IBD disease activity in clinical practice is often assessed in a composite manner by (i) evaluation of symptoms using validated indices such as the Crohn’s disease activity index (CDAI) or the Harvey-Bradshaw index (HBI) for CD, and the simple clinical colitis activity index for UC; (ii) assessment of biomarkers such as C-reactive protein (CRP) or faecal calprotectin (FC) and (iii) endoscopic evaluation[3]. This evidence concerns the gene CRP and Crohn disease.