ATG16L1 and Cowden disease: Compromised intestinal epithelial barrier functions in ATG16L1 mutant (ATG16L1T300A) mice and patients with CD homozygous for the ATG16L1T300A mutation have been associated with a reduced viability of Paneth cells, a subtype of intestinal epithelial cells which are important producers of antimicrobial peptides [103].