In Crohn′s disease, one of the main inflammatory bowel diseases in humans traditionally associated with a Th1 cytokine profile, the TGF-β1 pathway is compromised due to the high expression of Mothers against decapentaplegic homolog (Smad)7, which negatively regulates TGF-β1-associated Smad signaling through various mechanisms (e.g., inhibition of Smad 2/3 phosphorylation, inactivation/degradation of TGF-β1 receptors) [26]. This evidence concerns the gene TGFB1 and Crohn disease.