ATG16L1 and Cowden disease: Since the identification of NOD2 as the first susceptibility gene for CD in 2001 [5], [6], various studies including genome-wide association studies (GWAS) based on high-density SNP (single nucleotide polymorphism) arrays have identified CD-associated genetic variants of proteins involved in immune response, autophagy or bacterial recognition, such as IL23R[7], [8], ATG16L1[9]–[11], and IRGM[12].