Families of children with a rare disease called phenylketonuria, or PKU, believe a lack of understanding about the disorder means some Canadians are being overlooked for federal help.

People with PKU cannot process an amino acid found in protein. If it's not kept in check, brain damage and other serious health problems can occur.

Despite the danger and the time it takes to manage the disease, a national advocacy group says nearly half of the families who've recently applied for the federal disability tax credit have been denied.

Calgary family denied

For mother Sandra Hughes, taking care of her 16-year-old daughter is an intense job.

PKU Disability Tax Credit calgary mother

Sandra Hughes must weigh every morsel of food her daughter eats. (Jennifer Lee/CBC)

"It has been very stressful over the years," said Hughes, whose kitchen cupboards are lined with special low protein foods.

Her daughter, Gwynneth Harland, is unable to eat everything from meat and dairy to regular bread and regular pasta. Preparing meals involves weighing every morsel of food and entering it into a spreadsheet on her laptop. There's a synthetic protein formula to prepare, regular blood tests to go for and daily medication to remember. Without all these measures, the consequences would be dire.

PKU Disability Tax Credit calgary mother

Gwynneth Harland's daily regimen involves drinking 2 doses of a synthetic protein formula. (Jennifer Lee/CBC)

"If she gets too little protein ... she won't grow. If she gets too much, it will cause brain damage. So it's a balancing act," said Hughes.

When Hughes heard some PKU families had been approved for the disability tax credit, she quickly got to work on her own paper work. Months later she was rejected.

"As a single parent, that I can't get a little bit of assistance to provide for my daughter, it's heartbreaking," Hughes said.

"I feel a little let down by the government."

PKU Disability Tax Benefit calgary mother

To prevent brain damage, Gwynneth Harland eats special low protein foods, takes two doses of a synthetic protein formula, takse daily medication and has all of her food weighed. (Jennifer Lee/CBC)

The rejection means Hughes will not see a reduction in the amount of income tax she pays and she is not eligible for child disability benefit — which can provide up to $225 a month to help with expenses. Families who are approved may also apply for up to ten years of back benefits.

Calls for change

Advocates believe the system is flawed.

"It doesn't seem to matter where you live, it seems to matter which reviewer you get," said Nicole Pallone, vice-president of Canadian PKU and Allied Disorders.

PKU Disability Tax Credit calgary mother

Nicole Pallone, whose 8-year-old daughter Rosie has PKU, received $25,000 in back benefits from the federal government after being approved for the disability tax credit. She's now fighting to help more families get approved. (Submitted by Nicole Pallone)

"So we have some work to do with the [Canada Revenue Agency] to help them understand this disorder." 

According to Pallone — who recently received $25,000 worth of federal back benefits after applying for her own daughter — very few PKU families were aware this was an option until recently.

In the last year 10 of the 19 Canadians her group has monitored have been approved for the disability tax credit.

By contrast, most children with type 1 diabetes qualify for the benefit.

"PKU is a really rare condition that not a lot of people are aware of," said Pallone, who is hoping to meet with federal officials to explain the disease and its impact on families.

Reviews on case-by-case basis

The Canada Revenue Agency, which oversees the disability tax credit, says each case is examined individually based on written submissions from both the patient and physician.

"It really depends how a condition or a diagnosis affects that patient and what impact that has on their life. If it is significant or severe they could be eligible," said CRA spokesperson Joanne deWaal.

"It's not actually the disease itself that we are reviewing. It's the impact the disease is having on the patient."

Sandra Hughes believes the CRA needs to re-assess how it handles rare disorders and ensure its workers have a good understanding of the diseases they're reviewing.

In the meantime, she is appealing her daughter's case.

"Knowing we have that little bit of buffer, a little bit of extra help to get us through, can ease my stress and therefore her stress."