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Variants at the Znf365 locus are associated with femoral neck bone mineral density in men
Abstracts / Bone 47 (2010) S72–S241
fractures were tested using the chi-square test. The differences of quantitative variables between the genotypes were analysed by covariance analysis (GLM procedure) after correction of the measurements for age, BMI and daily calcium intake. A relative risk (RR) was calculated by published methods. The genotype frequencies were 14.4%, 46.9%, and 38.7% for BB, Bb, and bb, respectively. We found a significant effect of VDR/Bsm I polymorphism on NFR and SFR (P < 0.05), a higher risk was evaluated for bb genotype. It indicates a high proportion of the Bsm I polymorphism effect on the vertebral fracture risk. The RR for bb genotype carriers was 1.25 and 1.34 for NFR and SFR (insignificant), respectively. Homozygotes bb also disposed the increased OC and CTX (P < 0.05) indicating increased bone remodeling activity. On the other hand, BMD was associated insignificantly, although the differences between the homozygous genotypes were close to the statistical significance (P = 0.076). The results suggested that the higher risk of fractures in bb individuals could be associated with the higher bone turnover in these women. Results of genetic analysis in Slovak population could contribute to a more comprehensive view of role of genetics in osteoporosis development. Ultimately, the results could be practically applied in the prediction of osteoporosis and fracture risk. All procedures were approved by the Ethical Committee of the Specialized Hospital of St. Svorad in Nitra (Slovakia). The study was supported by the grant KEGA 3/7008/09. Disclosure of Interest: None declared Keywords: fracture risk, Slovak population, VDR gene doi:10.1016/j.bone.2010.04.361
PP226 Variants at the Znf365 locus are associated with femoral neck bone mineral density in men R. McConnell⁎, S.H. Ralston on behalf of The FAMOS Consortium, O.M. Albagha Rheumatology, University of Edinburgh, Edinburgh, United Kingdom Osteoporosis is a common disease characterised by reduced bone mineral density (BMD) and increased risk of fracture. Genetic factors are important in osteoporosis but the majority of genes responsible remain to be identified. A previous genome wide linkage study identified a region on chromosome 10q21 that was linked to femoral neck (FN) in men under the age of 50 years (LOD score = 4.42) (Ralston et al 2005, Hum Mol Gen). The aim of this study was to fine map this region and identify the genetic variants contributing to FN-BMD regulation in men. We used family based association testing (FBAT) approach in families previously linked to 10q21 from the FAMOS population. 1900 tag single nucleotide polymorphism (SNP) were selected to capture most of the known genetic variations in linked region spanning 12 cM on chromosome 10q21. Genotyping was performed using illumina Goldengate platform. Quality control measures were applied to the genotype data to remove SNPs and individuals with low call rate, low genotype quality score and Mendelian errors, leaving a total of 66 families with genotype data for 1738 SNPs. Analysis using FBAT identified various hits with P < 0.001 located within ZNF365, ANK3, CTNNA3, and RHOBTB1. The most significant signal was for three SNPs (rs7074979, rs10740084 and rs10995212) located in the ZNF365 gene with P values of 2 × 10- 4, 3.5 × 10- 4 and 8 × 10- 4 respectively. Analysis of haplotypes formed by rs7074979 and rs10740084 showed stronger association with FN BMD with P = 9.2 × 10- 5. The identified polymorphisms are located within non-coding region of the gene and appear to have no functional significance based on bioinformatics analysis. We are currently screening the coding region of the ZNF365 for novel polymorphisms using DNA sequencing. ZNF365 has 4 isoforms, one of which is
S157
predominantly expressed in the nervous system and has no obvious function in bone but the other alternative splice variants may have an as yet unidentified role in bone metabolism. ZNF365 has a highly conserved homolog in mice (zfp365), to investigate its possible role in osteoclast development, macrophages from the bone marrow of CD1 mice were stimulated with MCSF and RANKL to form osteoclasts and the expression level of ZNF365 is currently being investigated during osteoclast formation. In conclusion we have identified variants in the ZNF365 to be associated with femoral neck BMD in young men but further studies will be required to confirm this finding. Disclosure of Interest: None declared Keywords: FBATS, osteoporosis, ZNF365 doi:10.1016/j.bone.2010.04.362
PP227 Genetic variants of FDPS and osteoporosis J.A. Riancho1,⁎, M.T. Zarrabeitia2, C. Valero1, J.M. Olmos1, J.L. Hernandez1, J. Arozamena1, V. Mijares1, J. Gonzalez-Macias1 1 Department of Medicine, University of Cantabria-Hospital U M Valdecilla-IFIMAV, Santander, Spain 2 Legal Medicine, University of Cantabria, Santander Farnesyl diphosphate synthase (FDPS) is a critical enzyme in the mevalonate pathway and is considered as a major target for aminobisphosphonates. FDPS inhibition results in a marked decrease in osteoclastic bone resoption. Therefore we hypothesized that polymorphisms of the FDPS gene could influence osteoclast activity and consequently bone mineral density (BMD). The study group included 1164 postmenopausal women who had BMD measured by DXA at the lumbar spine and the hip. They included normal volunteers and untreated patients with primary osteoporosis. They did not have other diseases or therapies known to affect bone mass. DNA was isolated from the peripheral blood and four single nucleotide polymorphisms of the FDPS gene were analyzed by using Taqman assays: rs17367421, rs11264359, rs17456 and rs2297480. In a preliminary analysis, the minor allele frequency of the non-synonymous rs17456 polymorphism was less than 0.5% in our population and therefore it was excluded. We did not find a significant association between the allles at the rs17367421 and rs2297480 loci and BMD. A small difference in hip BMD was found across the rs11264359 genotypes: AA 0.814 ± 0.134, AG 0.8271 ± 0.135, and GG 0842 ± 0.125 g/cm2 (nominal p-value for trend 0.043, not significant after multiple test correction). No significant genotype-related differences existed regarding lumbar spine BMD (p > 0.1). In conclusion, we found a marginally significant association of some common allelic variants of the FDPS gene with BMD. The results should be confirmed in other populations, but they do not suggest an important influence of these genetic variants on bone mass. Disclosure of Interest: None declared Keywords: bone mineral density, farnesyl diphosphate synthase, polymorphisms doi:10.1016/j.bone.2010.04.363
PP228 Haplotypes of the central region of the type I estrogen recptor gene are associated with hip fractures J.A. Riancho1,⁎, J. Velasco1, J.L. Hernandez1, J.L. Perez-Castrillon2, M.T. Zarrabeitia3, M.A. Alonso4, J. Gonzalez-Macias1
fractures were tested using the chi-square test. The differences of quantitative variables between the genotypes were analysed by covariance analysis (GLM procedure) after correction of the measurements for age, BMI and daily calcium intake. A relative risk (RR) was calculated by published methods. The genotype frequencies were 14.4%, 46.9%, and 38.7% for BB, Bb, and bb, respectively. We found a significant effect of VDR/Bsm I polymorphism on NFR and SFR (P < 0.05), a higher risk was evaluated for bb genotype. It indicates a high proportion of the Bsm I polymorphism effect on the vertebral fracture risk. The RR for bb genotype carriers was 1.25 and 1.34 for NFR and SFR (insignificant), respectively. Homozygotes bb also disposed the increased OC and CTX (P < 0.05) indicating increased bone remodeling activity. On the other hand, BMD was associated insignificantly, although the differences between the homozygous genotypes were close to the statistical significance (P = 0.076). The results suggested that the higher risk of fractures in bb individuals could be associated with the higher bone turnover in these women. Results of genetic analysis in Slovak population could contribute to a more comprehensive view of role of genetics in osteoporosis development. Ultimately, the results could be practically applied in the prediction of osteoporosis and fracture risk. All procedures were approved by the Ethical Committee of the Specialized Hospital of St. Svorad in Nitra (Slovakia). The study was supported by the grant KEGA 3/7008/09. Disclosure of Interest: None declared Keywords: fracture risk, Slovak population, VDR gene doi:10.1016/j.bone.2010.04.361
PP226 Variants at the Znf365 locus are associated with femoral neck bone mineral density in men R. McConnell⁎, S.H. Ralston on behalf of The FAMOS Consortium, O.M. Albagha Rheumatology, University of Edinburgh, Edinburgh, United Kingdom Osteoporosis is a common disease characterised by reduced bone mineral density (BMD) and increased risk of fracture. Genetic factors are important in osteoporosis but the majority of genes responsible remain to be identified. A previous genome wide linkage study identified a region on chromosome 10q21 that was linked to femoral neck (FN) in men under the age of 50 years (LOD score = 4.42) (Ralston et al 2005, Hum Mol Gen). The aim of this study was to fine map this region and identify the genetic variants contributing to FN-BMD regulation in men. We used family based association testing (FBAT) approach in families previously linked to 10q21 from the FAMOS population. 1900 tag single nucleotide polymorphism (SNP) were selected to capture most of the known genetic variations in linked region spanning 12 cM on chromosome 10q21. Genotyping was performed using illumina Goldengate platform. Quality control measures were applied to the genotype data to remove SNPs and individuals with low call rate, low genotype quality score and Mendelian errors, leaving a total of 66 families with genotype data for 1738 SNPs. Analysis using FBAT identified various hits with P < 0.001 located within ZNF365, ANK3, CTNNA3, and RHOBTB1. The most significant signal was for three SNPs (rs7074979, rs10740084 and rs10995212) located in the ZNF365 gene with P values of 2 × 10- 4, 3.5 × 10- 4 and 8 × 10- 4 respectively. Analysis of haplotypes formed by rs7074979 and rs10740084 showed stronger association with FN BMD with P = 9.2 × 10- 5. The identified polymorphisms are located within non-coding region of the gene and appear to have no functional significance based on bioinformatics analysis. We are currently screening the coding region of the ZNF365 for novel polymorphisms using DNA sequencing. ZNF365 has 4 isoforms, one of which is
S157
predominantly expressed in the nervous system and has no obvious function in bone but the other alternative splice variants may have an as yet unidentified role in bone metabolism. ZNF365 has a highly conserved homolog in mice (zfp365), to investigate its possible role in osteoclast development, macrophages from the bone marrow of CD1 mice were stimulated with MCSF and RANKL to form osteoclasts and the expression level of ZNF365 is currently being investigated during osteoclast formation. In conclusion we have identified variants in the ZNF365 to be associated with femoral neck BMD in young men but further studies will be required to confirm this finding. Disclosure of Interest: None declared Keywords: FBATS, osteoporosis, ZNF365 doi:10.1016/j.bone.2010.04.362
PP227 Genetic variants of FDPS and osteoporosis J.A. Riancho1,⁎, M.T. Zarrabeitia2, C. Valero1, J.M. Olmos1, J.L. Hernandez1, J. Arozamena1, V. Mijares1, J. Gonzalez-Macias1 1 Department of Medicine, University of Cantabria-Hospital U M Valdecilla-IFIMAV, Santander, Spain 2 Legal Medicine, University of Cantabria, Santander Farnesyl diphosphate synthase (FDPS) is a critical enzyme in the mevalonate pathway and is considered as a major target for aminobisphosphonates. FDPS inhibition results in a marked decrease in osteoclastic bone resoption. Therefore we hypothesized that polymorphisms of the FDPS gene could influence osteoclast activity and consequently bone mineral density (BMD). The study group included 1164 postmenopausal women who had BMD measured by DXA at the lumbar spine and the hip. They included normal volunteers and untreated patients with primary osteoporosis. They did not have other diseases or therapies known to affect bone mass. DNA was isolated from the peripheral blood and four single nucleotide polymorphisms of the FDPS gene were analyzed by using Taqman assays: rs17367421, rs11264359, rs17456 and rs2297480. In a preliminary analysis, the minor allele frequency of the non-synonymous rs17456 polymorphism was less than 0.5% in our population and therefore it was excluded. We did not find a significant association between the allles at the rs17367421 and rs2297480 loci and BMD. A small difference in hip BMD was found across the rs11264359 genotypes: AA 0.814 ± 0.134, AG 0.8271 ± 0.135, and GG 0842 ± 0.125 g/cm2 (nominal p-value for trend 0.043, not significant after multiple test correction). No significant genotype-related differences existed regarding lumbar spine BMD (p > 0.1). In conclusion, we found a marginally significant association of some common allelic variants of the FDPS gene with BMD. The results should be confirmed in other populations, but they do not suggest an important influence of these genetic variants on bone mass. Disclosure of Interest: None declared Keywords: bone mineral density, farnesyl diphosphate synthase, polymorphisms doi:10.1016/j.bone.2010.04.363
PP228 Haplotypes of the central region of the type I estrogen recptor gene are associated with hip fractures J.A. Riancho1,⁎, J. Velasco1, J.L. Hernandez1, J.L. Perez-Castrillon2, M.T. Zarrabeitia3, M.A. Alonso4, J. Gonzalez-Macias1