rs2191349

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.

Transethnic fine-mapping study of glycaemic traits in 26,760 participants (Hispanic/Latino, African, Asian, and Native American) using the Metabochip. Replicated 31/39 fasting glucose and 14/17 fasting insulin loci from European GWAS. Identified two novel secondary signals at G6PC2-rs477224 and GCK-rs2908290, a population-specific signal at G6PC2-rs77719485 in African ancestry, and one novel locus at SLC17A2-rs75862513 for fasting insulin.

Family-based study examining parent-of-origin effects (POE) on type 2 diabetes risk in 4,211 individuals from Botnia and 1,463 from the Hungarian Transdanubian Biobank. Three loci showed nominal POE, with the strongest signal at rs7578597 in THADA showing excess maternal transmission of the risk T allele to diabetic offspring (Botnia pPOE=0.01, HTB pPOE=0.045, combined pPOE=0.0006). Five CpG sites flanking rs7578597 showed differential methylation between diabetic and non-diabetic islets, supporting potential THADA imprinting. Meta-analysis confirmed association with type 2 diabetes (OR=1.24, 95% CI 1.12-1.36, p=1.96×10⁻⁵).

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.

Transethnic genome-wide meta-analysis in 159,940 individuals identified 60 common genetic variants associated with HbA1c levels. Variants were classified as glycemic (19), erythrocytic (22), or unclassified (19) based on their biological mechanisms. Glycemic variants were associated with higher type 2 diabetes risk (OR=1.05 per allele, p=3×10⁻²⁹), while erythrocytic variants were not. The X-linked G6PD G202A variant showed a large effect in African Americans (0.81% HbA1c reduction per allele) but minimal effects in other ancestries, potentially causing 2% of African American T2D cases to remain undiagnosed when using HbA1c screening.

This case-control study investigated 25 T2DM-associated SNPs in a multi-ethnic Hawaiian cohort (291 GDM cases, 734 controls) and found ethnicity-specific associations with gestational diabetes. Key findings in Filipinos included rs1113132 (EXT2, OR=1.52, p=0.028), rs1111875 (HHEX, OR=1.5, p=0.047), rs2237892 (KCNQ1, OR=0.49, p<0.001), rs10830963 (MTNR1B, OR=0.63, p=0.025), and rs13266634 (SLC30A8, OR=0.58, p=0.011). In Japanese women, rs4402960 (IGFBP2, OR=0.5, p=0.031) and rs2237892 (KCNQ1, OR=0.5, p=0.03) were significant. Pacific Islanders showed associations with rs10830963 (MTNR1B, OR=0.52, p=0.037) and rs13266634 (SLC30A8, OR=2.43, p=0.03). No SNPs showed consistent associations across all three ethnic groups.

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.