Recently, Limon et al. have reported that Malassezia restricta, the common skin resident fungus, is linked to the pathogenesis of CD, especially in patients harboring the IBD-linked polymorphism in CARD9 (S12N), and that the colonization of M. restricta exacerbates disease severity in DSS-induced colitis in murine models [134]. This evidence concerns the gene CARD9 and irritable bowel syndrome.