The family of a Nova Scotia girl with an ultra-rare genetic disorder says they have hope for the first time that her condition will improve.
Harper Tanton, who is eight years old, will be the fourth child in the world to participate in a clinical trial for kids who have CTNNB1 syndrome. She largely depends on a wheelchair and has developmental and speech delays.
It’s a critical moment for the Cole Harbour family, who have spent years looking for answers about the disorder.
“It was predicted that she would never walk, she would never talk,” said her mother, Tara Tanton. “She wasn’t able to sit up until she was probably 16 months old.”
Harper was initially misdiagnosed with cerebral palsy, even though an MRI showed no abnormal brain development or damage. Her mother refused to accept it.
“I would be up until 3 o’clock in the morning every single night, going to the bottom of the internet to find something that resembled what was happening with my daughter.”
Genetic testing eventually led them to CTNNB1 syndrome, a gene mutation that means the body doesn’t produce a specific protein that is critical for development.
Tara knows of fewer than 40 cases in Canada, three of which are in Nova Scotia.
They were told there was no cure.
“There aren’t many drug companies in the Western world that are going to fork out millions and millions of dollars for 30 kids.”
The family connected with the CTNNB1 Foundation, based in Ljubljana, Slovenia, which was founded by Spela Mirosevic and her husband shortly after their son, Urban, was diagnosed in 2021.
“For me, it was impossible to look at my child and not do anything,” said Mirosevic, a health researcher. She said her family invested all their savings to create the non-profit organization.
They’ve spent years fundraising, and other families who have the same diagnosis have contributed.
Researchers at the foundation, many of them volunteering their time, are using gene replacement therapy to see if it can either stop the progression of CTNNB1 syndrome or potentially cure it.
They’re basing the treatment on existing platforms used for patients with conditions such as spinal muscular atrophy.
“A lot of people didn’t believe that we would be able to do it, because normally pharmaceutical companies develop treatments like that,” she said.
Their clinical trial has been tested on two children so far. The first was Mirosevic’s son in December. Because he was the first human in the trial, she said they had to accept that all the risks were unknown, and her son could die.
“He [was] getting worse every month, every year. We knew that if we would not treat him, he would get worse to the point where he might be in severe pain for the rest of his life,” she said.
Eight months later, she said her son is now walking with some support, he has spoken his first words and can eat some foods unassisted.
Harper will undergo the procedure in the fall.
Her mom says her body ideally will produce a normal level of protein within six weeks, increasing her ability to physically and mentally develop.

“We have to do it,” said Scott Tanton, Harper’s father, who says they looked closely at the potential risks.
“We are being cautiously optimistic, we know it may not be the magic bullet but that’s kind of what we’re hoping for, of course.”
Harper needs to have weeks of tests before the actual procedure. She and her mother will stay in Slovenia for at least six months, while her father and brother, David, stay behind in Cole Harbour.
Procedure expected to cost $300K
They estimate it will cost $300,000.
“Yeah, it’s a big sacrifice for our family, but again I think if you asked anybody, they would do whatever they can for their child. That’s what we’re doing,” Scott said.
Mirosevic told CBC News that while the foundation covers the cost of the gene replacement therapy, the Tanton family will have to pay around 100,000 euros ($161,000 Cdn) in hospital fees, in addition to travel and accommodation expenses.
As part of a clinical trial, they will also have to make repeated trips back to Slovenia for regular assessments.
The financial burden has sparked a community response. People have held bottle drives, lobster dinners and yard sales to raise money.
“I’ve had kids hand me envelopes of change from birthday money or from allowance that they’ve saved,” said Tara, who is emotional about the response.
She hopes their story inspires others grappling with a rare disease.
“These children deserve a voice. If I had stopped, we would not be where we are. If we had listened six years ago, we would have put Harper in a wheelchair at that point.”
MORE TOP STORIES

