| 1. |
- Andersen, Mette, et al.
(författare)
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Type 2 diabetes susceptibility gene variants predispose to adult-onset autoimmune diabetes
- 2014
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 57:9, s. 1859-1868
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Latent autoimmune diabetes in adults (LADA) is phenotypically a hybrid of type 1 and type 2 diabetes. Genetically LADA is poorly characterised but does share genetic predisposition with type 1 diabetes. We aimed to improve the genetic characterisation of LADA and hypothesised that type 2 diabetes-associated gene variants also predispose to LADA, and that the associations would be strongest in LADA patients with low levels of GAD autoantibodies (GADA). Methods We assessed 41 type 2 diabetes-associated gene variants in Finnish (phase I) and Swedish (phase II) patients with LADA (n=911) or type 1 diabetes (n=406), all diagnosed after the age of 35 years, as well as in non-diabetic control individuals 40 years or older (n=4,002). Results Variants in the ZMIZ1 (rs12571751, p=4.1 x 10(-5)) and TCF7L2 (rs7903146, p=5.8 x 10(-4)) loci were strongly associated with LADA. Variants in the KCNQ1 (rs2237895, p=0.0012), HHEX (rs1111875, p=0.0024 in Finns) and MTNR1B (rs10830963, p=0.0039) loci showed the strongest association in patients with low GADA, supporting the hypothesis that the disease in these patients is more like type 2 diabetes. In contrast, variants in the KLHDC5 (rs10842994, p=9.5 x 10(-4) in Finns), TP53INP1 (rs896854, p=0.005), CDKAL1 (rs7756992, p=7.0 x 10(-4); rs7754840, p=8.8 x 10(-4)) and PROX1 (rs340874, p=0.003) loci showed the strongest association in patients with high GADA. For type 1 diabetes, a strong association was seen for MTNR1B (rs10830963, p=3.2 x 10(-6)) and HNF1A (rs2650000, p=0.0012). Conclusions/interpretation LADA and adult-onset type 1 diabetes share genetic risk variants with type 2 diabetes, supporting the idea of a hybrid form of diabetes and distinguishing them from patients with classical young-onset type 1 diabetes.
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| 2. |
- Sandholm, Niina, et al.
(författare)
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Genome-wide association study of urinary albumin excretion rate in patients with type 1 diabetes
- 2014
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Ingår i: Diabetologia. - Berlin Heidelberg : Springer-Verlag. - 0012-186X .- 1432-0428. ; 57:6, s. 1143-1153
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: An abnormal urinary albumin excretion rate (AER) is often the first clinically detectable manifestation of diabetic nephropathy. Our aim was to estimate the heritability and to detect genetic variation associated with elevated AER in patients with type 1 diabetes.METHODS: The discovery phase genome-wide association study (GWAS) included 1,925 patients with type 1diabetes and with data on 24 h AER. AER was analysed as a continuous trait and the analysis was stratified by the use of antihypertensive medication. Signals with a p value <10(-4) were followed up in 3,750 additional patients withtype 1 diabetes from seven studies.RESULTS: The narrow-sense heritability, captured with our genotyping platform, was estimated to explain 27.3% of the total AER variability, and 37.6% after adjustment for covariates. In the discovery stage, five single nucleotide polymorphisms in the GLRA3 gene were strongly associated with albuminuria (p < 5 × 10(-8)). In the replication group, a nominally significant association (p = 0.035) was observed between albuminuria and rs1564939 in GLRA3, but this was in the opposite direction. Sequencing of the surrounding genetic region in 48 Finnish and 48 UK individuals supported the possibility that population-specific rare variants contribute to the synthetic associationobserved at the common variants in GLRA3. The strongest replication (p = 0.026) was obtained for rs2410601 between the PSD3 and SH2D4A genes. Pathway analysis highlighted natural killer cell mediated immunity processes.CONCLUSIONS/INTERPRETATION: This study suggests novel pathways and molecular mechanisms for the pathogenesis of albuminuria in type 1 diabetes.
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| 3. |
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| 4. |
- Bennet, Louise, et al.
(författare)
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Ethnic differences in the contribution of insulin action and secretion to type 2 diabetes in immigrants from the Middle East compared to native Swedes
- 2014
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Ingår i: Diabetes Research and Clinical Practice. - : Elsevier. - 0168-8227 .- 1872-8227. ; 105:1, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- Aims: We investigated insulin action (insulin sensitivity index, ISI) and insulin secretion (oral disposition indices, DIo) and studied metabolic, demographic and lifestyle-related risk factors for type 2 diabetes and insulin action, in the largest non-European immigrant group to Sweden, immigrants from Iraq and native Swedes.Methods: Population-based, cross-sectional study conducted 2010-2012 including residents 30-75 years of age born in Iraq or Sweden, in whom oral glucose tolerance tests were performed and sociodemography and lifestyle behaviors were characterized.Results: In Iraqis compared to Swedes, ISI was more impaired (76.9 vs. 102.3, p < .001) whereas corrected insulin response CIR was higher (226.6 vs. 188.6, p = .016). However, insulin secretion was inadequate given the substantial insulin resistance, as indicated by lower DIo indices in Iraqis than in Swedes (DIo 12,712.9 vs. 14,659.2, p < .001). The crude ethnic difference in ISI was not offset by traditional risk factors like waist circumference, body mass index or family history of diabetes. In Iraqis, ISI conveyed somewhat higher odds of type 2 diabetes than in Swedes (odds ratio OR 0.98, 95% CI 0.97-0.99) vs. OR 0.95, 0.92-0.99), as indicated by an interaction between country of birth and ISI (P-interaction = .044).Conclusion: This study reports ethnic differences in the contribution of insulin action to type 2 diabetes. Our data suggests that the impaired insulin action observed in immigrants from the Middle East to Sweden is not fully explained by established risk factors.(C) 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
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| 5. |
- Bennet, Louise, et al.
(författare)
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Ethnicity is an independent risk indicator when estimating diabetes risk with FINDRISC scores: A cross sectional study comparing immigrants from the Middle East and native Swedes
- 2014
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Ingår i: Primary Care Diabetes. - : Elsevier BV. - 1751-9918 .- 1878-0210. ; 8:3, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- Aims: This study sought to compare type 2 diabetes (T2D) risk indicators in Iraqi immigrants with those in ethnic Swedes living in southern Sweden. Methods: Population-based, cross-sectional cohort study of men and women, aged 30-75 years, born in Iraq or Sweden conducted in 2010-2012 in Malmö, Sweden. A 75 g oral glucose tolerance test was performed and sociodemographic and lifestyle data were collected. T2D risk was assessed by the Finnish Diabetes Risk Score (FINDRISC). Results: In Iraqi versus Swedish participants, T2D was twice as prevalent (11.6 vs. 5.8%, p < 0.001). A large proportion of the excess T2D risk was attributable to larger waist circumference and first-degree family history of diabetes. However, Iraqi ethnicity was a risk factor for T2D independently of other FINDRISC factors (odds ratio (OR) 2.5, 95% CI 1.6-3.9). The FINDRISC algorithm predicted that more Iraqis than Swedes (16.2 vs. 12.3%, p < 0.001) will develop T2D within the next decade. The total annual costs for excess T2D risk in Iraqis are estimated to exceed 2.3 million euros in 2005, not accounting for worse quality of life. Conclusions: Our study suggests that Middle Eastern ethnicity should be considered an independent risk indicator for diabetes. Accordingly, the implementation of culturally tailored prevention programs may be warranted. © 2014 Primary Care Diabetes Europe.
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| 6. |
- Claussnitzer, Melina, et al.
(författare)
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Leveraging cross-species transcription factor binding site patterns: from diabetes risk Loci to disease mechanisms.
- 2014
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 156:1-2, s. 343-358
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have revealed numerous risk loci associated with diverse diseases. However, identification of disease-causing variants within association loci remains a major challenge. Divergence in gene expression due to cis-regulatory variants in noncoding regions is central to disease susceptibility. We show that integrative computational analysis of phylogenetic conservation with a complexity assessment of co-occurring transcription factor binding sites (TFBS) can identify cis-regulatory variants and elucidate their mechanistic role in disease. Analysis of established type 2 diabetes risk loci revealed a striking clustering of distinct homeobox TFBS. We identified the PRRX1 homeobox factor as a repressor of PPARG2 expression in adipose cells and demonstrate its adverse effect on lipid metabolism and systemic insulin sensitivity, dependent on the rs4684847 risk allele that triggers PRRX1 binding. Thus, cross-species conservation analysis at the level of co-occurring TFBS provides a valuable contribution to the translation of genetic association signals to disease-related molecular mechanisms.
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| 7. |
- Fadista, Joao, et al.
(författare)
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Global genomic and transcriptomic analysis of human pancreatic islets reveals novel genes influencing glucose metabolism.
- 2014
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 111:38, s. 13924-13929
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variation can modulate gene expression, and thereby phenotypic variation and susceptibility to complex diseases such as type 2 diabetes (T2D). Here we harnessed the potential of DNA and RNA sequencing in human pancreatic islets from 89 deceased donors to identify genes of potential importance in the pathogenesis of T2D. We present a catalog of genetic variants regulating gene expression (eQTL) and exon use (sQTL), including many long noncoding RNAs, which are enriched in known T2D-associated loci. Of 35 eQTL genes, whose expression differed between normoglycemic and hyperglycemic individuals, siRNA of tetraspanin 33 (TSPAN33), 5'-nucleotidase, ecto (NT5E), transmembrane emp24 protein transport domain containing 6 (TMED6), and p21 protein activated kinase 7 (PAK7) in INS1 cells resulted in reduced glucose-stimulated insulin secretion. In addition, we provide a genome-wide catalog of allelic expression imbalance, which is also enriched in known T2D-associated loci. Notably, allelic imbalance in paternally expressed gene 3 (PEG3) was associated with its promoter methylation and T2D status. Finally, RNA editing events were less common in islets than previously suggested in other tissues. Taken together, this study provides new insights into the complexity of gene regulation in human pancreatic islets and better understanding of how genetic variation can influence glucose metabolism.
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| 8. |
- Flannick, Jason, et al.
(författare)
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Loss-of-function mutations in SLC30A8 protect against type 2 diabetes.
- 2014
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 46:4, s. 357-357
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Tidskriftsartikel (refereegranskat)abstract
- Loss-of-function mutations protective against human disease provide in vivo validation of therapeutic targets, but none have yet been described for type 2 diabetes (T2D). Through sequencing or genotyping of ∼150,000 individuals across 5 ancestry groups, we identified 12 rare protein-truncating variants in SLC30A8, which encodes an islet zinc transporter (ZnT8) and harbors a common variant (p.Trp325Arg) associated with T2D risk and glucose and proinsulin levels. Collectively, carriers of protein-truncating variants had 65% reduced T2D risk (P = 1.7 × 10(-6)), and non-diabetic Icelandic carriers of a frameshift variant (p.Lys34Serfs*50) demonstrated reduced glucose levels (-0.17 s.d., P = 4.6 × 10(-4)). The two most common protein-truncating variants (p.Arg138* and p.Lys34Serfs*50) individually associate with T2D protection and encode unstable ZnT8 proteins. Previous functional study of SLC30A8 suggested that reduced zinc transport increases T2D risk, and phenotypic heterogeneity was observed in mouse Slc30a8 knockouts. In contrast, loss-of-function mutations in humans provide strong evidence that SLC30A8 haploinsufficiency protects against T2D, suggesting ZnT8 inhibition as a therapeutic strategy in T2D prevention.
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| 9. |
- Giannini, Cosimo, et al.
(författare)
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Co-occurrence of Risk Alleles in or Near Genes Modulating Insulin Secretion Predisposes Obese Youth to Prediabetes
- 2014
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Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 37:2, s. 475-482
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVEParalleling the rise of pediatric obesity, the prevalence of impaired glucose tolerance (IGT) and type 2 diabetes (T2D) is increasing among youth. In this study, we asked whether the co-occurrence of risk alleles in or near five genes modulating insulin secretion (TCF7L2 rs7903146, IGF2BP2 rs4402960, CDKAL1 rs7754840, HHEX rs1111875, and HNF1A rs1169288) is associated with a higher risk of IGT/T2D in obese children and adolescents.RESEARCH DESIGN AND METHODSWe studied 714 obese subjects (290 boys and 424 girls; mean age 13.6 3.1 years; mean z score BMI 2.2 0.4) and evaluated the insulin secretion by using the oral minimal model and, in a subgroup of 37 subjects, the hyperglycemic clamp. Also, 203 subjects were followed up for a mean of 2.1 years.RESULTSWe observed that the increase of risk alleles was associated with a progressive worsening of insulin secretion (P < 0.001) mainly due to an impairment of the dynamic phase of insulin secretion (P = 0.004); the higher the number of the risk alleles, the higher the chance of progression from normal glucose tolerance (NGT) to IGT/T2D (P = 0.022). Also, for those who were IGT at baseline, a higher risk score was associated with a lower odds to revert to NGT (P = 0.026).CONCLUSIONSObese children and adolescents developing IGT/T2D have a higher genetic predisposition than those who do not show these diseases, and this predisposition is mainly related to gene variants modulating the early phase of insulin secretion. Although these data are very interesting, they need to be replicated in other cohorts.
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| 10. |
- Groop, Leif, et al.
(författare)
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Can genetics improve precision of therapy in diabetes?
- 2014
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Ingår i: Trends in Endocrinology and Metabolism. - : Elsevier BV. - 1879-3061 .- 1043-2760. ; 25:9, s. 440-443
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Tidskriftsartikel (refereegranskat)abstract
- Diabetes mellitus is a lifelong, incapacitating disease affecting multiple organs. Presently, type 2 diabetes (T2D) can neither be prevented nor cured and the disease is associated with devastating chronic complications. These complications impose an immense burden on the quality of life of patients and account for about 12% of direct health care costs in Europe. Genetic analysis will increase our understanding of this heterogeneous disease and may help offer more personalized treatment.
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