rs7903146

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.

A literature review of 70 studies examining single nucleotide polymorphisms (SNPs) associated with obesity in Mexican populations published 2011-2021. The authors identified SNPs with differential behavior in Mexican compared to Caucasian populations, including rs17782313 (MC4R), rs6548238 (TMEM18), rs6265 (BDNF), rs7498665 (SH2B1), and notably rs6232 (PCSK1) associated with early-onset obesity in Mexican youth. The review emphasizes ethnicity-dependent genetic effects on BMI heritability (40-70%) and highlights genes involved in cholesterol metabolism and adipokine signaling pathways.

This genome-wide interaction analysis in 6,224 African Americans identified CMIP rs17197883 as a novel type 2 diabetes susceptibility locus through interaction with the insulin secretion variant MTNR1B rs10830963. The CMIP variant showed antagonistic interaction (P_INTXN = 1.43×10^-8) with opposite effects depending on MTNR1B carrier status: OR = 2.29 (95% CI 1.59-3.28) in AIRg-lowering allele carriers vs. OR = 0.78 (95% CI 0.67-0.90) in non-carriers.

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.

This comprehensive review synthesizes literature on gestational diabetes mellitus (GDM), demonstrating its complex multifactorial etiology involving genetic factors (SNPs in GCKR, KCNQ1, MTNR1B, TCF7L2), epigenetic modifications (DNA methylation and microRNA expression), and alterations in microbial composition across multiple body sites. While certain SNP variants are associated with GDM phenotypes globally, genetic predisposition alone does not explain disease development; lifestyle factors can modify epigenetic signatures and microbiota composition to modulate risk. Evidence indicates genes, epigenetic alterations, and microbiota can transfer from mother to offspring with long-term health consequences.

A case-control study of 674 GDM patients and 690 controls combined with a meta-analysis found that the G allele of rs10830963 and T allele of rs1387153 in MTNR1B are significantly associated with increased risk of gestational diabetes mellitus (GDM). Meta-analysis of 6 studies showed rs10830963 G allele increased GDM risk in co-dominant model (OR 1.62, 95% CI 1.34-1.94) and rs1387153 T allele increased risk in co-dominant model (OR 1.53, 95% CI 1.26-1.86).

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).

This retrospective pharmacogenomic analysis of 961 type 2 diabetes patients from four 24-week phase III trials examined whether TCF7L2 gene variants influence response to linagliptin (DPP-4 inhibitor). Linagliptin lowered HbA1c across all rs7903146 genotypes (CC: -0.82%, CT: -0.77%, TT: -0.57%), with significantly reduced response in homozygous risk carriers (TT vs CC: difference ~0.26%, p=0.0182), indicating that diabetes susceptibility genes contribute to inter-individual treatment response variability.

In vitro enhancer screen of the 92 kb TCF7L2 type 2 diabetes GWAS interval identified 9 of 28 sequences (30%) with cis-regulatory activity in multiple cell lines. The risk T allele of rs7903146 showed significantly stronger enhancer activity than the protective C allele in myoblasts and a strong trend in neuronal cells, supporting cis-regulatory variation as a mechanism for diabetes susceptibility.

This systematic study screened 18 T2D-associated SNPs and 5 environmental factors (trans-β-carotene, cis-β-carotene, γ-tocopherol, heptachlor epoxide, PCB170) for gene-environment interactions using NHANES data (1999-2000, 2001-2002). The strongest interaction was between rs13266634 (SLC30A8) and trans-β-carotene: in subjects with low trans-β-carotene levels, the per-risk-allele OR was 1.8 (95% CI 1.3-2.6), 40% higher than the marginal effect, and this interaction withstood Bonferroni correction (p = 0.006, FDR 1.5%). Four interactions total achieved FDR < 20%, suggesting that nutrient levels modify genetic risk for T2D.

Case-control study of 673 preterm birth (PTB) cases vs 1,119 controls across four maternal cohorts testing 35 SNPs in cardiovascular, inflammatory, and metabolic disease genes. Found 13 statistically significant associations with PTB (P<0.05), more than expected by chance (binomial P=0.02). Most significant was HLA-DQA1 rs9272346 G allele protective effect in US White mothers (P=0.02, OR=0.65, 95% CI 0.46-0.94), which nominally replicated in Danish cohort (P=0.02, OR=0.85, 95% CI 0.75-0.97) but lost significance after correction for multiple testing.

A case-control study of 443 T2D cases and 532 controls from a Russian population (HAPIEE cohort) investigating four polymorphisms as predictors of type 2 diabetes development over 10 years. rs7903146 in TCF7L2 was significantly associated with T2D risk (TT genotype RR 3.90, 95% CI 2.31-6.61; TC genotype RR 1.86, 95% CI 1.42-2.43; CC protective RR 0.37, 95% CI 0.29-0.49, all p<0.001). No significant associations were found for rs1799883 (FABP2), rs2237892 (KCNQ1), or rs6773957 (ADIPOQ). TCF7L2 rs7903146 retained significance in risk models for both men and women.

This prospective cohort study demonstrates that parental history of type 2 diabetes and the TCF7L2 rs7903146 at-risk variant (T allele) are independently associated with incident hypertension over 9 years in the DESIR cohort (n=2,391; OR for TCF7L2 at-risk variant = 1.48, p=0.006), with stronger effect in individuals with elevated HbA1c (OR 1.82, p=0.004). Additionally, in the RISC cohort (n=1,047), reduced insulin secretion at baseline was inversely associated with 3-year incident hypertension (OR 0.75 per SD, p=0.007), independent of insulin resistance.

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.

Association analysis of 31 GWAS-confirmed type 2 diabetes SNPs in 3,089 Indian sib pairs (2,528 for quantitative traits, 561 for diabetes) identified significant associations with intermediate traits: CDKAL1 rs7756992, TCF7L2 rs7903146 and rs12255372 with fasting glucose (β=0.009-0.01, p≤0.01); ADAM30 rs2641348, NOTCH2 rs10923931, TCF-2/HNF1B rs757210, and CDKN2A/B rs10811661 with fasting insulin and HOMA-IR (β=±0.05-0.09, p≤0.05); and THADA rs7578597 with type 2 diabetes (OR 1.5, p=0.03).

This case-control study analyzed 7 SNPs in 6 genes previously associated with type 2 diabetes (T2DM) in 235 kidney transplant patients medicated with tacrolimus to determine their effect on new-onset diabetes after transplantation (NODAT). While no individual SNP showed significant association with NODAT, patients carrying >7 of the 14 'diabetogenic' alleles had significantly higher NODAT risk (OR 2.17, 95% CI 1.18–3.99, p=0.015), particularly for late-onset NODAT (OR 1.37 per allele, 95% CI 1.05–1.78, p=0.017).

Meta-analysis of TCF7L2 rs7903146 C-to-T polymorphism across six European populations (999 LADA patients, 5,358 controls) demonstrates significant association with latent autoimmune diabetes in adults (LADA), with T allele conferring OR 1.28 (p<0.0001). The effect size is comparable to type 2 diabetes, but not type 1 diabetes. Gene effect is modulated by BMI: susceptibility in non-overweight individuals is 2.84-fold higher than in overweight LADA patients.

This functional study examined how the TCF7L2 rs7903146 T allele, the strongest genetic risk factor for type 2 diabetes, impacts islet morphology and function in non-diabetic individuals. Using pancreatic tissue from 187 brain-deceased donors, the T/T homozygous genotype was associated with reduced basal and glucose-stimulated insulin secretion (~30% reduction), increased islet size, reduced islet density (~30% fewer islets), and altered alpha/beta cell ratios (alpha cells increased ~30%, beta cells decreased ~20%), suggesting the variant impairs beta cell function and alters islet organization.

This association study identified rs10811661 near CDKN2A/B on chromosome 9p21, a type 2 diabetes risk SNP, as significantly associated with diabetic nephropathy in 2,963 type 1 diabetes patients (OR 1.33, p=0.00045). The association was replicated in meta-analysis across four cohorts (n>5,000; OR 1.15, p=0.011) and was particularly strong for end-stage renal disease (OR 1.35, p=0.00038). The SNP was also associated with severe retinopathy but not cardiovascular disease.

A case-control study of 837 schizophrenic patients and 1,109 controls in a Han Chinese population found no significant association between the SLC30A8 rs13266634 (R325W, C/T) polymorphism and schizophrenia risk (χ² = 1.95, p = 0.38 for genotype; χ² = 0.47, p = 0.50 for allele frequencies), nor with any schizophrenia clinical symptoms. This null finding suggests that despite rs13266634 being a robust type 2 diabetes risk variant across multiple GWAS, it does not contribute to the genetic basis of the schizophrenia-T2DM comorbidity.

This multi-stage genome-wide association study in 11,705 BRCA1 mutation carriers identified three novel cancer risk-modifying loci: rs2290854 at 1q32 associated with breast cancer (HR=1.14), and rs17631303 (HR=1.27) and rs4691139 (HR=1.20) at 17q21.31 and 4q32.3 respectively associated with ovarian cancer. The 4q32.3 locus showed BRCA1-specific associations. These findings enable improved absolute risk estimation for BRCA1 carriers, with estimated breast cancer lifetime risks ranging from 28-50% for the lowest-risk 5% to 81-100% for the highest-risk 5%.

This prospective cohort study of 24,799 Swedish participants examined gene-diet interactions between the TCF7L2 rs7903146 risk variant and dietary fiber intake on type 2 diabetes. The T allele increased diabetes risk (OR 1.44, p=4.6×10⁻¹⁹), but this risk escalated with higher fiber intake (from OR 1.24 to OR 1.56 across fiber quintiles, p=0.049). Protective effects of high fiber were restricted to CC genotype carriers, while T allele carriers showed no protection.

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.

Genome-wide association study (GWAS) of type 2 diabetes in 837 Mexican-Americans cases and 436 controls from Starr County, Texas, combined with meta-analysis of 967 cases and 343 controls from Mexico City. The study identified 49 high-quality SNPs in 14 genomic regions associated with type 2 diabetes, including novel loci in PER3, PARD3B, EPHA4, TOMM7, PTPRD, and IL34. Top signals showed odds ratios ranging from 1.26 to 1.83. Functional annotation revealed significant enrichment of expression quantitative trait loci (eQTL) in muscle and adipose tissues among top associated variants.

This case-control study examined TCF7L2 polymorphisms (rs12255372 and rs7903146) in 240 youth with type 2 diabetes and 999 controls (86 NHW cases, 154 African-American cases). Among African-American youth, each copy of the T allele at rs7903146 was associated with 1.97-fold increased odds for type 2 diabetes (p=0.0002), with stronger effects than previously reported in adults. No significant association was observed in non-Hispanic white youth (OR 1.09, p=0.70), suggesting different genetic contributions to early-onset type 2 diabetes by race/ethnicity.

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 functional study examined how carriers of the TCF7L2 rs7903146 TT genotype (risk allele for type 2 diabetes) differ metabolically from CC genotype carriers (31 matched pairs, mean age 53-54 years). Following a meal challenge, TT carriers showed elevated incremental AUC for plasma glucose (97.9 vs 21.8 mmol/l×min, p=0.001), increased proinsulin AUC (6,917 vs 6,033 pmol/l×min, p=0.03), elevated GIP AUC (14,590 vs 12,310 pmol/l×min, p=0.004), and higher C-peptide AUC (417.1 vs 397.6 nmol/l×min, p=0.04). These findings suggest dysregulated glucose metabolism and elevated incretin secretion in normoglycemic risk allele carriers.

This association study analyzed four T2D-related SNPs (rs5219, rs1801282, rs7903146, rs12255372) in 26 Yakut patients with type 2 diabetes via pyrosequencing. No statistically significant differences were found between Yakut T2D cases and control groups for KCNJ11, PPARG, or TCF7L2 polymorphisms. The study identified strong linkage disequilibrium between TCF7L2 rs7903146 and rs12255372 (D'=1, LOD=4.92) in Yakuts and demonstrated that the risk T-allele frequency of TCF7L2 SNPs is notably lower in Asian populations (3.8% in Yakuts, 2-3% in Japanese and Chinese) compared to European and African populations.

Meta-analysis of four prospective UK cohort studies (>17,000 individuals) examining ADRA2A genetic variants and metabolic traits. rs553668 G>A was associated with increased type 2 diabetes risk (OR 1.17, 95% CI 1.04-1.31, p=0.01) and higher fasting glucose (0.03 mmol/l per allele, p=0.016). Secondary ADRA2A SNPs showed associations with blood pressure, BMI, and glucose-related phenotypes. Haplotype analysis identified a rare rs553668A/rs10885122T haplotype strongly associated with elevated fasting glucose.

A comprehensive review of nutrigenetics and nutrigenomics examining how genetic variants influence individual responses to nutrients and dietary interventions. The paper discusses associations between numerous SNPs (rs9939609 in FTO, rs2287019 in GIPR, rs7903146 in TCF7L2, rs5219 in KCNJ11, and many others) and metabolic traits including obesity, type 2 diabetes, and other chronic diseases, along with epigenetic mechanisms by which phytochemicals (curcumin, resveratrol, lycopene) modulate gene expression. The review synthesizes current evidence for precision nutrition approaches tailored to individual genetic profiles.

This population-based longitudinal study investigated the association between TCF7L2 rs7903146 polymorphism and incident impaired fasting glucose (IFG) in 6,529 ARIC Study participants (1,377 African American and 5,152 Caucasian) followed for 9 years. In Caucasians, the rs7903146 T allele was significantly associated with IFG risk (HR CT vs. CC = 1.09, 95% CI 1.03-1.15; HR TT vs. CC = 1.18, 95% CI 1.05-1.33), with stronger effects in obese individuals (HR TT = 1.65, 95% CI 1.25-2.17) and those with high triglycerides (HR TT = 1.72, 95% CI 1.21-2.43). No association was observed in African Americans, highlighting population-specific genetic effects.

This GWAS of fasting glucose in the ARIC study examined 5,782-8,372 individuals across four longitudinal visits and identified five genomic regions significantly associated with fasting glucose (p < 5×10⁻⁸): GCKR, G6PC2, GCK, SLC30A8, and MTNR1B. The study demonstrated that averaging fasting glucose measures across visits improved statistical power and detected additional signals (GCKR rs780094, SLC30A8 rs13266634) not visible in single-visit analyses. Analysis of candidate SNPs revealed significant interactions with diabetes status: associations with fasting glucose were stronger in non-diabetic individuals than in those with prevalent diabetes for multiple SNPs including rs10830963 (MTNR1B), rs560887 (G6PC2), rs4607517 (GCK), and rs780094 (GCKR).

This prospective family-based cohort study examined TCF7L2 genetic variants in 1,094 Han Chinese subjects and found pleiotropic effects on diabetes progression. Variants in the exon 4 LD block (rs7903146, rs7079711, rs4506565, rs7895340) were associated with impaired insulin secretion and increased diabetes risk (hazard ratio = 2.61, p = 0.009), while 3' end variants (rs290481, rs290487) were associated with insulin resistance markers but not diabetes progression. TCF7L2 expression was inversely correlated with insulin resistance in human adipose tissue.

The HERITAGE Family Study examined eight type 2 diabetes susceptibility variants in 481 sedentary individuals undergoing 20-week endurance training. PPARG rs1801282 (Pro12Ala) was the only significant finding: Ala carriers showed greater improvements in glucose tolerance (p=0.0008), glucose effectiveness (p=0.004), and disposition index (p=0.003) in response to exercise training, though no associations were found with other recently identified GWAS variants.

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.

A type 2 diabetes susceptibility variant in TCF7L2 (rs7903146, T allele) confers substantial risk for diabetes in cystic fibrosis patients. The T allele was associated with diabetes in cystic fibrosis (HR 1.75 per allele, 95% CI 1.3-2.4, p=0.0006 in family-based study; OR 1.6-1.9 in case-control replication) and decreased age at diagnosis by 7 years. This genetic risk factor is shared between type 2 diabetes and cystic fibrosis-related diabetes, with especially strong effects (HR 2.9, p=0.00011) in CF patients not treated with glucocorticoids.

Nested case-control study of 258 prostate cancer cases and 258 matched controls in the CLUE II prospective cohort examining genetic variants in inflammation and obesity-related genes. The IL10 -1082G>A variant (rs1800896, A allele) was positively associated with prostate cancer risk (AG vs GG: OR=1.69, 95% CI 1.10-2.60; AA vs GG: OR=1.81, 95% CI 1.11-2.96), while a TLR4 variant (rs4986790) showed inverse association, and no consistent associations were found for obesity-related gene variants.

This case-control study in 869 Korean women with gestational diabetes mellitus (GDM) and 632 non-diabetic controls examined whether type 2 diabetes-associated genetic variants discovered in recent GWAS are also associated with GDM. Multiple variants showed significant associations with GDM, including rs7756992 and rs7754840 in CDKAL1 (OR 1.55, p=4.17×10⁻⁹), rs10811661 in CDKN2A-CDKN2B (OR 1.49, p=1.05×10⁻⁷), variants in HHEX, rs4402960 in IGF2BP2 (OR 1.18, p=0.03), rs13266634 in SLC30A8 (OR 1.24, p=0.005), and rs7903146 in TCF7L2 (OR 1.58, p=0.038).

In 1,412 non-diabetic German participants, carriers of higher cumulative loads of type 2 diabetes risk alleles (rs7903146 in TCF7L2, rs7754840 in CDKAL1, rs7923837 in HHEX, rs13266634 in SLC30A8) showed significantly accelerated age-dependent decline in insulin secretion and impaired proinsulin conversion. Individuals with 5-8 risk alleles exhibited a ~13-18% reduction in insulin secretion compared to carriers of ≤3 alleles, with effects particularly pronounced in obese participants.

This study examined TCF7L2 variants in 2,512 Framingham Heart Study participants and confirmed that rs7903146 T risk allele associates with increased fasting plasma glucose (p=0.01) and a 23.5% higher proinsulin/insulin ratio (p=1×10⁻⁷) compared to C/C homozygotes, supporting the hypothesis of impaired beta cell insulin processing. However, the authors found no association between TCF7L2 haplotype A and obesity measures (BMI p=0.98), suggesting previous positive associations were likely due to ascertainment bias.

This study characterized TCF7L2 splicing patterns in five human tissues, showing tissue-specific differences with high exon 4 and 15 incorporation in pancreatic islets. While no significant splicing differences were observed between rs7903146 genotype groups, exon 4 incorporation in islets significantly correlated with plasma HbA1c levels (r=0.758, p=0.018), suggesting a link between TCF7L2 splicing and glucose homeostasis.

This study of 81 young healthy Danish men examined the physiological mechanisms of type 2 diabetes risk conferred by rs7903146 in TCF7L2. Carriers of the T allele showed reduced 24-hour plasma insulin concentrations (p<0.05), impaired insulinotropic response to GLP-1 (p=0.03) and GIP (p=0.07) during hyperglycaemic clamps, and significantly elevated hepatic glucose production (EGP) despite reduced plasma glucagon levels. Beta cell responsiveness to glucose during meal tests was also reduced in T allele carriers (β-index: p<0.003).

This association study of 1,578 German non-diabetic individuals at increased type 2 diabetes risk found that the WFS1 rs10010131 variant was associated with reduced oral glucose tolerance test (OGTT)-derived insulin secretion (p=0.03). Importantly, glucose stimulation via intravenous injection did not reduce insulin secretion in carriers, indicating the variant specifically impairs glucagon-like peptide-1 (GLP-1)-induced insulin secretion (first phase p=0.007, second phase p=0.04). The genetic effect was independent of insulin sensitivity and the TCF7L2 locus.

This case-control and family-based association study tested whether 18 type 2 diabetes susceptibility loci are associated with type 1 diabetes in 7,606 type 1 diabetic cases and 8,218 controls. Only PPARG (rs1801282/Pro12Ala, OR=0.91, p=0.004) and HHEX-IDE (rs1111875, OR=0.94, p=0.003) showed evidence of association with type 1 diabetes. The authors conclude that type 1 and type 2 diabetes do not share a common genetic background, supporting the view that type 1 diabetes is primarily an autoimmune disease.

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.

This study examined whether genetic markers (HLA-DQB1, PTPN22, INS VNTR, TCF7L2) could distinguish autoimmune from non-autoimmune diabetes in 1,642 young (15-34 years) and 1,619 middle-aged (40-59 years) Swedish diabetic patients. TCF7L2 rs7903146 CT/TT genotypes were significantly more common in young GADA-negative than GADA-positive patients (53% vs 43%; p=0.0004), suggesting TCF7L2 variants help differentiate type 2 diabetes from autoimmune diabetes in young but not middle-aged patients.

This study examined whether TCF7L2 SNPs (rs7903146, rs12255372, rs7901695, rs11196205, rs7895340) are associated with cardiovascular disease (CVD) and mortality in the ARIC cohort of 13,369 participants. The T-allele of rs7903146 was not significantly associated with incident coronary heart disease, ischemic stroke, CVD, or all-cause mortality in the full cohort or when stratified by race. A weak association with incident CHD was observed in whites with prevalent diabetes (HR = 1.21, p = 0.04) but not in blacks, suggesting TCF7L2's increased health risk is specific to diabetes rather than general cardiovascular disease.

This replication study tested newly identified type 2 diabetes susceptibility loci in a Norwegian population-based cohort of 1,638 type 2 diabetes patients and 1,858 controls. The authors confirmed associations for rs10811661 near CDKN2B (OR 1.20, p=0.004), rs9939609 in FTO (OR 1.14, p=0.006), and rs13266634 in SLC30A8 (OR 1.20, p=3.9×10⁻⁴). They found borderline association for rs4402960 in IGFBP2 (OR 1.10, p=0.074) but no support for SNPs near FLJ39370 and PKN2.

This candidate gene study of 1,065 German participants investigated seven type 2 diabetes-associated SNPs and their relationship with proinsulin processing. Risk alleles in TCF7L2 (rs7903146), CDKAL1 (rs7754840), and SLC30A8 (rs13266634) significantly impaired proinsulin to insulin conversion (p<0.05), while variants in HHEX showed impaired insulin secretion without affecting proinsulin conversion, demonstrating that these two aspects of beta cell dysfunction are independently regulated.

The D.E.S.I.R. prospective cohort study (N=4,707) validated 22 SNPs from genome-wide association studies for type 2 diabetes effects on glucose homeostasis. Risk alleles in SLC30A8 (rs13266634, P=0.0003), NGN3 (rs10823406, P=0.01), and MMP26 (rs2499953, P=0.04) were associated with elevated fasting glucose, while CDKAL1 variants (rs7756992, P=0.003) showed reduced fasting insulin. However, associations with type 2 diabetes incidence were modest (HRs ranging 1.25-2.03), and only SLC30A8 remained significant after Bonferroni correction for HOMA-B.