information has become available in large GWAS samples. Given the availability of denser SNPs, which are expected to be in high linkage disequilibrium (LD) with the causal variants, we aim to extend the search for genetic variants (GVs) implicated in initiation to previously untagged common GVs, and to other (than common) GVs, such as low-frequency variants (1 % < MAF < 5 %). Such low frequency variants have not typically passed the quality control checks. However, the quality of imputation has been improved by recent advances in imputation techniques (Howie et al. 2012). This opens the door to including such GVs into a genome-wide association study.
