INPP5D and Cowden disease: Interestingly, this downregulation was correlated with the presence of a single nucleotide polymorphism (SNP) in the ATG16L1 gene, one of the best described CD risk genes, which lies adjacent to the SHIP1 gene, INPP5D. Furthermore, SHIP1 activity was inversely correlated to the expression of IL1b, which contributes to disease severity.