NOD2 and irritable bowel syndrome: In IBD patients, there exist an aberrant immune response to microbial dysbiosis due to genetic defects in innate immunity, intestinal barrier, microbial recognition, processing, and phagocyte including nucleotide-binding oligomerization domain-containing-2 (NOD2), Caspase-recruitment domain 15 (CARD15), immunity-related GTPase M (IRGM), autophagy-related 16-like 1 (ATG16L1), and Toll-like receptor (TLR) [50].