The increased susceptibility to colitis observed in conventional Card9−/− mice, as evidenced by higher weight loss and greater histopathologic alterations [8, 14], was observed in Card9−/− mice whatever the microbiota (WT ➔ GF Card9−/− and Card9−/− ➔ GF Card9−/−; Fig. 2B − D, Supp. The gene discussed is CARD9; the disease is colitis.