It is widely accepted that inflammatory bowel disease (IBD) emerges from the interaction of a number of genes resulting in an overactive immune response towards intestinal bacteria. Standard methodologies to unravel the genetic factors contribting to susceptibility to IBD are able to point out the gross chromosomal regions involved, but they put forward no evidence about the actual causal variants. Therefore, little can be said about their mechanism of action and thus they can only aid in predicting the individual risk to develop IBD. As yet, they are of no use in IBD therapy.
To address these issues, a complementary approach will be used to identify causal genetic variants for IBD by combining genetic information with to what extend the gene product is actaully present in the cell. The latter knowledge is very significant, because genetic variants are mostly found in areas of the gene that play a role in controlling their level within the cell. A disorganization of this process can have an effect on the reaction of cells against specific stimuli and are therefore thought to have an impact on disease susceptibility.
Understanding gene expression pattner in IBD patients is valuable since each abnormally expressed gene is a potential target for therapy, either by blocking the protein which it encodes (e.g. anti-TNF) or by administering the recombinant protein (e.g. IL10). In addition, predicting such aberrant gene expression based on genetic markers aids in the understanding of the disease and has potential to provide new therapeutic targets.