So far, three main NOD2 variants, which include two amino acid substitutions, p.Arg702Trp encoded by exon 4, and p.Gly908Arg encoded by exon 8, and the frameshift mutation p.Leu1007fsX1008 located in exon 11, were identified to be overrepresented in CD patients. This evidence concerns the gene NOD2 and Cowden disease.