Given that several alleles associated with higher FG levels were also associated with increased T2D risk and that the T2D genes TCF7L2 and SLC30A8 showed association with FG, we systematically investigated association of all established T2D loci with the same four fasting diabetes-related quantitative traits. We found directionally consistent nominal associations (P<0.05) of T2D risk alleles with higher FG for 11 of 18 established T2D loci, including MTNR1B (Supplementary Table 3). These data demonstrate that a large T2D effect size does not always translate to an equivalently large FG effect in non-diabetic persons, as clearly highlighted when contrasting the remarkably small effects of TCF7L2 on FG compared to MTNR1B (Table 2).
