Genetics of inflammatory bowel disease in Japanese.

Several genetic studies have identified >200 susceptibility loci for inflammatory bowel disease (IBD), mostly shared between ulcerative colitis (UC) and Crohn's disease (CD). By analyzing the genetic background associated with disease sub-phenotypes, colonic Crohn's disease located intermediate between Crohn's disease with ileal involvement and UC. However, these loci were analyzed mainly in Caucasian IBD, less is known about IBD genetics in other population including Japanese. Recently, a SNP array designed specifically for the Japanese population were developed. To clarify Japanese-specific genetic background of IBD, a genome-wide association study of Japanese IBD with this kind of population specific array is needed to be performed.