Zhen-lin Zhang

Association of polymorphisms in low-density lipoprotein receptor-related protein 5 gene with bone mineral density in postmenopausal Chinese women

AbstractAim:To investigate the possible association of Q89R, N740N and A1330V polymorphisms in low-density lipoprotein receptor-related protein 5 (LRP5) gene with bone mineral density (BMD) in postmenopausal Chinese women.Methods:Q89R, N740N and A1330V genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 647 unrelated healthy postmenopausal Han Chinese women aged 43–76 years in Shanghai. BMD at lumbar spine 1–4 and the left proximal femur including the femoral neck, trochanter and Wards triangle were measured by dual-energy X-ray absorptionmetry in all subjects.Results:The distribution of the Q89R, N740N and A1330V genotypes in this population was as follows: QQ 80.5%, QR 18.7%, and RR 0.8%; TT 66.9%, TC31.1%, and CC2.0%; AA 68.0%, AV 29.7%, and VV 2.3%. The frequencies of the Q89R, N740N and A1330V genotypes and alleles did not deviate from the Hardy-Weinberg equilibrium. We found that the Q89R and A1330V polymorphisms were in linkage disequilibrium in our population (χ2=13.50, P<0.01). Both before and after adjusting for age, years since menopause, height, and weight, the Q89R or N740N genotypes were significantly associated with BMD at the femoral neck (P<0.05). Subjects with the Q89R QQ genotype or the N740N TT genotype had a significantly higher BMD at the femoral neck, compared with those with the QR/RR or TC/CC genotypes, respectively. No significant association was found between A1330V polymorphism and BMD at any site.Conclusion:Our findings suggest that the LRP5 gene is a candidate for the genetic determination of BMD in postmenopausal Chinese women.

Hip axis length changes in 10,554 males and females and the association with femoral neck fracture.

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.

Association between VDR and ESR1 gene polymorphisms with bone and obesity phenotypes in Chinese male nuclear families.

AbstractAim: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.Methods: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).Results: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.Conclusion: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.

Age trends for hip geometry in Chinese men and women and the association with femoral neck fracture

SummaryHip dual-energy X-ray absorptiometry (DXA) images were used to calculate hip bone mineral density (BMD) and hip geometry parameters of 18,502 healthy Chinese people (14,435 women and 4,067 men), 254 subjects sustained a femoral neck fracture and 254 age- and sex-matched controls. Our study showed that thinning of the cortical shell and deterioration of the strength index (SI) in femoral neck with aging in both Chinese men and women. SI may be a risk factor for hip fracture in Chinese women.IntroductionThe purpose of this study was to evaluate age-related trends in the hip geometry of healthy Chinese men and women and to examine whether changes in hip geometric parameters is one of the risk factors of hip fracture.MethodsWe recruited 14,435 women and 4,067 men as the study population. There were 254 subjects (216 women, 38 men) who had sustained a femoral neck fracture; 254 age- and sex-matched healthy persons served as controls. Hip DXA images were used to calculate hip BMD and hip geometry parameters, including the hip axis length (HAL), cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), neck–shaft angle (NSA) and femoral SI.ResultsHip BMD, CSMI, CSA and SI showed significantly negative correlations with age. However, after adjustment for height and weight, HAL increased with age, and there was no strong correlation between CSMI and age in either sex. In both genders, hip BMD and CSA were significant lower in fracture cases compared with controls. After adjustment for hip BMD, in women only smaller SI (odds ratio [OR] 1.53; 95% confidence interval [CI], 1.04–2.26) was predictive of hip fracture but in men, none of the geometry parameters was associated with hip fracture risk.ConclusionsThis study demonstrated thinning of the cortical shell and deterioration of the resistance to bending and SI with aging in femoral neck in Chinese men and women. SI may be a risk factor for hip fracture that is independent of BMD measurement in Chinese women.

Identification of the CLCN7 gene mutations in two Chinese families with autosomal dominant osteopetrosis (type II)

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.

Serum osteocalcin levels are inversely associated with plasma glucose and body mass index in healthy Chinese women

Aim:Osteocalcin, a biochemical marker of bone formation, has been suggested to be involved in the regulation of energy metabolism. The aim of this study was to investigate the possible association between serum osteocalcin and markers of glucose and lipid metabolism in a large sample of healthy Chinese women.Methods:A total of 2032 healthy Chinese women in Shanghai, aged 20–94 (including 1396 discovery-study subjects and 636 postmenopausal women for a reduplication analysis) were recruited. Their serum osteocalcin, calcium and the relevant measurements were analyzed. A Spearman correlation analysis was performed between osteocalcin and the other markers of energy metabolism including triglyceride, total cholesterol, fasting plasma glucose (FPG), serum insulin, body mass index and homeostasis model assessment-insulin resistance. Separate multiple regression analyses were performed with data from the discovery and reduplication subjects to determine whether serum osteocalcin concentration was an independent predictor of the glucose or lipid metabolism markers.Results:For the discovery-study subjects, serum osteocalcin was found to be negatively associated with weight (r=−0.08, P=0.002), BMI (−0.13, P<0.001) and FPG (r=−0.13, P=0.001). Similar results were also found in the reduplication subjects (weight: r=−0.19, P=0.016; BMI: r=−0.23, P=0.003; FPG: r=−0.28, P<0.001). In the multiple regression analysis, serum osteocalcin was revealed as a potential independent predictor for FPG (β=−0.07 and –0.210 for discovery and reduplication, respectively, P<0.01) and BMI (β=−0.127 and –0.299 for discovery and reduplication, respectively, P<0.01).Conclusion:Serum osteocalcin is negatively associated with weight BMI and FPG in healthy Chinese women. Therefore, osteocalcin might contribute to obesity and diabetes.

Association between SNP and haplotypes in PPARGC1 and adiponectin genes and bone mineral density in Chinese nuclear families

AbstractAim:To assess the contribution of single nucleotide polymorphisms (SNP) and haplotypes in the peroxisome proliferator-activated receptor-γ co-activator-1 (PPARGC1) and adiponectin genes to normal bone mineral density (BMD) variation in healthy Chinese women and men.Methods:We performed population-based (ANOVA) and family-based (quantitative trait locus transmission disequilibrium test) association studies of PPARGC1 and adiponectin genes. SNP in the 2 genes were genotyped. BMD was measured using dual-energy X-ray absorptiometry in the lumbar spine and hip in 401 nuclear families with a total of 1260 subjects, including 458 premenopausal women, 20–40 years of age; 401 post-menopausal women (mothers), 43–74 years of age; and 401 men (fathers), 49–76 years of age.Results:Significant within-family association was found between the Thr394Thr polymorphism in the PPGAGC1 gene and peak BMD in the femoral neck (P=0.026). Subsequent permutations were in agreement with this significant within-family association result (P=0.016), but Thr394Thr SNP only accounted for 0.7% of the variation in femoral neck peak BMD. However, no significant within-family association was detected between each SNP in the adiponectin gene and peak BMD. Although no significant association was found between BMD and SNP in the PPARGC1 and adiponectin genes in both men and postmenopausal women, haplotype 2 (T-T) in the adiponectin gene was associated with lumbar spine BMD in postmenopausal women (P=0.019).Conclusion:Our findings suggest that Thr394Thr SNP in the PPARGC1 gene was associated with peak BMD in the femoral neck in Chinese women. Confirmation of our results is needed in other populations and with more functional markers within and flanking the PPARGC1 or adiponectin genes region.

No association between polymorphisms of proliferator-activated receptor-gamma gene and peak bone mineral density variation in Chinese nuclear families

SummaryAssociation between SNPs in polymorphism in proliferator-activated receptor-gamma (PPARG) and peak bone mineral density (BMD) variation of women was measured in 401 Chinese nuclear families using quantitative transmission disequilibrium test (QTDT). The peak BMD variation was not attributable to PPARG in our sample.Introduction The purpose of this study is to test whether genetic PPARG might play a role in normal variation in peak BMD.Methods We genotyped 10 tagging SNPs in PPARG using allele-specific polymerase chain reaction and further test whether these SNPs were associated with peak BMD variation at the lumbar spine and femoral neck of women in 401 Chinese nuclear families using QTDT. Furthermore, the association between these SNPs in PPARG and BMD in 710 postmenopausal Chinese women was measured.ResultsUsing QTDT for within-family association, we failed to find that single SNP and haplotype were significantly associated with peak BMD at the lumbar spine and femoral neck. Meanwhile, we found that only rs1801282 was significantly associated with BMD at the lumbar spine in postmenopausal women (P = 0.013).ConclusionsOur present results suggest, for the first time, that the genetic polymorphism in PPARG is not a major contributor to the observed variability in peak BMD at the lumbar spine and femoral neck in Chinese women.

Association of serum 25-hydroxyvitamin D with insulin resistance and β-cell function in a healthy Chinese female population

Aim:To assess associations of the serum level of 25-hydroxyvitamin D with insulin resistance and β-cell function in a healthy Chinese female population.Methods:This cross-sectional study included 1382 female participants free of type 2 diabetes who were recruited in Shanghai. Blood samples were collected within a winter season and the serum levels of 25-hydroxyvitamin D, fasting plasma glucose and insulin, and other biochemical parameters were determined. Insulin resistance and β-cell function were assessed using the homeostasis model assessments of insulin resistance (HOMA-IR) and β-cell function (HOMA-B), respectively.Results:Multiple linear regression analyses adjusted for age, parathyroid hormone, Ca2+ and BMI revealed that independent inverse associations existed between the serum level of 25-hydroxyvitamin D and HOMA-IR (P<0.001) and between the serum level of 25-hydroxyvitamin D and HOMA-B (P=0.001).Conclusion:Serum vitamin D level is significantly and independently associated with insulin resistance and β-cell function in a healthy Chinese female population.

Contribution of Myostatin gene polymorphisms to normal variation in lean mass, fat mass and peak BMD in Chinese male offspring

Aim: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.Methods: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).Results: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<0.001). Moreover, for within-family associations, haplotypes AGG, AAA, and TGG were found to be significantly associated with the trunk fat mass (all P<0.001).Conclusion:Our results suggest that genetic variation within Myostatin may play a role in regulating the variation in fat mass in Chinese males. Additionally, the Myostatin gene may be a candidate that determines body fat mass in Chinese men.