The -1997 G/T polymorphism in the COLIA1 upstream regulatory region is associated with hip bone mineral density (BMD) in Chinese nuclear families

Association of COL1A1 polymorphism with subchondral bone degeneration of the temporomandibular joint

The G/T polymorphism of the COL1A1 gene exhibits a clinically significant influence on bone remodelling, leading to a predisposition to degenerative diseases. The enhancement of bone turnover and further loss of bone mass are thought to be the primary pathological changes in the early degenerative course of temporomandibular joint osteoarthritis (TMJ OA), with the appearance of low-density lesions. Thus, it was hypothesized that this polymorphism may also affect this type of bone lesion in TMJ OA. A total of 130 TMJ OA patients with low-density lesions (cortical bone erosion, condylar head resorption, cyst-like lesion) and 186 healthy individuals were recruited. DNA samples were extracted from buccal mucosa swabs; genotyping was performed by high-resolution melting assay. The distribution of genotypes in these groups was compared using a multivariate logistic regression model. No significant differences in the distributions of TT and TG genotypes were observed between the groups (P>0.05). Significance was detected for GG homozygous carriers (P=0.043); this genotype might be a risk factor for this type of low-density lesion (odds ratio 1.643, 95% confidence interval 1.016-2.658). This study indicates that the GG genotype might be a risk factor for low-density lesions in the TMJ.

JAG1 and COL1A1 polymorphisms and haplotypes in relation to bone mineral density variations in postmenopausal Mexican-Mestizo Women

Osteoporosis is characterized by low bone mineral density (BMD). One of the most important factors that influence BMD is the genetic contribution. The collagen type 1 alpha 1 (COL1A1) and the JAGGED (JAG1) have been investigated in relation to BMD. The aim of this study was to investigate the possible association between two single-nucleotide polymorphisms (SNPs) of COL1A1, their haplotypes, and one SNP of JAG1 with BMD in postmenopausal Mexican-Mestizo women. Seven hundred and fifty unrelated postmenopausal women were included. Risk factors were recorded and BMD was measured in lumbar spine, total hip, and femoral neck by dual-energy X-ray absorptiometry. DNA was obtained from blood leukocytes. Two SNPs in COL1A1 (rs1800012 and rs1107946) and one in JAG1 (rs2273061) were studied. Real-time PCR allelic discrimination was used for genotyping. The differences between the means of the BMDs according to genotype were analyzed with covariance. Deviations from Hardy-Weinberg equilibrium were tested. Pairwise linkage disequilibrium between single nucleotide polymorphisms was calculated by direct correlation r (2), and haplotype analysis of COL1A1 was conducted. Under a dominant model, the rs1800012 polymorphism of the COL1A1 showed an association with BMD of the lumbar spine (P = 0.021). In addition, analysis of the haplotype of COL1A1 showed that the G-G haplotype presented a higher BMD in lumbar spine. We did not find an association between the s1107946 and rs2273061 polymorphisms of the COL1A1 and JAG1, respectively. Our results suggest that the rs1800012 polymorphism of the COL1A1, in addition to one haplotype, were significantly associated with BMD variation in Mexican-Mestizo postmenopausal women.

Gene variants within the COL1A1 gene are associated with reduced anterior cruciate ligament injury in professional soccer players

OBJECTIVES

To examine the association of the COL1A1 -1997G/T and +1245G/T polymorphisms, individually and as haplotypes, with anterior cruciate ligament ruptures in professional soccer players.

DESIGN

Subjects were 91 male professional soccer players with surgically diagnosed primary anterior cruciate ligament ruptures. The control group consisted of 143 apparently healthy male professional soccer players, who were without any self-reported history of ligament or tendon injury. Both subjects and healthy controls are from the same soccer teams, of the same ethnicity (Polish, East-Europeans for ≥3 generations), a similar age category, and had a comparable level of exposure to anterior cruciate ligament injury.

METHODS

Genomic DNA was extracted from the oral epithelial cells using GenElute Mammalian Genomic DNA Miniprep Kit (Sigma, Germany). All samples were genotyped using a Rotor-Gene real-time polymerase chain reaction.

RESULTS

Genotype distributions for both polymorphisms met the Hardy-Weinberg expectations in both subjects and controls (p>0.05). Higher frequency of the COL1A1 G-T (-1997G/T and +1245G/T polymorphisms) haplotype was significantly associated with reduced risk for anterior cruciate ligament rupture (Hap.score -1.98, p=0.048). The TT genotype was under-represented in the anterior cruciate ligament rupture group. However, this result was not statistically significant (p=0.084 Fisher's exact test, recessive mode: TT vs GT+GG).

CONCLUSIONS

Higher frequency of the COL1A1 G-T haplotype is associated with reduced risk of anterior cruciate ligament injury in a group of professional soccer players. Consequently, carrying two copies the COL1A1 G-T haplotype may be protective against anterior cruciate ligament injury.

Effects of COLIA1 polymorphisms and haplotypes on perimenopausal bone mass, postmenopausal bone loss and fracture risk

One thousand seven hundred seventeen perimenopausal women from the Danish Osteoporosis Prevention Study were genotyped for the -1997G/T, -1663indelT and +1245G/T polymorphisms in the COLIA1 gen. We found that the -1997T allele and a haplotype containing it were associated with reduced bone mineral density (BMD) and increased bone turnover at menopause and after 10 years of follow-up.

INTRODUCTION

We wanted to investigate whether the -1997G/T, -1663indelT and +1245G/T polymorphisms in the COLIA1 gene are associated with perimenopausal bone mass, early postmenopausal bone loss and interact with hormone treatment.

METHODS

One thousand seven hundred seventeen perimenopausal women from the Danish Osteoporosis Prevention Study were genotyped, and haplotypes were determined. BMD was examined by dual X-ray absorptiometry.

RESULTS

Women carrying the -1997T variant had lower BMD at all measured sites: lumbar spine BMD 1.030 ± 0.137 g/cm(2), 1.016 ± 0.147 g/cm(2) and 0.988 ± 0.124 g/cm(2) in women with the GG, GT and TT genotypes, respectively (p < 0.05) and total hip BMD 0.921 ± 0.116 g/cm(2), 0.904 ± 0.123 g/cm(2) and 0.887 ± 0.109 g/cm(2) in women with the GG, GT and TT genotypes, respectively (p = 0.01). The effect remained after 10 years although statistical significance was lost. Haplotype 3 (-1997T-1663ins + 1245G) was associated with lower bone mass and higher levels of bone turnover. Compared with haplotype 1, haplotype 3 carriers had lower BMD at the lumbar spine, femoral neck and total hip by 0.016 ± 0.007 g/cm(2), 0.015 ± 0.006 g/cm(2) and 0.017 ± 0.006 g/cm(2), respectively (p < 0.05-0.005). No association with postmenopausal changes in bone mass and fracture risk and no overall interaction with the effects of hormone therapy could be demonstrated for any of the polymorphisms in COLIA1.

CONCLUSIONS

The -1997G/T polymorphism and haplotype 3 are significantly associated with perimenopausal bone mass, and these effects were sustained up to 10 years after menopause. No association between the -1663indelT or +1245G/T polymorphisms and peri- or postmenopausal bone mass could be demonstrated.

Genetics of osteoporosis: accelerating pace in gene identification and validation

Osteoporosis is characterized by low bone mineral density and structural deterioration of bone tissue, leading to an increased risk of fractures. It is the most common metabolic bone disorder worldwide, affecting one in three women and one in eight men over the age of 50. In the past 15 years, a large number of genes have been reported as being associated with osteoporosis. However, only in the past 4 years we have witnessed an accelerated pace in identifying and validating osteoporosis susceptibility loci. This increase in pace is mostly due to large-scale association studies, meta-analyses, and genome-wide association studies of both single nucleotide polymorphisms and copy number variations. A comprehensive review of these developments revealed that, to date, at least 15 genes (VDR, ESR1, ESR2, LRP5, LRP4, SOST, GRP177, OPG, RANK, RANKL, COLIA1, SPP1, ITGA1, SP7, and SOX6) can be reasonably assigned as confirmed osteoporosis susceptibility genes, whereas, another >30 genes are promising candidate genes. Notably, confirmed and promising genes are clustered in three biological pathways, the estrogen endocrine pathway, the Wnt/beta-catenin signaling pathway, and the RANKL/RANK/OPG pathway. New biological pathways will certainly emerge when more osteoporosis genes are identified and validated. These genetic findings may provide new routes toward improved therapeutic and preventive interventions of this complex disease.

Promoter and intron 1 polymorphisms of COL1A1 interact to regulate transcription and susceptibility to osteoporosis

Three polymorphisms (-1997G/T; -1663IndelT and +1245G/T) have been identified in the 5' flank of COL1A1 gene that are associated with osteoporosis but the underlying mechanism is unclear. Here we investigated the functional effects of these variants on COL1A1 transcription. Transcription was 2-fold higher with the osteoporosis-associated G-del-T haplotype compared with the common G-Ins-G haplotype. Gel shift assays showed that the region surrounding the -1663IndelT polymorphism recognized a complex of proteins essential for osteoblast differentiation and function including Nmp4 and Osterix, and the osteoporosis-associated -1663delT allele had increased binding affinity for this complex. Chromatin immunoprecipitation assays confirmed that the region flanking -1663insdelT bound a complex of proteins including Osterix and Nmp4 and also showed evidence of recruitment of Nmp4 to the Sp1 binding site in intron 1. Further studies showed that haplotype G-del-T had higher binding affinity for RNA polymerase II, consistent with increased transcription of the G-del-T allele and there was a significant inverse association between carriage of G-del-T and bone mineral density (BMD) in a cohort of 3270 Caucasian women. We conclude that common polymorphic variants in the 5' flank of COLIA1 regulate transcription by affecting DNA-protein interactions and that increased levels of transcription correlate with reduced BMD values in vivo. This is consistent with a model whereby increased COL1A1 transcription predisposes to osteoporosis, probably by increasing production of the alpha 1 chain and disrupting the normal ratio of collagen type 1 alpha 1 and alpha 2 chains.

Haplotypes of promoter and intron 1 polymorphisms in the COLIA1 gene are associated with increased risk of osteoporosis

Osteoporosis is a common age-related disease with a strong genetic influence. COLIA1 is one of the most extensively studied candidate genes and has consistently been associated with BMD and fracture. We examined the effects of the polymorphisms -1997G>T, -1663indelT, and +1245G>T and their haplotypes on vertebral fractures and bone mineral density (BMD) in a case-control study comprising 462 osteoporotic patients and 336 controls. The -1663indelT polymorphism was associated with a decreased lumbar spine (ls) BMD, 0.75 +/- 0.14 g/cm(2), in individuals with the del/del genotype versus 0.83 +/- 0.18 and 0.85 +/- 0.18 g/cm(2) in individuals with the ins/del and ins/ins genotypes, respectively (p = 0.02). The T-allele of the +1245G>T polymorphism, which was in strong linkage disequilibrium (LD) with -1663indelT, was also associated with a decreased lsBMD (p = 0.02). -1997G>T was not significantly associated with lsBMD. The three most common haplotypes accounted for 98.5% of the alleles. Individuals with one or two copies of haplotype 1 (-1997G/-1663ins/+1245G) had a significantly higher lsBMD, 0.84 +/- 0.18 and 0.85 +/- 0.15 g/cm(2), respectively, versus 0.78 +/- 0.15 g/cm(2) in noncarriers (p = 0.01). Individuals with two copies of haplotype 2 (-1997G/-1663del/+1245T) had a significantly lower lsBMD, 0.76 +/- 0.14 g/cm(2), versus 0.85 +/- 0.18 and 0.82 +/- 0.18 g/cm(2), respectively, in individuals with zero or one copy (p = 0.03). The odds ratio for vertebral fracture in individuals carrying the variant T-allele of the -1997G>T polymorphism was 1.49 (CI, 1.03-2.16; p = 0.03). Logistic regression revealed that this effect was partly independent of BMD. In conclusion, the -1663del and +1245T alleles influence BMD negatively, whereas the -1997T-allele has a minor effect on BMD but increases the risk of vertebral fractures. These findings are in agreement with functional studies showing that these polymorphisms influence gene expression.

The bare bones of race

In this paper I examine claims of racial difference in bone density and find that the use and definitions of race in medicine lack a theoretical foundation. My central argument is that the social produces the biological in a system of constant feedback between body and social experience. By providing a different angle of vision on claimed racial differences I hope to move the conversation away from an ultimately futile discussion of nature versus nurture, where time is held constant and place seen as irrelevant, and begin to build a new paradigm for examining the contributions of geographic ancestry, individual lifecycle experience, race, and gender to varied patterns of health and disease.

Genetics of osteoporosis

Osteoporosis is a common disease with a strong genetic component characterised by reduced bone mass and an increased risk of fragility fractures. Twin and family studies have shown that genetic factors contribute to osteoporosis by influencing bone mineral density (BMD), and other phenotypes that are associated with fracture risk, although the heritability of fracture itself is modest. Linkage studies have identified several quantitative trait loci that regulate BMD but most causal genes remain to be identified. In contrast, linkage studies in monogenic bone diseases have been successful in gene identification, and polymorphisms in many of these genes have been found to contribute to the regulation of bone mass in the normal population. Population-based studies have identified polymorphisms in several candidate genes that have been associated with bone mass or osteoporotic fracture, although individually these polymorphisms only account for a small amount of the genetic contribution to BMD regulation. Environmental factors such as diet and physical activity are also important determinants of BMD, and in some cases specific nutrients have been found to interact with genetic polymorphisms to regulate BMD. From a clinical standpoint, advances in knowledge about the genetic basis of osteoporosis are likely to be important in increasing the understanding of the pathophysiology of the disease; providing new genetic markers with which to assess fracture risk and in identifying genes and pathways that form molecular targets for the design of the next generation of drug treatments.

Genetics and osteoporosis

Over the past 10 years, many advances have been made in understanding the mechanisms by which genetic factors regulate susceptibility to osteoporosis. It has become clear from studies in man and experimental animals that different genes regulate BMD at different skeletal sites and in men and women. Linkage studies have identified several chromosomal regions that regulate BMD, but only a few causative genes have been discovered so far using this approach. In contrast, significant advances have been made in identifying the genes that cause monogenic bone diseases, and polymorphic variation is some of these genes has been found to contribute to the genetic regulation of BMD in the normal population. Other genes that have been investigated as possible candidates for susceptibility to osteoporosis because of their role in bone biology, such as vitamin D, have yielded mixed results. Many candidate gene association studies have been underpowered, and meta-analysis has been used to try to confirm or refute potential associations and gain a better estimate of their true effect size in the population. Most of the genetic variants that confer susceptibility to osteoporosis remain to be discovered. It is likely that new techniques such as whole-genome association will provide new insights into the genetic determinants of osteoporosis and will help to identify genes of modest effect size. From a clinical standpoint, genetic variants that are found to predispose to osteoporosis will advance our understanding of the pathophysiology of the disease. They could be developed as diagnostic genetic tests or form molecular targets for design of new drugs for the prevention and treatment of osteoporosis and other bone diseases.

COL1A1, ESR1, VDR and TGFB1 polymorphisms and haplotypes in relation to BMD in Spanish postmenopausal women

INTRODUCTION AND HYPOTHESIS

Genetic studies of osteoporosis have focused on analysing single polymorphisms in individual genes - with inconclusive results. An alternative approach may involve haplotypes and gene-gene interactions. The aim of the study was to test the association between the COL1A1, ESR1, VDR and TGFB1 polymorphisms or haplotypes and bone mineral density (BMD) in Spanish postmenopausal women.

METHODS

Sixteen polymorphisms were analysed in 719 postmenopausal women. ANOVA, ANCOVA and Xi2 tests were used to perform the statistical analysis.

RESULTS

COL1A1 -1997G > T (p=0.04) and TGFB1 Leu10Pro (p=0.02) were found to be associated with adjusted lumbar spine (LS) BMD. Interactions were observed between: the COL1A1 -1997 G/T and Sp1 polymorphisms (p < 0.01 for LS BMD) and the COL1A1 -1663 indelT and VDR ApaI polymorphisms (p < 0.01 for femoral neck (FN) BMD). The COL1A1 GDs and ESR1 LPX haplotypes were associated with FN BMD (p=0.03 and p=0.03).

CONCLUSIONS

Polymorphisms at COL1A1 and TGFB1 and haplotypes at COL1A1 and ESR1 were found to be associated with BMD in a cohort of postmenopausal Spanish women. Moreover, COL1A1 polymorphisms showed significant interactions among them and with the VDR 3' polymorphisms.

Molecular genetic studies of gene identification for osteoporosis: a 2004 update

This review summarizes comprehensively the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of December 2004. It is intended to constitute a sequential update of our previously published review covering the available data up to the end of 2002. Evidence from candidate gene association studies and genome-wide linkage studies in humans, as well as quantitative trait locus mapping animal models are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. An important extension of this update is incorporation of functional genomic studies (including DNA microarrays and proteomics) on osteogenesis and osteoporosis, in light of the rapid advances and the promising prospects of the field. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.

Gene polymorphisms involved in the regulation of bone quality

Osteoporotic fractures in subjects at advanced age constitute a tremendous and growing problem. Established lifestyle risk factors can explain only a modest proportion of the liability to osteoporotic fractures. Bone mineral density (BMD) is considered the best established risk factor for osteoporotic fractures. The importance of genetic factors in the quality of bone is substantial, but no consensus exists yet on the genes that are involved. However, concomitant diseases, balance disorders and lifestyle habits are more important for fractures in elderly subjects. The abundance of common sequence variations, so-called polymorphisms, in the human genome and their high frequency in the population have made them targets to explain variation in the risk. Some genes have been identified that appear to be involved in the regulation of bone mass and in the pathogenesis of osteoporosis. Among these are those coding for the two estrogen receptors (ERalpha and ERbeta), the androgen receptor (AR) and the vitamin D receptor (VDR). In addition, enzymes involved in the biogenesis of estrone and estradiol have attracted attention as well as polymorphisms in the regulatory region of the type I collagen gene, COLIA1, affecting the binding site for the transcription factor Specificity protein 1 (Sp1). Although evidence suggests that the quality of bone is determined to a large extent by genetic factors, research so far has not been able to unequivocally identify genes involved in this matter. Over the last years a large number of studies have pointed to the variability in many genes and their relation with BMD, bone-related symptoms or specific therapies. The findings emphasize the complexity of the genetics of bone mass and bone loss.