Deana Atchison-Heaps has slept on a cot in a hospital next to her daughter Kaylee most nights since April, but she still doesn't know exactly why her little girl is there.

Despite the grim prognosis from doctors who said Kaylee wouldn't make it past the age of three, she turned five last week. That ability to defy the odds has Atchison-Heaps holding on to hope.

Kaylee suffers seizures and respiratory problems which keep her bedridden, but doctors can't pinpoint the source of her problems.

Two years ago, they said a rare genetic mutation caused the illness, and they now know there's calcium developing on her brain. But doctors don't know if that's the only source of Kaylee's affliction.

Rare gene mutation

When Kaylee was two, she gradually stopped walking, talking and dancing — things her parents were used to from their happy toddler.

They took her to see several doctors, even getting her eyes and teeth checked.

"[We did] everything that we could possibly imagine," Atchison-Heaps said.

Kaylee Atchison-Heaps

Kaylee Atchison-Heaps, 5, has a rare genetic mutation. (Courtesy Deana Atchison-Heaps)

Then, a few months before her third birthday, her parents saw her lip droop and her eyes cross.

"It was almost like she had a stroke," Atchison-Heaps said.

Doctors sent her for more testing. Kaylee underwent brain tests, muscle biopsies, MRI and CT scans, and a gastrointestinal test.

After still not finding answers, doctors sent the family to Baltimore to get Kaylee's genes tested.

Those tests found a rare gene mutation.

Kaylee's doctors told her mom they didn't know of any other child in the world with the same mutation. A similar case was found a few years ago, but that child's mutation was in a different place on the gene than Kaylee's.

She now responds to her family with smiles and giggles, but still doesn't talk or walk. One of her blue eyes remains slightly crossed.

8 months, no plan

Since Kaylee's first diagnosis, the family has been in and out of the hospital, but none of those stays have been as long as the current one.

Kaylee has been in hospital since April 5, and Atchison-Heaps has made Health Sciences Centre a sort of second home.

The family's actual home is in Warren, Man., 26 kilometres northwest of Winnipeg. When Atchison-Heaps travels home on the weekends, her husband, Rick, drives into Winnipeg.

Sometimes, Rick's sister stays with Kaylee, giving the couple a day to be at home with their other two kids, who are six and 16.

Kaylee Atchison-Heaps

Kaylee Atchison-Heaps turned 5 last week, despite doctors telling her family she wouldn’t make it past age three. (Courtesy Deana Atchison-Heaps)

Atchison-Heaps said it's hard but necessary.

"You do what you have to do," she said.

As much as she'd like researchers to put a name to Kaylee's condition, she doesn't think it would change her daughter's prognosis, which is uncertain.

What Atchison-Heaps does know is that her daughter is a fighter.

"She's a tough one. [She] proves them wrong," she said.

​When Kaylee was intubated in January, doctors said intubation is permanent for many children with brain diseases. But they were able to take Kaylee off it a few days later.

Then Kaylee contracted bocavirus, which is associated with respiratory tract and gastrointestinal infections. She went through two steps of non-invasive treatment and recovered in three days. Most kids go through three steps before moving on to further treatment.

There are now pink balloons tied to her bed — a celebration of her birthday and a reminder to her parents of how long she's outlasted the doctors' prognoses.

Parents keep hope for 5-year-old daughter with rare illness0:55