Study materials
We used Affymetrix Genomewide SNP 5.0 genotyping data provided by the Korea Association Resource (KARE) consortium, Korean Genome Epidemiology Study (KoGES). As a control, we purchased a HapMap cell line, GM10851, from Coriell Institute for Medical Research (Camden, NJ, USA) and extracted genomic DNA using the DNeasy Blood & Tissue Kit (Qiagen, Hilden, Germany).