HapMap genotypes were obtained from the 1000 Genomes June 2011 phase I low-pass whole-genome SNP genotype release and transformed to UCSC Genome Browser (hg18) coordinates. Missing values were imputed by BIMBAM (v.1.0) using the default parameters to derive mean imputed genotypes. SNVs with MAF < 0.05 and SNVs with significant deviation from Hardy-Weinberg equilibrium (Fischer’s exact test, p < 0.001) were excluded, reducing the set to 9,345,571 SNPs and indels for association analyses.