Equivalently, but except for SNP rs17831757, the high ratio of n-6 to n-3 PUFAs increased the odds ratio of Crohn's disease in the subjects who have the alleles of 3 SNPs in FADS2, which are associated with high plasma levels of n-3 PUFAs and low plasma levels of n-6 PUFA [35]. Here, FADS2 is linked to Crohn disease.