rs4607103

This association study examined 43 diabetes-related SNPs in relation to diastolic dysfunction and cardiovascular disease across two Swedish cohorts. HNF1B rs757210 (T-allele) was the main finding, associated with prevalent diastolic dysfunction in both the discovery cohort (MPP-RES; OR 1.21, P=0.024) and replication cohort (VARA; OR 1.38, P=0.042), and with increased risk of incident CVD (HR 1.05, P=0.042) but not CHF over 30+ years of follow-up.

Of 40 SNPs previously associated with type 2 diabetes, 19 (48%) introduce or remove CpG sites. In 84 human pancreatic islet donors, all 16 analyzed CpG-SNPs showed statistically significant differential DNA methylation (p≤2.3×10⁻⁵). Several CpG-SNPs including rs391300 (SRR), rs5945326 (DUSP9), rs11708067 (ADCY5), rs5015480 (HHEX), rs13266634 (SLC30A8), rs1801214 (WFS1), rs564398 (CDKN2A), and rs2237895 (KCNQ1) were associated with differential gene expression, alternative splicing, or hormone secretion, suggesting DNA methylation-mediated mechanisms linking genetic variants to type 2 diabetes pathogenesis.

Population-based study of 6,733 non-diabetic Finnish men examining associations between 19 confirmed type 2 diabetes risk loci and tissue-specific insulin resistance indices. Type 2 diabetes risk SNPs in KCNJ11 (rs5219) and HHEX (rs1111875) showed significant associations with lower liver insulin resistance (p<0.0013 and p=5.4×10⁻⁵, respectively), while the Pro12 allele of PPARG2 (rs1801282) was significantly associated with higher adipocyte insulin resistance (p=6.2×10⁻⁵).

This association study of 4,213 Danish individuals examined 25 type 2 diabetes risk variants and their association with birthweight. The study found that type 2 diabetes risk alleles near ADCY5 (rs11708067, β = -33 g, p = 0.004), CDKAL1 (rs7756992, β = -22 g, p = 0.04), and HHEX-IDE (rs1111875, β = -16 g in meta-analysis, p = 8×10⁻⁵, n = 25,164) were associated with reduced birthweight, supporting the fetal insulin hypothesis. Meta-analyses confirmed these associations and showed no strong general effect on birthweight from the 25 common type 2 diabetes risk alleles combined.

This paper applies a bias correction method for odds ratio estimates from GWAS discovery data, demonstrating that the 'winner's curse' affects initial effect size estimates. The authors applied conditional maximum likelihood estimation to correct bias in GWAS findings from multiple complex diseases (breast cancer, colorectal cancer, lung cancer, prostate cancer, type I and II diabetes) and show that bias-adjusted odds ratios are substantially more consistent with subsequent replication studies, with selection-adjusted confidence intervals providing better uncertainty quantification than uncorrected estimates.

Replication study of 7 meta-analysis-derived type 2 diabetes susceptibility SNPs in 6,244 Japanese individuals across 3 independent populations. Only rs864745 in JAZF1 showed nominal association (OR 1.148, 95% CI 1.034-1.275, p=0.0098) but not after Bonferroni correction; other loci did not reach statistical significance, suggesting these European-identified variants have minor or absent effects in Japanese populations.

This study tests the thrifty genotype hypothesis by examining 17 confirmed type 2 diabetes susceptibility loci and 13 obesity-susceptibility loci for signatures of positive selection. Using ancestral/derived allele analysis, integrated haplotype scores (iHS), and population differentiation (FST), the authors found limited evidence supporting the thrifty genotype hypothesis. Only rs7901695 at TCF7L2 showed notably elevated FST values (0.579 between JPT+CHB and YRI populations), and FTO showed the strongest selection signal among obesity loci (iHS=1.991).

This prospective study of 16,143 individuals from the Malmö Preventive Project (mean follow-up 23 years) investigated whether genetic variants in 26 genes previously associated with type 2 diabetes or metabolic syndrome components could predict future development of metabolic syndrome. Polymorphisms in TCF7L2 (rs7903146, OR 1.10, p=0.00097), FTO (rs9939609, OR 1.08, p=0.0065), WFS1 (rs10010131, OR 1.07, p=0.0078), and IGF2BP2 (rs4402960, OR 1.07, p=0.021) predicted metabolic syndrome development, with TCF7L2, WFS1, and IGF2BP2 acting through hyperglycemia and FTO through obesity. A composite genotype score of 17 polymorphisms predicted metabolic syndrome risk (OR 1.04, p<0.00001), with carriers of ≥19 risk alleles having 51% increased risk compared to carriers of ≤12 alleles.