ATG16L1 and Crohn disease: However, there were no differences in the prevalence of the minor allele for the three genetic polymorphisms of NOD2 associated with Crohn's disease (SNPs: rs2066844, rs2066845, rs2066847) as previously reported.[17] There was also no difference in the frequency of RAC1 or ATG16L1 polymorphism between the two groups.