title: The genetics of Crohn's disease and ulcerative colitis--status quo and beyond.
abstract: The two major subtypes of inflammatory bowel disease (IBD), ulcerative colitis (UC, MIM#191390) and Crohn's disease (CD, MIM#266600), are chronic relapsing-remitting inflammatory disorders affecting primarily the gastrointestinal tract. Prevalence rates in North America and Europe range from 21 to 246 per 100,000 for UC and 8 to 214 per 100,000 for CD. Although CD and UC share some clinical and pathological features, they can be distinguished by localization, endoscopic appearance, histology and behavior, which suggest differences in the underlying pathophysiology. The importance of genetic risk factors in disease etiology is high and has been documented more clearly for CD than for UC (relative sibling risks λ(s): 15-35 for CD, 6-9 for UC). The most recent and largest genetic association study for IBD, which employed genome-wide association data for over 75,000 patients and controls, established the association of 163 susceptibility loci with IBD. Although the disease variance explained by the 163 loci only amounts to 13.6% for CD and 7.5% for UC, the identified loci and the candidate genes within yielded valuable insights into the pathogenesis of IBD and the relevant disease pathways. We here review the current research on the genetics of IBD and provide insights into on current efforts as well as suggest topics for future research.
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel , Kiel , Germany.
authors.forename: David
authors.initials: D
authors.lastname: Ellinghaus
authors.forename: Jörn
authors.initials: J
authors.lastname: Bethune
authors.forename: Britt-Sabina
authors.initials: BS
authors.lastname: Petersen
authors.forename: Andre
authors.initials: A
authors.lastname: Franke
mesh_terms: D003093:Colitis, Ulcerative / Q000235:genetics*; D003424:Crohn Disease / Q000235:genetics*; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006680:HLA Antigens / Q000235:genetics; D006801:Humans
chemical_list: D005819:Genetic Markers; D006680:HLA Antigens
keywords: Crohn’s disease; SNP; chronic inflammation; early-onset IBD; genetic risk; genome-wide association studies; inflammatory bowel disease; risk loci; ulcerative colitis