In addition to the meta-analytic association testing per SNP, we also evaluated the significance of all genes across the genome. We followed the procedure proposed by Liu et al. and incorporated in the program VEGAS65, which is suitable for meta-analysis results because it does not require raw genotype data but instead uses the p-values of SNPs as input. Gene-based p-values were obtained by using a maximum of 107 simulations to correctly account for the linkage disequilibrium (LD) structure among SNPs within a gene. We included SNPs located up to 20kb down- or upstream of a gene. A gene was considered genome-wide significant if a P < 2.5 × 10−6 (0.05 / 20 000) was obtained.
