Genes involved in resolving ER stress, for example, UPR-related XBP1 (26) and AGR2 (27), autophagy-related ATG16L1 (28), IRGM1 (29), and LRRK2 (30) are known susceptibility genes for CD, and deletions or mutations in these genes lead to Paneth cell abnormalities. This evidence concerns the gene XBP1 and Cowden disease.