In IBD, whose major pathogenic processes involve the overreaction (hypersensitivity) of the immune response toward commensal intestinal bacteria, the mutation of the nucleotide-binding oligomerization domain 2 (NOD2) gene results in the reduction of antimicrobial peptides produced by Paneth cells (Larabi et al., 2020). The gene discussed is NOD2; the disease is irritable bowel syndrome.