CONFIRMATION OF A SUSCEPTIBILITY LOCUS FOR CROHNS-DISEASE ON CHROMOSOME-16

Crohn's disease and ulcerative colitis are related complex genetic dis orders producing chronic intestinal inflammation. A susceptibility loc us for Crohn's disease. IBD1 (inflammatory bowel disease), has been im plicated on chromosome 16. To evaluate IBD1 in a different population using alternative methodology, we tested markers in the region of IBD1 . Seventy-two relative pairs with Crohn's disease only, 23 mixed relat ive pairs (one relative having Crohn's disease, the other, ulcerative colitis), and 5 relative pairs with ulcerative colitis were genotyped in the region of IBD1. Our population consisted of white Americans, wi th 29% of families of Ashkenazi Jewish descent. Among the Crohn's dise ase pairs, we found evidence for linkage at IBD1 using multipoint anal ysis, p = 0.0082. Negative linkage scares were obtained for mixed and ulcerative colitis-only relative pairs. For the entire data set, inclu ding mixed relative pairs and relative pairs with ulcerative colitis, then was no significant evidence of linkage. No difference was observe d in the evidence of linkage between Jewish and non-Jewish families, O ur studies confirm that IBD1 represents a susceptibility locus for Cro hn's disease, but not ulcerative colitis.