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- Grundberg, Elin, 1979-
(författare)
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Genetic Variability in Human Bone Phenotypes : The Vitamin D Receptor Gene and the Estrogen Receptor-α Cofactor RIZ Gene
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Important candidate genes to human bone phenotypes are those involved in the regulation of hormonal action, such as the vitamin D receptor (VDR) and the estrogen receptor-α (ERα) genes and their cofactors. RIZ1 is a specific ERα cofactor proved to strongly enhance the function of the ERα. The main focus of this thesis has been to study genetic variants in the VDR and RIZ genes and their associations to human bone phenotypes using candidate gene and functional approaches. Specifically, polymorphisms in the VDR 3’ untranslated region (UTR) and a deletion/insertion polymorphism of a proline in the RIZ gene were investigated.The candidate gene approach was applied to large-scale population-based cohorts of pre-and post-menopausal women from Sweden and of elderly men from Sweden and Hong Kong. VDR 3’ UTR polymorphisms were associated with peak bone mass and body composition in young women. Further analysis of common VDR 3’ UTR haplotypes confirmed the association with BMD and risk of fractures in elderly men from Sweden and Hong Kong. The VDR polymorphisms were investigated for cis-acting effects, affecting allelic expression in the normal chromosomal context of human bone cells. The VDR allelic transcripts in the bone samples were unequally expressed, suggesting presence of regulatory variants in the 3’ UTR. The polymorphism in the RIZ gene was strongly associated to BMD in pre- and postmenopausal women and in elderly men. The functional analyses included reporter constructs containing the RIZ polymorphic variants transfected in a cell line and its abilities in coactivating the ERα were examined. The variants were functionally different in coactivating the ERα-receptor complex. To summarize, the results of this thesis show novel evidence for functional relevant polymorphisms in candidate genes to human bone phenotypes. These polymorphisms may contribute to the variation seen in BMD and risk of fractures in the population.
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| 3. |
- Pettersson-Kymmer, Ulrika, et al.
(författare)
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Genome-wide association study meta-analysis identifies the SOAT1/AXDND1 locus to be associated with hip and forearm fracture risk
- 2013
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Ingår i: Bone Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Hip and forearm fractures are the two clinically most important non-vertebral fractures. Twin studies have demonstrated a high heritability of these fractures and the heritable component of fracture risk is largely independent of BMD. To identify common genetic variants associated with hip and forearm fractures, we performed a genome-wide association study (GWAS ~ 2.5 million SNPs) meta-analysis of two large fracture data sets within the well-characterized UFO cohort (UFO-hip; 1014 hip fractures and 862 controls, and UFO-forearm; 1060 forearm fractures and 1055 controls). All fractures were confirmed through radiographic reports. Replication was performed in the Women’s Health Initiative (WHI) cohort (1845 hip fractures verified by medical records and 2120 controls). We identified one SNP within the SOAT1/AXDND1 locus (1q25.2) that was associated with fracture risk at genome wide significance (OR per allele=1.33; P=3.1×10−8) in the UFO discovery meta-analysis. This SNP was associated with fracture risk both in the WHI replication cohort (OR 1.16, P=2.1×10−3) and in the combined analyses comprising 7956 subjects (3919 cases and 4037 controls; OR=1.24, P=5.6×10−10). However, it was not associated with BMD or biochemical bone markers, suggesting that its association with fractures is BMD-independent. A genetic score (GS), including information from 63 SNPs earlier shown to be reproducibly associated with BMD, was significantly associated with both hip (P=7.9×10−4) and forearm (P=8.6×10−5) fractures. Models including both the SNP in the SOAT1/AXDND1 locus and the GS demonstrated that the impact of the SNP in the SOAT1/AXDND1 locus on fracture risk was independent of the BMD-associated GS. In summary, both a BMD-associated GS and a non-BMD associated genetic variant in the SOAT1/AXDND1 locus are associated with hip and forearm fractures.
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