title: Differences between adults and children: genetics and beyond.
abstract: Clinical observations and epidemiological studies have highlighted some important differences in disease course and phenotypes between pediatric inflammatory bowel disease (IBD) and adult-onset IBD. Also from a therapeutic angle, the approach to young-onset IBD is different with a more rapid introduction of azathioprine and a high threshold for long and systemic steroid use, which may affect bone mineral density and growth. The observed clinical differences have been an area of scientific research and genetic studies have been the focus of attention. Specific candidate gene studies as well as genome-wide association studies have been performed in pediatric IBD. With the exception of very early-onset IBD occurring before the age of 2 years; no overt differences in genetic susceptibility have been identified. In contrast, very early-onset IBD seems in particular to be a genetic disease with defects in the IL10 signaling pathway being the principal example. This review aims to answer some straightforward questions arising in this topic by giving concise information.
authors.affiliation: Department of Gastroenterology, University Hospitals Leuven, Herestraat 49 - B-3000 Leuven Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Billiet
authors.forename: Severine
authors.initials: S
authors.lastname: Vermeire
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D002648:Child; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology* / Q000235:genetics* / Q000503:physiopathology; D016753:Interleukin-10 / Q000502:physiology; D010641:Phenotype; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D016753:Interleukin-10
keywords: Crohn’s disease; IL-10R mutations; genetics; genome-wide association studies; inflammatory bowel disease; ulcerative colitis; very early-onset IBD