The cystic fibrosis F508del mutation in Crohn's disease

We read with much interest the recent study by Bahmanyar et al. [1], where they tested the hypothesis that heterozygous carriage of cystic fibrosis transmembrane conductance regulator (CFTR) mutations may have a protective effect on the risk of gastrointestinal (GI) diseases of the epithelial barrier, which include inflammatory bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC). From the analysis of a very large number of obligate carriers [parents and siblings of cystic fibrosis (CF) patients] and non-carriers, and the observation that GI diseases occur with similar frequencies in these two groups, the authors conclude by ruling out the existence of such protective effect.