Recently, several groups have carried out whole-genome association studies in European and European-origin populations and found novel type 2 diabetes-susceptibility genes, fat mass and obesity associated (FTO), solute carrier family 30 (zinc transporter), member 8 (SLC30A8), haematopoietically expressed homeobox (HHEX), exostoses (multiple) 2 (EXT2), CDK5 regulatory subunit associated protein 1-like 1 (CDKAL1), cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) (CDKN2B) and insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), which had not been in the list of functional candidates.
We identify T2D-associated variants in an intergenic region of chromosome 11p12, contribute to the identification of T2D-associated variants near the genes IGF2BP2 and CDKAL1 and the region of CDKN2A and CDKN2B, and confirm that variants near TCF7L2, SLC30A8, HHEX, FTO, PPARG, and KCNJ11 are associated with T2D risk.
Four of the nine SNPs revealed a significant association with T2D; PPARG2 (Pro12Ala) [odds ratio (OR) 0.12; 95% confidence interval (CI) (0.03-0.52); p = 0.005], IGF2BP2 [OR 1.37; 95% CI (1.04-1.82); p = 0.027], TCF7L2 [OR 1.64; 95% CI (1.20-2.24); p = 0.001] and FTO [OR 1.46; 95% CI (1.11-1.93); p = 0.007] after adjusting for age, sex and BMI.
Polymorphisms in susceptibility genes for type 2 diabetes (TCF7L2, WFS1, IGF2BP2) and obesity (FTO) predispose to the metabolic syndrome by increasing the risk of one specific component of the metabolic syndrome.
We observed significant association of SNPs in IGF2BP2 (1.17 [1.03-1.32]; P = 0.014) and SLC30A8 (1.12 [1.01-1.25]; P = 0.033) with combined IFG/type 2 diabetes.
A total of 15 SNPs were genotyped.Eight SNPs in five loci were found to be associated with type 2 diabetes: rs3802177 [odds ratio (OR) = 1.16 (95% confidence interval (CI) 1.05-1.27); P = 4.5 x 10(-3)] in SLC30A8; rs1111875 [OR = 1.27 (95% CI 1.14-1.40); P = 1.4 x 10(-5)] and rs7923837 [OR = 1.27 (95% CI 1.13-1.43); P = 1.0 x 10(-4)] in HHEX; rs10811661 [OR = 1.27 (95% CI 1.15-1.40); P = 1.9 x 10(-6)] in CDKN2B; rs4402960 [OR = 1.23 (95% CI 1.11-1.36); P = 8.1 x 10(-5)] and rs1470579 [OR = 1.18 (95% CI 1.07-1.31); P = 8.3 x 10(-4)] in IGF2BP2; and rs7754840 [OR = 1.28 (95% CI 1.17-1.41); P = 4.5 x 10(-7)] and rs7756992 [OR = 1.27 (95% CI 1.15-1.40); P = 9.8 x 10(-7)] in CDKAL1.
We conclude that rs11705701 in IGF2BP2 is associated with body fat and this effect on body fat influences insulin resistance which may contribute to T2DM risk.
In our case-control subjects, susceptibility to type 2 diabetes was replicated in TCF7L2 (rs12255372), CDKAL1 (rs7756992, rs7754840), HHEX (rs7923837), IGF2BP2 (rs4402960 and rs1470579), CDKN2A/B (rs10811661), and SLC30A8 (rs13266634).
In the total population, the TCF7L2 and IGF2BP2 variants most strongly associated with increased risk for type 2 diabetes/IGT and increased AUC for glucose, while the CDKAL1 polymorphism associated with decreased AUC for insulin.
This review provides a background to the IMP protein family with an emphasis on human IMP2, followed by a closer look at the GWA studies to evaluate the significance, if any, of the proposed correlation between IMP2 and T2D.
In Chinese Han, we replicated the associations between 7 genetic loci and T2D, with risk allele-specific odds ratios (ORs) as follows: 1.27 (95% CI, 1.11-1.45; p = 0.0008) for CDKAL1-rs10946398, 1.26 (95% CI, 1.08-1.47; p = 0.003) for IGF2BP2-rs4402960, 1.19 (95% CI, 1.04-1.37; p = 0.009) for SLC30A8-rs13266634, 1.22 (95% CI, 1.06-1.41; p = 0.005) for CDKN2A/B-rs10811661, 1.20 (95% CI, 1.01-1.42; p = 0.03) for HHEX-rs5015480, 1.37 (95% CI, 1.19-1.69; p = 1.0 x 10(-4)) for KCNQ1-rs2237892, and 1.24 (95% CI, 1.01-1.52; p = 0.046) for FTO-rs8050136 after adjustment for age, gender, and body mass index.
Common variants in PPARG, KCNJ11, TCF7L2, SLC30A8, HHEX, CDKN2A, IGF2BP2, and CDKAL1 genes have been shown to be associated with type 2 diabetes in European populations by genome-wide association studies.
The analyses showed that age (P < 0.0001), BMI (P < 0.0001), and six variants (IGF2BP2rs4402960, P = 0.002; ADIPOQ+276 G>T, P = 0.004; UCP2Ala55Val, P = 0.01; CDKN2AI2B rs3731201, P = 0.02; rs495490, P = 0.02, and rsl 0811661, P = 0.03) were significantly associated with the risk of IFG/IGT/T2DM.
We analysed here the association between T2D (and related traits) and rs4402960 and rs1470579 in IGF2BP2, and rs46522 and rs6949019 (marking IGF2BP1 and IGF2BP3 respectively) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (N approximately 2500 aged 65-96 years).
The IGF2BP2rs1470579 and rs4402960 polymorphisms may be associated with the development of T2DM, and these polymorphisms may affect the therapeutic efficacy of repaglinide in Chinese T2DM patients.
Variants in genes HHEX, CDKN2A/2B, JAZF1, and IGF2BP2 were found to interact with prenatal nutrition in relation to T2D risk and glucose levels in later life.
The pooled results indicated that the rs4402960 polymorphism of the IGF2BP2 gene was related to increased risk of T2DM for T allele vs. G allele (OR = 1.13, 95% CI 1.11-1.15) under additive genetic model.
Association to type 2 diabetes was found for rs13266634 (SLC30A8), rs7923837 (HHEX), rs10811661 (CDKN2A/2B), rs4402960 (IGF2BP2), rs12779790 (CDC123/CAMK1D), and rs2237892 (KCNQ1).
In conclusion, this meta-analysis suggests that rs4402960 polymorphism in IGF2BP2 is associated with elevated T2D risk, but these associations vary in different ethnic populations.
To investigate this inconsistency, we performed a meta-analysis of 35 studies involving a total of 175,965 subjects for two wildly studied polymorphisms (rs4402960 and rs1470579) of the IFG2BP2 to evaluate the effect of IFG2BP2 on genetic susceptibility for T2D.
Seven SNPs in six genes known to increase the risk of T2DM in Caucasians were genotyped by means of TaqMan assays in 235 kidney transplant patients medicated with tacrolimus: rs4402960 and rs1470579 in IGF2BP2; rs1111875 in HHEX; rs10811661 upstream of CDKN2A/B; rs13266634 in SLC30A8; rs1801282 in PPARG; rs5215 in KCNJ11.
Common genetic risk variants at GCK, SLC30A8, IGF2BP2 and MTNR1B influence to different extents the development of IFG and the transition from IFG to type 2 diabetes.