MMP9 and inflammatory bowel disease: Among the 200+ independent genetic risk loci for IBD identified by GWAS10,11, there are loci that have nearby genes involved in bacterial sensing and autophagy, such as nucleotide-binding oligomerization domain containing 2 (NOD2), autophagy-related 16 like 1 (ATG16L1) and immunity-related GTPase M (IRGM) or inflammatory response, such as interleukin 23 receptor (IL23R), caspase recruitment domain family member 9 (CARD9), matrix metallopeptidase 9 (MMP9), tumor necrosis factor (TNF) and interleukin 1 beta (IL1B) and they are suggested to be causal genetic variants12–14.