Flagellin is capable of inducing antibody responses through TLR5 (Lopez-Yglesias et al., 2014), and an increased abundance of flagellin-producing species belonging to Clostridium cluster XIVa has been reported in IBS subjects (Salonen et al., 2010; Jeffery et al., 2012a). The gene discussed is TLR5; the disease is irritable bowel syndrome.