The impact of Crohn's disease genes on healthy human gut microbiota: A pilot study

We read with interest the paper by Rehman et al 1 reporting the contribution of Nod2 genotype to the composition of gut microbiota in mice and Crohn's disease (CD) patients. This was followed by a similar description for another CD-predisposing gene, FUT2.2 To date, 163 CD- and ulcerative colitis-risk loci have been identified, and while most of the known causative genes are involved in immune functions and response to infections, their effects on the composition of the gut microbiota are mostly unknown. Studies like those mentioned above are therefore very important, since the relative abundance of specific enteric bacteria has been clearly shown to be of pathogenetic relevance in mouse models of colitis.3 By studying genotype–microbiota correlations in healthy individuals, key information could also be sought for devoid of potentially confounding effects from disease status and therapeutic treatment.