R. gnavus were associated with advanced coronary artery diseases (CAD) (Toya et al., 2020), inflammatory bowel disease (Hall et al., 2017), and obesity (Petriz et al., 2014), which could secrete a complex polysaccharide that potently induces inflammatory cytokine (TNF-α) secretion by dendritic cells (Henke et al., 2019). The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.