The importance of maintaining ROS in homeostasis is exemplified by the fact that IBD patients either have loss of function mutations or an upregulation of Duox2 (Haberman et al., 2014; MacFie et al., 2014; Hayes et al., 2015; Levine et al., 2016; Chu et al., 2017; Parlato et al., 2017). Here, DUOX2 is linked to inflammatory bowel disease.