rs4506565

This case-control study examined 200 T2DM patients and 200 healthy controls from North India to assess association of TCF7L2 gene polymorphisms with type 2 diabetes risk. The TT genotype of rs4506565 was significantly more frequent in diabetic patients (49%) vs controls (32.5%, OR=1.99, p=0.0008), and the CC genotype of rs11196205 was more frequent in patients (51%) vs controls (30%, OR=0.41, p=0.001). The haplotype T-C was also significantly associated with T2DM (p=0.000384).

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.

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.

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 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.

This comprehensive review article traces the evolution of pharmacogenetics from single-gene analysis to whole-genome approaches. It discusses validated pharmacogenetic biomarkers with clinical impact including CYP2D6, CYP2C9, CYP2C19, TPMT, DPD, VKORC1, UGT1A1, and ADRB1/ADRB2, providing examples of how genetic variants affect drug metabolism and response. The paper emphasizes the importance of integrating pharmacogenetic information into clinical practice and drug development.

This study replicates the strong association between TCF7L2 variants and type 2 diabetes in an Indian population of 955 patients and 399 controls. All three SNPs (rs7903146, rs12255372, rs4506565) showed significant association with diabetes (ORs 1.46-1.50, p<1×10^-4), with rs12255372 showing the strongest homozygous effect (OR 2.28). The risk allele at rs12255372 was also associated with higher fasting and 2-hour plasma glucose and increased insulin resistance in non-diabetic subjects.