Moreover, an association with both asthma and Crohn’s disease was found for gene loci DENND1B, SMAD3 and SLC22A4/5 (5q31/IBD5), while the ORMDL3 gene variants present in Crohn’s disease and ulcerative colitis were also associated with childhood-onset asthma [27,33]. Here, SMAD3 is linked to Crohn disease.