Sebastien’s Story: Researchers tackle Crohn’s disease and ulcerative colitis in children


“Our ultimate goal is of course a cure—but at the very least our study will lead to dramatically better outcomes for patients like Sebastien. That’s what drives our work every day.” 

- Dr. Alain Stintzi

Rather than spending his weekends on the toboggan hill and playing in the snow with his friends, six-year-old Sebastien spent most of this past winter on the couch. He was plagued with fatigue, weight loss and abdominal pain.

“He was too tired to even play with his Lego,” says Sebastien’s mom, Michelle Lalonde. “He had stopped growing, his teeth stopped coming in and he even had a few white hairs. We had no idea what was wrong with him.”

Only after a long series of tests, did she learn that her son was suffering from Crohn’s disease.

Crohn’s disease and ulcerative colitis are the two main forms of inflammatory bowel disease (IBD). Crohn’s can be very hard to diagnose in children because many of its symptoms are non-specific. Children like Sebastien can end up being very ill for a long time before they are diagnosed. Even when the condition is identified and a suitable treatment is found, it is still a difficult diagnosis to hear because, while the symptoms of the disease can be managed with medication, it is not curable.

Sebastien isn’t alone. Ontario has one of the highest incidences of Crohn’s disease in the world, and the number of children being diagnosed and treated at CHEO has nearly tripled over the past 15 years.

Not only is the disease becoming more common, it’s also a mystery to researchers. Its cause is unknown and treatment is complex. It sometimes takes several months to determine the most effective course of treatment. In some cases, surgery is still required to remove affected parts of the bowel.

Earlier this year, a team of researchers at the University of Ottawa and CHEO was awarded $9.1 million by Genome Canada to help crack the mystery of this disease and find better treatments. With these funds, the team expects to make a significant difference in the lives of children like Sebastien.

Dr. Mack et Sebastien at CHEO

After a number of appointments at CHEO this past winter and spring,Dr. Mack and Sebastien are old friends now. 

The 12-person research team, co-led by Dr. Alain Stintzi of the University of Ottawa and Dr. David Mack of the CHEO Research Institute, will spend the next four years getting intimate with the microbial community inhabiting the gastrointestinal tract. Alterations to it are thought to cause the chronic inflammation of the bowel wall that characterizes Crohn’s disease and ulcerative colitis. The team hopes to significantly impact the lives of IBD patients by understanding how the microbial community works and reorganizing its composition—no small feat. This highly complex collection of microorganisms is estimated in the hundreds of trillions.

Not only will the team attempt to considerably reduce the amount of time it takes to diagnose a patient and improve treatment, they are also looking to develop treatments targeting the actual cause of Crohn’s disease.

“Current treatments target different aspects of a person’s immune system that cause bowel inflammation, but they’re not targeting the cause of that inflammation,” says Stintzi. “We are essentially trying to reset the microbiome back to a non-inflammatory environment.”

Sebastien with his mom and dad

Sebastien with his father, Adam Dominique, and mother, Michelle Lalonde

“Over-treatment and under-treatment is a challenge in patients with Crohn’s disease and ulcerative colitis currently,” says Dr. Mack. “Our hope is that we can change the way we manage IBD by making treatment more efficient, less complex and safer for the patients.”

While the task of trying to understand how hundreds of millions of microorganisms may be daunting, Drs. Mack and Stintzi are optimistic about what they will achieve during the course of this four-year study.

“Our ultimate goal is of course a cure—but at the very least our study will lead to dramatically better outcomes for patients like Sebastien,” says Stintzi.  “And that’s what drives our work every day.”

“This work was funded by the Government of Canada through Genome Canada and the Ontario Genomics Institute (OGl-149)".


Media Inquiries:

Isabelle Mailloux Pulkinghorn
Acting Manager, Media Relations
University of Ottawa
613-240-0275 | 


6-year-old Sebastien Dominique was diagnosed with Crohn's disease this winter.


Back to top