Crohn's disease (CD), together with ulcerative colitis, has been a principal beneficiary of this technology with a recent meta-analysis from the International IBD Genetics Consortium increasing the number of confirmed CD susceptibility loci to 71.
Substantial progress has been made in the last years in characterizing the susceptibility genes involved in IBD pathogenesis, especially for Crohn's disease.
Human IBD, including UC and Crohn's disease, is characterized by a chronic, relapsing, and remitting condition that exhibits various features of immunological inflammation and affects at least one/1000 people in Western countries.
The allele frequencies of six UC-associated and 34 CD-associated single nucleotide polymorphisms (SNPs) were determined in a Canadian IBD cohort (n = 2374).
To do a genome-wide gene expression study of active and inactive ulcerative colitis and Crohn's disease (inflammatory bowel disease--IBD) and examine the most differentially expressed genes.
Genome-wide association studies (GWAS) in several populations have demonstrated significant association of the IL23R gene with IBD (Crohn's disease (CD) and ulcerative colitis (UC)) and psoriasis, suggesting that perturbation of the IL-23 signaling pathway is relevant to the pathophysiology of these diseases.
The severity of Crohn's disease was quantified by dividing the total number of ileocolectomy procedures by the time between IBD diagnosis and the patient's last clinic visit, the rationale being that more severe disease would be associated with a more frequent need for surgery.
These results suggest that PTPN2 may have an important role in CD pathogenesis and may represent a potential diagnostic and therapeutic target for IBD.
The early identification of NOD2 (nucleotide-binding oligomerization domain-containing protein 2) as a susceptibility gene for Crohn's disease first catalysed major interest in the role of innate immunity in IBD.
Genome-wide association studies identified the autophagy gene IRGM to be strongly associated with Crohn's disease (CD) but its impact in ulcerative colitis (UC), its phenotypic effects and potential epistatic interactions with other IBD susceptibility genes are less clear which we therefore analyzed in this study.
When a sufficiently powered cohort is evaluated, familial aggregation in IBD is associated to an earlier disease onset, more EIMs and more severe phenotype in CD.
We performed a genetic association study in a large multicentre cohort of patients with Crohn's disease (CD) and UC from five European IBD referral centres in a total of 2320 CD patients, 2112 UC patients and 1796 healthy controls.
The expanding knowledge of the role of genetic variants involved in the susceptibility to IBD heralds an era of disease categorization beyond Crohn's disease and ulcerative colitis.
The epigenetic changes observed in this study indicate that CD and UC exhibit specific DNA methylation signatures with potential clinical applications in IBD non-invasive diagnosis and prognosis.
These novel approaches are fully applicable to IBD and allow us to achieve the ultimate goal of developing and applying personalized medicine and far more effective therapies to individual patients with Crohn's disease and ulcerative colitis.
Inflammatory bowel disease (IBD) generally comprises Crohn's disease (CD) and ulcerative colitis (UC), and their main characteristic is the intestinal mucosa inflammation.