An umbilical cord blood donation from one Quebec brother to another has made Canadian history as the first stem-cell transplant among siblings from a public umbilical cord bank.

And it’s all because their mother thought the donation could one day help someone else.

“I really just thought, what a wonderful thing to do, even if it couldn’t benefit us it could benefit someone else, then that would be great,” Stephanie Comeau told CTV News.

When her son Nathis was born, Comeau donated the baby’s umbilical cord to the Hema-Quebec Public Cord Blood Bank, a Montreal lab specializing in collecting, freezing and storing umbilical cord blood for stem-cell transplants. It’s one of about 40 public umbilical cord blood banks in the world.

Little did Comeau know that four years down the road, the decision would help save the life of her third-born child.

Soon after her next son, Nolan, was born, the baby began breaking out into strange lumps and rashes. Doctors diagnosed him with Acute Myeloid Leukemia, a rare blood cancer, and ushered him into four rounds of chemotherapy.

They all failed.

“His chances were very, very low,” Comeau said. “We were given hope, but we weren’t given very much.”

When doctors began exploring the idea of finding a stem-cell transplant, a Hail Mary effort that could offer Nolan the chance of a healthy new blood system, they were led to the public bank. Of 10,000 stem cell samples, there was one perfect match.

Despite being in the public system for years, Nathis’s frozen sample had never been used.

“It is quite rare, so we were pretty happy and fortunate enough that the unit was still available,” said Susie Joron, a manager of donor search strategies and stem-cell distribution from the blood bank.

The transplant went on to save Nolan’s life.

“He really is the miracle,” said Christina Cinquanta, a manager from the Leukemia Society of Canada. “We want more cases like him.”

For the boys’ mother, it’s living proof of the power of a kind deed.

“It’s really just a life-saving measure. I think it’s wonderful,” Comeau said.

The Hema-Quebec Public Cord Blood Bank collects umbilical cord blood from mothers who sign up through partner hospitals. Blood is drawn from the umbilical cord after it is cut. If not collected, umbilical cords are typically considered biomedical waste and thrown away.

Umbilical cord blood can last up to 10 years when frozen, according to the blood bank.

With reports from CTV Medical Specialist Avis Favaro, producer Elizabeth St. Philip, and CTV Montreal