In the largest, most comprehensive genetic analysis of childhood-onset inflammatory bowel disease (IBD), Emory and Childrenâ€™s Healthcare of Atlanta gastroenterologist Subra Kugathasan, MD, and colleagues identified five new gene regions, including one involved in a biological pathway that helps drive the painful inflammation of the digestive tract that characterizes the disease.
IBD is a painful, chronic inflammation of the gastrointestinal tract, affecting about 2 million children and adults in the United States. Of that number, about half suffer from Crohnâ€™s disease, which can affect any part of the GI tract, and half have ulcerative colitis, which is limited to the large intestine.
Most gene analyses of IBD have focused on adult-onset disease, but this study concentrated on childhood-onset IBD, which tends to be more severe than adult-onset disease.
Kugathasan and a team of international researchers performed a genome-wide association study on DNA from over 3,400 children and adolescents with IBD, plus nearly 12,000 genetically matched control subjects, all recruited through international collaborations in North America and Europe.
In a genome-wide association study, automated genotyping tools scan the entire human genome seeking gene variants that contribute to disease risk.
The study team identified five new gene regions that raise the risk of early-onset IBD, on chromosomes 16, 22, 10, 2 and 19. The most significant finding was at chromosome locus 16p11, which contains the IL27 gene that carries the code for a cytokine, or signaling protein, also called IL27.
Kugathasan says one strength of the current study, in addition to its large sample size, is the collaboration of many leading pediatric IBD research programs, which included Emory, The Childrenâ€™s Hospital of Philadelphia, the Hospital for Sick Children of the University of Toronto; the University of Edinburgh, UK; Cedars Sinai Medical Center, Los Angeles; and the IRCCS-CSS Hospital, S. Giovanni Rotondo, Italy.
The study, â€œCommon variants at five new loci associated with early-onset inflammatory bowel disease,â€ was published in the November 2009 online issue of Nature Genetics.
Learn more about Kugathasan’s work at Emory.