Genetic factors are known to be associated with IBD and 240 risk variants for IBD have been reported by Genome-Wide Association studies (GWASs) to date, which include genes related with the intestinal epithelial barrier [e.g., nucleotide-binding oligomerization domain 2 (NOD2)] and genes encoding pro-inflammatory cytokines [e.g., tumor necrosis factor-α (TNF-α)] [6,7]. This evidence concerns the gene TNF and inflammatory bowel disease.