Second, failure to detect a prominent association signal in the present study cannot provide conclusive exclusion of any given gene. This is the consequence of several factors including: less-than-complete coverage of common variation genome-wide on the Affymetrix chip; poor coverage (by design) of rare variants, including many structural variants (thereby reducing power to detect rare, penetrant, alleles)25; difficulties with defining the full genomic extent of the gene of interest; and, despite the sample size, relatively low power to detect, at levels of significance appropriate for genome-wide analysis, variants with modest effect sizes (odds ratio (OR) < 1.2).
