Tina Boileau will cross the five-kilometre finish line during Ottawa Race Weekend without her son Jonathan Pitre at her side, but he will be firmly in her heart.
Pitre died in April as he was seeking treatment for a rare skin condition called epidermolysis bullosa (EB) in the United States.
"That was supposed to be our coming home event. We were supposed to be home and do the race together," she said. "I certainly had not expected to be running alone."
Members of the group DEBRA Canada will be at her side for the race, raising money for research and programs related to Pitre's condition.
"It is going to be a very overwhelming and emotional day," Boileau said.
EB left Pitre's skin delicate, often blistering. Children with the illness are often called "butterfly children" because their skin is so fragile.
Boileau said he had always wanted to be involved in a team sport but the condition held him back. When they ran the race together in 2016, it was important to him.
"The Ottawa Race Weekend was the first event Jonathan was able to take place in as a teen," she said.
She said her son's death has permanently changed her.
"Life is never going to be easy ever again, not that it was, but this is a different kind of hard."
In addition to running, Boileau will signal the air horn to start the race.
Other children diagnosed with EB will be on hand, as will some of their families.
"It's a good reminder that these are the kids we are running for and also that Jonathan wasn't alone," said Boileau.
Annie Boucher, a spokesperson for the event, said it was important to remember Pitre at the event.
"Jonathan was a true inspiration to the whole community in Ottawa," she said. "We all felt like we knew him, we all felt like he was a member of our family."
All of the 5K race bibs will feature a butterfly on them in Pitre's memory.