RESULTS: ATG16L1, IBD5, and IL23R SNPs were significantly associated with CD. Multivariate analysis showed independent CD association for carriers of ATG16L1 (odds ratio [OR] = 1.8, 95% confidence interval [CI] 1.09-3.24), IBD5-IGR2230 (OR = 2.16, 95% CI 1.30-3.59), and IL23R-rs10889677 (OR = 2.13, 95% CI 1.39-3.28) while retaining association for NOD2 mutation carriers (OR = 4.45, 95% CI 2.68-7.38), IBD family history (OR = 2.75, 95% CI 1.42-5.31), tobacco (OR = 2.06, 95% CI 1.35-3.14), and Jewish ethnicity (OR = 20.1, 95% CI 2.16-186.8). IL23R minor variants for Arg381Gln and Intron 6 rs7517848 showed independent, CD protection and 3' untranslated variant rs108896778 showed risk. MDR analysis suggested an interaction between IBD5, ATG16L1, and IL23R risk alleles. Penetrance values for ATG16L1 and IBD5 were 0.27% for heterozygotes, and 0.35% and 0.44%, respectively, for homozygotes. IL23R rs108896778 penetrance was 0.37%