Parents in New Westminster, B.C. are looking for help from a stranger after learning their young son needs a bone marrow transplant, and that none of their family members are a match.

Like most kids his age, four-year-old Luke McLetchie is a ball of energy.

"You wouldn't know he's sick looking at him, that's why we didn't know," his mother Jodee told CTV Vancouver on Tuesday.

But there was one unusual trait about Luke that his parents did notice.

"He bruises more than his brothers. It's weird they don't bruise. But you'd see all these bruises on his leg and think, 'Oh, he's just a little crazier than the other ones,'" said his father Iain, a producer at TSN Radio. TSN is owned by Bell Media, the parent company of CTV News.

Luke is an active kid, so his parents didn't think much of it, but they decided to bring him to the doctor in late March to get it checked out. They heard back from the doctor later that same day.

"He called us and was like, 'You need to pack your bags. You need to go to (BC) Children's Hospital. You might be there for a few days. His blood work doesn't look very good,'" Jodee recalled.

"It was awful. It was so scary. The worst drive of my life."

A couple weeks later, Luke was diagnosed with aplastic anemia, a blood disorder so rare there are only between two and 12 new cases per million people. 

The disorder results when the marrow fails to produce blood cells, and it can be acquired or inherited, the Aplastic Anemia and Myelodysplasia Association of Canada says.

Luke's family was advised not to look up the disorder on the internet, "but of course you do," Iain said. They learned their son could bleed to death from a simple head wound.

"His risks right now are that he could bleed out because he doesn't have enough platelets… Being exposed to any sort of infections – because he doesn't have an immune system, it could kill him," Jodee said.

"If he had a fever, we need to take him straight to the ER. We need to keep him away from other children. He can't go to daycare."

If Luke goes grocery shopping with his mom, they're supposed to go during the week when there are less people in the store, and he has to wear a mask while he's out. They also have to use a lot of hand sanitizer, Jodee said.

She's had to quit her job to stay home with her son.

Luke will start immunosuppressive therapy this week, but it won't be easy on the pint-sized patient.

"Once he goes through the medications, the side effects, the nausea, vomiting, all the stuff that's going to come with it… That's going to be really, really tough," Iain said.

"But unfortunately, that's a step that he's going to have to go through at this stage."

A bone marrow transplant could cure him, but his parents and brothers aren't a match. So BC Children's Hospital is looking for a stranger match on worldwide donor lists.

The McLetchies hope Luke's story will convince more people to sign up.

"It's a simple blood test. His brothers got it done. They didn't even cry, so if they can do it, anyone can do it," Jodee said.

"I'm hopeful there's someone out there and I'm hopeful he'll be able to start soccer."

Meanwhile, she says the family is grateful for friends, family and co-workers.

"The amount of support we've received… I have no words to express that because it's been incredible," she said.

Want to join the bone marrow donor registry? Here's more information on how to sign up.

With a report from CTV Vancouver's Shannon Paterson