Group leader: Koldo García Etxebarria, Ph.D.

UPV - EHU koldo.garcia@biodonostia.org

Strategic objectives:

The elucidation of the genetic mechanisms leading to gastrointestinal (GI) disease is the main goal of the group. With special focus on inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and other GI conditions, the group strives to identify risk genes and their causative variants by applying genetic, bioinformatic and functional genomic approaches. It also studies how the genetic make-up of the host affects the composition of the human microbiota, which is highly relevant to human disease. The group is interested in the potential to correlate genetics and microbiota variation with human bowel behavior and function, particularly in relation to endophenotypes of IBS (colonic transit, stool frequency etc.).

Main lines of research:

• Inflammatory bowel disease (IBD): Crohn’s disease (CD) and ulcerative colitis (UC) show a strong genetic component, and more than 200 IBD risk loci have been already discovered. We aim to exploit this information for the identification of novel diagnostic and/or therapeutic targets, and for the delineation of genotype-based strategies to personalized medicine.
• Irritable bowel syndrome (IBS): A heritable component of IBS is recognized, yet no unequivocal IBS risk genes have been identified. We believe the current IBS “label” is inadequate to capture the true spectrum of a IBS manifestations, where the weight of genetic factors may range from rare single-gene forms to extremely complex polygenic conditions. We aim to unravel key IBS pathogenetic mechanisms by combining genome-wide association studies (GWAS) of common risk variants in the general population, targeted and whole-exome sequencing for the identification of rare variants in subsets of IBS patients, and functional characterization of risk genes and associated causative alleles. We have established an extensive network of collaboration with other centers around the world, and coordinate the bellygenes initiative (www.bellygenes.org).
• Other GI conditions: A genetic component has been reported also for gastroesophageal reflux disease (GERD), microscopic colitis, diverticulitis and other GI diseases but, similar to IBS, this is underinvestigated. We are running initial GWAS and targeted analyses, with the overarching goal to fill the knowledge gap and gain increased pathogenetic understanding. For these studies as well, we have established an international network of collaboration.
• Genes, microbiota and gut function: Variation in the composition of gut microbiota is of relevance to human diseases but still poorly understood are the factors that induce and/or maintain such variation. We study this interaction to understand whether, and if so how, the genetic make-up of the host affects the composition of the human microbiota, and approach this question through computational assessment of host genome vs microbiome comparisons. We are also interested in the potential to correlate microbiota variation with human bowel behavior and function, particularly in relation to endophenotypes of IBS (colonic transit, stool frequency etc).