Implication of genetic variants near SLC30A8, HHEX, CDKAL1, CDKN2A/B, IGF2BP2, FTO, TCF2, KCNQ1, and WFS1 in Type 2 Diabetes in a Chinese population

Background: Recently, several genome-wide and candidate gene association studies have identified many novel genetic loci for type 2 diabetes (T2D); among these genes, CDKAL1, IGF2BP2, SLC30A8, CDKN2A/B, HHEX, FTO, TCF2, KCNQ1, and WFS1 are the most important. We aimed to determine the effects of these genetic loci associated with T2D in the Chinese Han population of China. Methods: Single-nucleotide polymorphisms (SNPs) in or near CDKAL1, IGF2BP2, SLC30A8, CDKN2A/B, HHEX, FTO, TCF2, KCNQ1, and WFS1 genes were genotyped in a case-control Chinese Han sample living in Beijing, China involving 1024 patients with T2D and 1005 control subjects. Results: 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. Not only did an association between WFS1-rs6446482 and early-onset T2D exist in the subgroup analysis, but TCF2-rs7501939 and WFS1-rs6446482 were also confirmed to confer risk for T2D in this meta-analysis. Moreover, the relationship between FTO-rs8050136 and body mass index, together with the effect of CDKAL1-rs10946398 on beta cell function, was also observed in the control individuals. Conclusions: Our findings support the important contribution of these genetic loci to susceptibility for T2D in the Chinese Han population in Beijing of China.