The article by Yang et al 1 contributes to the emerging evidence that genetic predisposition to Crohn's Disease (CD) has an ethnicity-specific variation.s1–s4 The genetic architecture of autoimmune and inflammatory diseases has been subject to recent positive selection in human history, probably driven by the historical exposure to pathogens.2 s5–s7 Thus, the differing genetic susceptibilities in East Asians (Koreans and Japanese) vis-a-vis the Caucasoid Euro-Americans might reflect the differences in their historical exposure to predominant pathogens occurring during the historical migrations of anatomically modern humans (AMH) while they populated the globe.s8 Gene(s) or gene pathways involved in innate immune control of intracellular bacteria (eg, NOD2, ATG16L1, IRGM) and in the IL-23/Th17 pathway are predominant susceptibility loci for Crohn's in Caucasoid, but characteristically not so in East Asians.s1, s4 Interestingly, these gene(s) or gene pathways play a primary role in the immune response to human mycobacterial infections, …