The U.S. Food and Drug Administration's approval of a new drug to treat spinal muscular atrophy is offering a glimmer of hope to patients in Canada, but its steep price may be unaffordable for many families.

SMA is a rare, hereditary disease that causes muscle weakness and often leads to paralysis and even death. The progressive disorder kills more infants than any other genetic disease. SMA affects between one in 6,000 and one in 10,000 people, according to the U.S. National Institute of Health.

In December, the FDA approved a drug called Spinraza, also known as nusenersin, which is delivered by injection into the fluid surrounding the spinal cord. Studies have shown the drug halted the disease in some children and even reversed it in others.

Dr. Craig Campbell, the head of pediatric neurology at the Children's Hospital at London Health Sciences Centre, told CTV News that the studies have been promising.

"[It's] obviously a very important outcome that further underscores the importance of having our patients get access to this drug," Campbell said.

The potentially life-saving drug has not been approved in Canada yet, which is causing concern for many Canadian families, including one in Mississauga, Ont.

Stella Bartlett was diagnosed with SMA five years ago, when she was one-year-old. She is now unable to walk because of SMA. Her father, Myles Bartlett, said the disease has made his daughter incredibly weak.

"All of her gross motor [skills] are affected. She can't move her legs. She'll never walk. Raising her arms is difficult. Keeping her head up is difficult," Myles explained.

Stella's mother, Sarah Bartlett, said because of SMA's progressive nature, they don't have a lot of time to wait for the Canadian government to approve the drug while their daughter's mobility worsens.

"The longer they take [to approve the drug], whether it is six months, a year or longer, our anxiety and everyone's anxiety will continue to rise," Sarah said.

To add to their worries, Spinraza is currently one of the most expensive drugs on the market. Its maker, Biogen, recently set the price for the drug at a staggering US$750,000 for the first year of treatment, which amounts to five or six doses. Spinraza costs $375,000 for every year after that.

The Canadian price won't be set until the drug is approved, but many are expecting comparable prices.

"We used to go to bed every night thinking about whether or not they're going to make a discovery," Myles Bartlett said. "Now, we go to bed every night thinking about when are we going to get it and are we going to be able to afford it."

Dr. Peter Maybarduk, the director of Access to Medicines and Knowledge Economy Group in Washington, D.C., called the situation an "abuse of power."

"It's an outrageous price, " Maybarduk said. "It's a price that forces families to choose between their bank accounts and the wellbeing of their children."

In a written statement to CTV News, Biogen said they're focusing on obtaining regulatory approval for Spinraza/nusinersen in Canada before the price is set.

"We recognize that cost and access to treatments are key considerations for patients, providers, reimbursement agencies and policy makers and we are committed to partnering with healthcare systems and government to ensure that patients who may benefit from nusinersen [Spinraza] will have access to this new treatment option," the statement read.

If the price ends up being anywhere close to that in the U.S., the Bartlett family will have to make some tough decisions.

"We dreamed of this day when there would be a treatment," Sarah Bartlett said. "Now we're here, and we can't pay for it. We can't afford what it now is going to cost."

With a report from CTV News' medical specialist Avis Favaro and producer Elizabeth St. Philip