NOD2 allelic frequencies in controls (3020insC, 0.009; 2722G>C, 0.009; 2104C>T, 0.042) did not significantly differ from patients with AS (3020insC, 0.009; 2722G>C, 0.004; 2104C>T, 0.031).
A case-control study of NOD2 polymorphisms known to be associated with Crohn's disease (CD) (Pro(268)Ser, Arg(702)Trp, Gly(908)Arg, and Leu(1007)fsinsC) was performed in 229 cases of primary AS with no diagnosed inflammatory bowel disease (IBD), 197 cases of AS associated with IBD (referred to as colitic spondylarthritis; comprising 78 with CD and 119 with ulcerative colitis [UC]), and 229 ethnically matched, healthy controls.