We combined the findings identified by candidate gene association studies and GWAS into a list of 849 SNPs in 843 haplotypes. Since many of the genetic susceptibility SNPs may provide genetic 'tag markers', while these tag SNPs were generally designed to detect linkage disequilibrium blocks and functional SNPs may be easily left out in most GWAS platforms [32], we thus used the whole-genome linkage disequilibrium data identified by HapMap [33] to expand the list into 1,907 SNPs by adding SNPs that displayed strong linkage disequilibrium with these genetic marker SNPs in all three HapMap populations.
