Intestinal biopsies obtained during ileocolonoscopy from 52 IBD patients (21 with Crohn's disease, 29 with ulcerative colitis and 2 with unclassified IBD, Supplementary Table 2) and 19 controls were analysed for FNDC4 and FNDC5 expression using quantitative reverse transcription–PCR (RT–qPCR). This evidence concerns the gene FNDC4 and Crohn disease.