S1PR1 and Crohn disease: No differential expression was observed for other SMAD7-related genes, namely, SMAD2, SMAD3, and SMAD4. Under-regulation of SMAD7 and S1PR1 was also observed in another autoimmune disease, Crohn’s disease (CD) (−4.6-fold, -1.6-fold, respectively), suggesting the presence of common markers for autoimmune diseases.