Distinct genetic loci, including mothers against decapentaplegic homolog 3 (SMAD3), DENN domain containing 1B (DENND1B), and Solute carrier family 22, member 4/5 [SLC22A4/5 (5q31/IBD5)], are known to be associated with both CD and asthma [30]. Here, DENND1B is linked to asthma.