Genome wide association studies and meta-analyses identified risk factors related to epithelial integrity of the intestinal barrier, innate immune responses and autophagy in inflammatory bowel disorder (IBD) and celiac disease. Irritable bowel syndrome (IBS), the most common functional gastrointestinal disorder (FGID), coexists and shares common, although milder, features with IBD and celiac disease. Although our knowledge on genetic variability in IBS symptom generation is very limited, smaller scale studies attempt to provide insight in the mechanisms underlying IBS. Camilleri et al. identified associations for susceptibility loci in inflammatory and epithelial barrier genes with colonic transit in lower FGID. Their report is the first descriptive study to assess potential genetic factors involved in motor function. Further exploration of genetic variation in IBS will be crucial to unravel its' pathogenesis. © 2011 Blackwell Publishing Ltd.