Grasberger et al. (2021)) showed that the deleterious DUOX2 variant is associated with elevated plasma levels of interleukin 17C and an increase in specific Aspergillus phylum pathogens, which are associated with an increased risk of inflammatory bowel disease. Recent studies have shown that elevated DUOX2 contributes to intestinal epithelial barrier dysfunction, microbiome alterations, and subclinical inflammation in IBD, while inhibition of its activation significantly improves disease outcomes (Hazime et al., 2025). Here, IL17C is linked to inflammatory bowel disease.