Researchers have discovered five gene regions that raise the risk of inflammatory bowel diseases in children and adolescents — a finding that could help them develop new drug therapies.

Crohn’s disease and ulcerative colitis are the most common types of IBD. Both are incurable chronic diseases that cause inflammation in the gastrointestinal tract, resulting in severe abdominal pain and diarrhea.

The study, published in this week’s issue of Nature Genetics, is the largest genetic analysis of early-onset IBD. Most other studies have focused on IBD in adults.

“The incidence of IBD is on the rise among Canadian youth,” said Dr. Mark Silverberg, one of the paper's senior authors and associate member of the Samuel Lunenfeld Research Institute of Mount Sinai Hospital in Toronto.

“These findings will help us identify the genetic defects and causes of IBD in children and young adults so that we can better understand why children develop IBD and develop improved drug therapies for pediatric patients."

A team of international researchers led by Hakon Hakonarson, director of the Center for Applied Genomics at the Children's Hospital of Philadelphia, performed a genome-wide association study on DNA from over 3,400 children and adolescents with IBD and compared their genetic structure to that of nearly 12,000 healthy children.

Protein behind intestinal inflammation

Dr. Anne Griffiths, co-principal author of the study and head of the gastroenterology division at SickKids Research Institute in Toronto, said one of the most important discoveries is the gene that carries the code for a "signalling" protein that plays a key role in causing intestinal inflammation.

Researchers said the study also showed the close relationship between early- and adult-onset IBD.

"This study demonstrates that genes which determine susceptibility to adult-onset disease also lead to IBD that develops in children," Griffiths said.

She said researchers are still looking at why some people develop IBD as children and some people develop it later in life. She said genetic susceptibility is just part of the reason people develop IBD, adding that different factors — including environmental triggers — could play a role in the chronic condition.

About 4,900 young Canadians have some form of IBD, according to data compiled by SickKids researchers.