In addition, important connections have been found between molecular and clinical phenotypes, such as the ones related to disease location (associations of NOD2, MHC and MST1 3p21 variants with ileal vs. colonic CD) and to disease behavior (associations of NOD2, MHC and MST1 3p21 variants with deep ileal ulcers; NOD2 variants with fibrostenotic or stricturing ileal CD; miR-215 expression with penetrating CD and differential DNA methylation with inflammation in CD) [21]. This evidence concerns the gene HLA-C and Cowden disease.