Major CD susceptibility pathways uncovered through recent genome-wide association studies (GWAS; the examination of many common genetic variants in different individuals to determine any association with a trait) implicate the innate immune response (e.g., NOD2), the more specific, acquired T cell response (e.g., IL23R, ICOSLG) and more recently autophagy (e.g., ATG16L1, IRGM) [3,6]. This evidence concerns the gene ATG16L1 and Cowden disease.