While the NOD2 mutations, which have been shown to confer susceptibility to Crohn’s disease, were not found to confer susceptibility to MS [20], MS patients heterozygous for a G to A substitution in the rs5743291 allele had enhanced myelin basic protein-specific IL-17 and IL-5 responses suggesting that NOD2 polymorphism may alter Th biasing [21]. Here, IL17A is linked to Crohn disease.