Treatment with AA147 ameliorated DSS-induced colitis in Pcdh20 CKO mice, characterized by less weight loss (Fig. 6a), lower DAI (Fig. 6b), longer colon length (Fig. 6c, d), lower levels of pathological scores (Fig. 6e), and lower MPO activity in colonic tissue (Fig. 6f) than those in PBS-treated Pcdh20 CKO mice with colitis. The gene discussed is MPO; the disease is colitis.