Genetic aspects of inflammatory bowel disease: how far have we come, and where are we heading?

Crohn"s disease and ulcerative colitis are related complex genetic disorders, with gene-gene and gene-environment interactions that are critical to their pathogenesis. Multiple genetic loci have been implicated through genome-wide searches. Of these, a locus on Crohn"s disease has been definitively established in the pericentromeric region of chromosome 16. Multiple candidate gene studies have been forwarded, and functionally significant variants in immune-associated genes will provide additional insight. Characterization of the genetic variation responsible for causing inflammatory bowel disease will result in development of novel therapeutic approaches as well as in tailoring of specific therapies to individual patients based on their specific molecular pathogenesis.