The importance of mitochondrial homeostasis in PCs is further confirmed by the fact that the level of Prohibitin 1 (PHB1), a major component protein of the inner mitochondrial membrane, is down-regulated in the mucosal biopsies from CD patients (34), and Phb1 deficiency in PCs triggers PC defects and spontaneous ileitis in mice (35). The gene discussed is PHB1; the disease is Cowden disease.