Those mitochondrial IBD risk alleles include a regulator of PPIF (component of the mitochondrial permeability transition pore) [39], SLC22A5 (involved in mitochondrial β oxidation) [40], or ATG16L1 [41] and NOD2 [42], both of which are involved in mitophagy and the removal of dysfunctional mitochondria. Here, NOD2 is linked to inflammatory bowel disease.