, the associations of bioavailable and free 25OHD with all tested outcomes were negligible (all P > 0.05). The use of four single nucleotide polymorphisms, GC-rs2282679, NADSYN1-rs12785878, CYP2R1-rs10741657 and CYP24A1-rs6013897, as candidate instrumental variables in MR analyses showed that none of the two stage least squares models provided evidence for associations between serum 25OHD and either BMD or bone metabolism markers (all P > 0.05). We suggest that after controlling for unidentified confounding factors in MR analyses, the associations between genetically low serum 25OHD and BMD and bone metabolism markers are unlikely to be causal.

Osteomalacia induced by long-term low-dose adefovir dipivoxil: Clinical characteristics and genetic predictors.

CONTEXT: Adefovir dipivoxil (ADV) was an important cause of adult-onset hypophosphatemic osteomalacia. However, its clinical characteristics and mechanisms have not been well defined. OBJECTIVE: The objective of the study was to summarize the clinical characteristics of ADV-induced osteomalacia and to explore the association between ADV-associated tubulopathy and polymorphisms in genes encoding drug transporters. DESIGN, SETTING, PATIENTS, AND MAIN OUTCOME MEASURE: Seventy-six affected patients were clinically studied. The SLC22A6 and ABCC2 genes were screened and compared with healthy people from the HapMap. RESULTS: Hypophosphatemia, high serum alkaline phosphatase (ALP) levels, hypouricemia, nondiabetic glycosuria, proteinuria, metabolic acidosis and high bone turnover markers were the main metabolic characteristics. Fractures and pseudofractures occurred in 39 patients. Stopping ADV administration, supplementing calcitriol and calcium was effective during the follow-up period. Single SNP analysis revealed a higher percentage of the G/A genotype at c.2934 in exon 22 of the ABCC2 gene (rs3740070) in patients than in healthy people (12% [7 of 58 patients] vs. 0% [0 of 45 patients]; P=0.017), while there was no subject with homozygosity for the A allele at c.2934. CONCLUSIONS: ADV can be nephrotoxic at a conventional dosage. The G/A genotype at c.2934 of the ABCC2 gene may be a predictor of patients at greater risk for developing ADV-associated tubulopathy. Larger case-control studies are needed to further verify this finding.

Identification of two novel mutations in the COMP gene in six families with pseudoachondroplasia.

Pseudoachondroplasia (PSACH; MIM no. 177170) is an autosomal dominant osteochondrodysplasia characterized by short­limb short stature, brachydactyly and early­onset osteoarthropathy. Typically, at approximately two years of age, the rate of growth falls below the standard growth curve, causing a moderately severe form of disproportionate short­limb short stature. The current study described the clinical and radiographic observations of six Chinese patients with PSACH, and identified two de novo novel missense mutations [p.Asp326Asn (c.976G>A) and c.1585A>G (p.Thr529Ala)] in cartilage oligomeric matrix protein (COMP) in the patients. The current study expanded the mutation spectrum of the COMP gene, and contributes to the understanding of phenotype/genotype of COMP­associated diseases.

BMP7 gene polymorphisms are not associated with bone mineral density or osteoporotic fractures in postmenopausal Chinese women.

AIM: A previous study shows that bone morphogenetic protein 7 (BMP7) gene polymorphisms are associated with bone mineral density (BMD) in 920 European Americans. To determine the association of BMP7 polymorphisms and BMD and osteoporotic fracture susceptibility, we performed a case-control association study in postmenopausal Chinese women with or without osteoporotic fracture. METHODS: A total of 3815 unrelated postmenopausal Chinese women (1238 with osteoporotic fracture and 2577 healthy controls) were recruited. BMDs of the lumbar spine 1-4 (L1-4) and proximal femur (including total hip and femoral neck) were measured using dual-energy X-ray absorptiometry. Eight tagging single nucleotide polymorphisms (SNPs) in BMP7 gene, including rs11086598, rs4811822, rs12481628, rs6025447, rs230205, rs17404303, rs162316 and rs6127980, were genotyped. RESULTS: Among the 8 SNPs, rs6025447 and rs230205 were associated with total hip BMD (P=0.013 and 0.045, respectively). However, the associations became statistically insignificant after adjusting for age, height and weight. The TGTG haplotype of BMP7 gene was associated with total hip BMD (P=0.032), even after adjusting for age, height and weight (P=0.048); but the association was insignificant after performing the Bonferroni multiple-significance-test correction. Moreover, the 8 SNPs and 9 haplotypes of BMP7 gene were not associated with L1-4 or femoral neck BMD or osteoporotic fracture. CONCLUSION: This large-sample case-control association study suggests that the common genetic polymorphisms of BMP7 gene are not major contributors to variations in BMD or osteoporotic fracture in postmenopausal Chinese women.

Two novel mutations of CLCN7 gene in Chinese families with autosomal dominant osteopetrosis (type II).

Autosomal dominant osteopetrosis type II (ADO-II) is a heritable bone disorder characterized by osteosclerosis, predominantly involving the spine (vertebral end-plate thickening, or rugger-jersey spine), the pelvis ("bone-within-bone" structures) and the skull base. Chloride channel 7 (CLCN7) has been reported to be the causative gene. In this study, we aimed to identify the pathogenic mutation in four Chinese families with ADO-II. All 25 exons of the CLCN7 gene, including the exon-intron boundaries, were amplified and sequenced directly in four probands from the Chinese families with ADO-II. The mutation site was then identified in other family members and 250 healthy controls. In family 1, a known missense mutation c.296A>G in exon 4 of CLCN7 was identified in the proband, resulting in a tyrosine (UAU) to cysteine (UGU) substitution at p.99 (Y99C); the mutation was also identified in his affected father. In family 2, a novel missense mutation c.865G>C in exon 10 was identified in the proband, resulting in a valine (GUC) to leucine (CUC) substitution at p.289 (V289L); the mutation was also identified in her healthy mother and sister. In family 3, a novel missense mutation c.1625C>T in exon 17 of CLCN7 was identified in the proband, resulting in an alanine (GCG) to valine (GUG) substitution at p.542 (A542V); the mutation was also identified in her father. In family 4, a hot spot, R767W (c.2299C>T, CGG>TGG), in exon 24 was found in the proband which once again proved the susceptibility of the site or the similar genetic background in different races. Moreover, two novel mutations, V289L and A542V, occurred at a highly conserved position, found by a comparison of the protein sequences from eight vertebrates, and were predicted to have a pathogenic effect by PolyPhen-2 software, which showed "probably damaging" with a score of approximately 1. These mutation sites were not identified in 250 healthy controls. Our present findings suggest that the novel missense mutations V289L and A542V in the CLCN7 gene were responsible for ADO-II in the two Chinese families.

OPG, RANKL, and RANK gene polymorphisms and the bone mineral density response to alendronate therapy in postmenopausal Chinese women with osteoporosis or osteopenia.

OBJECTIVE: The aim of the study was to explore the association between OPG, RANKL, and RANK gene variations and the bone mineral density (BMD) response to alendronate therapy in postmenopausal Chinese women with osteoporosis or osteopenia. MATERIALS AND METHODS: In the present study, 40 single-nucleotide polymorphisms (SNPs) in the OPG, RANKL, and RANK genes were genotyped in 501 postmenopausal Chinese women with osteoporosis or osteopenia who were given alendronate (70 mg weekly) orally for 1 year. The BMD at the lumbar spine 1-4 (L1-L4), femoral neck, and total hip was measured. RESULTS: A total of 442 patients completed 1 year of alendronate therapy. The rs7239261 SNP of the RANK gene was significantly associated with baseline L1-L4 BMD (P=0.0004) after correction for age and BMI. Participants with the SNP A allele (C/A and A/A) had a higher BMD than those with the C/C genotype (C/A vs. C/C, P=0.001; A/A vs. C/C, P=0.025). Haplotypes AG of rs7239261-rs12969154, GG of rs3826619-rs11877530, and CACG of rs1805034-rs8083511-rs17069895-rs7231887 in the RANK gene were genetic protective factors toward a higher baseline L1-L4 BMD. No association was observed between any SNP or haplotype of the OPG, RANKL, and RANK genes and the response of BMD to alendronate therapy. CONCLUSION: The RANK gene might contribute to genetic variability in L1-L4 BMD in postmenopausal Chinese women with osteoporosis or osteopenia. No evidence of an association between any SNP or haplotype of the OPG, RANKL, and RANK genes and the response of BMD to alendronate therapy was found in postmenopausal Chinese women with osteoporosis or osteopenia.

Calcification of joints and arteries: second report with novel NT5E mutations and expansion of the phenotype.

Calcification of joints and arteries (CALJA; MIM 211800) is an extremely rare mendelian disorder of isolated calcification that is characterized by late onset calcification of the extremity arteries and hand and foot joint capsules. Mutations of NT5E, encoding cluster of differentiation 73, have been implicated in CALJA. Here we report on a Chinese family with CALJA and novel compound heterozygous mutations (c.1360G>A (p.Gly454Arg) and c.1387C>T (p.Arg463X)) in NT5E. Our study represents the second report on patients with CALJA associated with NT5E mutations. The clinical features expand the previously reported phenotype of NT5E mutations. The propositus has calcification of the lower extremity arteries and hand and foot joint capsules similar to those previously reported patients. However, he also has calcification of the upper extremity arteries. By protein structural modeling, we found the mutation p.Gly454Arg may disrupt the folding of ß-pleated sheet and destabilize the protein structure. Our findings will provide clues to the phenotype-genotype relations and may assist not only in the clinical diagnosis but also in the interpretation of genetic information used for prenatal diagnosis and genetic counseling.