| 1. |
- Florez, J. C., et al.
(författare)
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Association testing of common variants in the insulin receptor substrate-1 gene (IRS1) with type 2 diabetes
- 2007
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 50:6, s. 1209-1217
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Activation of the insulin receptor substrate-1 (IRS1) is a key initial step in the insulin signalling pathway. Despite several reports of association of the G972R polymorphism in its gene IRS1 with type 2 diabetes, we and others have not observed this association in well-powered samples. However, other nearby variants might account for the putative association signal. Subjects and methods We characterised the haplotype map of IRS1 and selected 20 markers designed to capture common variations in the region. We genotyped this comprehensive set of markers in several family-based and case-control samples of European descent totalling 12,129 subjects. Results In an initial sample of 2,235 North American and Polish case-control pairs, the minor allele of the rs934167 polymorphism showed nominal evidence of association with type 2 diabetes (odds ratio [OR] 1.25, 95% CI 1.03-1.51, p=0.03). This association showed a trend in the same direction in 7,659 Scandinavian samples (OR 1.16, 95% CI 0.96-1.39, p=0.059). The combined OR was 1.20 (p=0.008), but statistical correction for the number of variants examined yielded a p value of 0.086. We detected no differences across rs934167 genotypes in insulin-related quantitative traits. Conclusion/interpretation Our data do not support an association of common variants in IRS1 with type 2 diabetes in populations of European descent.
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| 2. |
- Ling, Charlotte, et al.
(författare)
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Impact of the peroxisome proliferator activated receptor-gamma coactivator-1 beta (PGC-1 beta) Ala203Pro polymorphism on in vivo metabolism, PGC-1 beta expression and fibre type composition in human skeletal muscle
- 2007
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 50:8, s. 1615-1620
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Peroxisome proliferator activated receptor-gamma coactivator-lp (PGC-1 beta, also known as PPARGCIB) expression is reduced in skeletal muscle from patients with type 2 diabetes mellitus and in elderly subjects. Ala203Pro, a common variant in the PGC-1 beta gene is associated with obesity. The aim of this study was to investigate whether the PGC-1 beta Ala203Pro polymorphism influences the age-related decline in skeletal muscle PGC-1 beta expression, in vivo metabolism and markers for muscle fibre type composition. Materials and methods The PGC-1 beta Ala203Pro polymerphism was genotyped in 110 young (age 28.0 +/- 1.9 years) and 86 elderly (age 62.4 +/- 2.0 years) twins and related to muscle PGC-1 beta expression, in vivo metabolism and markers for fibre type composition. Results Insulin-stimulated non-oxidative glucose metabolism (NOGM; p=0.025) and glycolytic flux rate (GF; p=0.026) were reduced in young Ala/Ala carriers compared with carriers of a 203Pro allele. In addition, a regression analysis, correcting for covariates, showed that the PGC-1 beta 203Pro allele was positively related to insulin-stimulated NOGM and GF in the young twins. While muscle expression of PGC-1 beta was reduced in elderly compared with young carriers of the Ala/Ala genotype (p <= 0.001), there was no significant age-related decline in PGC-1 beta expression in carriers of the 203Pro allele (p >= 0.4). However, a regression analysis, correcting for covariates, showed that only age was significantly related to muscle PGC-1 beta expression. Finally, PGC-1 beta expression correlated positively with markers for oxidative fibres in human muscle. Conclusions/interpretation This study suggests that young carriers of a PGC-1 beta 203Pro allele have enhanced insulin-stimulated glucose metabolism and may be protected against an age-related decline in PGC-1 beta expression in muscle.
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| 3. |
- Saxena, Richa, et al.
(författare)
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Genome-wide association analysis identifies loci for type 2 diabetes and triglyceride levels
- 2007
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 316:5829, s. 1331-1336
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Tidskriftsartikel (refereegranskat)abstract
- New strategies for prevention and treatment of type 2 diabetes (T2D) require improved insight into disease etiology. We analyzed 386,731 common single-nucleotide polymorphisms (SNPs) in 1464 patients with T2D and 1467 matched controls, each characterized for measures of glucose metabolism, lipids, obesity, and blood pressure. With collaborators (FUSION and WTCCC/UKT2D), we identified and confirmed three loci associated with T2D - in a noncoding region near CDKN2A and CDKN2B, in an intron of IGF2BP2, and an intron of CDKAL1 - and replicated associations near HHEX and in SLC30A8 found by a recent whole-genome association study. We identified and confirmed association of a SNP in an intron of glucokinase regulatory protein (GCKR) with serum triglycerides. The discovery of associated variants in unsuspected genes and outside coding regions illustrates the ability of genome-wide association studies to provide potentially important clues to the pathogenesis of common diseases.
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