Abstract

Objective: We performed a comprehensive genetic association study of common variation spanning the IGF2BP2 locus, in order to replicate the association of the ‘confirmed’ type 2 diabetes susceptibility variants rs4402960 and rs1470579 in the French Caucasian population, and to further characterise the susceptibility variants at this novel locus.

Research Design and Methods: We genotyped a total of 21 tagging SNPs spanning the IGF2BP2 locus in our type 2 diabetes case-control cohort comprising in 3,093 French Caucasian subjects.

Results: IGF2BP2 variants rs4402960 and rs1470579 were not associated with type 2 diabetes in the present study (P = 0.632 and P = 0.896, respectively). Meta-analysis of genotype data from over 34,000 subjects demonstrated that our inability to replicate rs4402960/rs1470579 was consistent with the findings from several previous GWAS datasets that were under-powered to detect this modest association signal (OR 1.14). We obtained novel evidence that rs9826022, a borderline rare variant (5% MAF) in the 3′ downstream region, was associated with type 2 diabetes (P = 0.0002; OR 1.53 [95% CI 1.22-1.91]). This result was corroborated by the meta-analysis of 10,542 genotypes from the current study and GWAS datasets using both fixed (P = 9.47 × 10⁻⁶; OR 1.30 [95% CI 1.16-1.46]) and random effects (P = 0.001; 1.30 [95 %CI 1.11-1.52)] calculations.

Conclusions: We were unable to replicate the confirmed rs4402960/rs1470579 susceptibility variants, but found novel evidence for a rare variant in the 3′ downstream region of IGF2BP2. Further genetic and functional studies are required to identify the aetiological IGF2BP2 variants.