Genotyping was performed at the Genome Technology Access Center at Washington University School of Medicine in St. Louis (http://gtac.wustl.edu/) using the Illumina Human OmniExpress array 12.VI (Illumina, San Diego, CA, USA). We also included in the analysis genotypes for subjects (n=275) from these 118 families who were genotyped in a previous case-control GWAS using the Illumina 1M array10. For quality control purposes, 51 of the 275 subjects were genotyped again on the Illumina Human OmniExpress array. Imputed data were obtained using the program BEAGLE25. A detailed description of imputation and subsequent data cleaning is included in supplementary information.
