Diagnosing Cystic Fibrosis: How has it improved?

For the days leading up to our first annual CF for CF, I thought this would be a great opportunity to explore how our approach to the disease has evolved over the years.

For starters, cystic fibrosis was once considered a "childhood disease", meaning that many of us would be considered very lucky to make it to adulthood. In fact, there wasn't even an adult CF clinic when I was a child (roughly 20 years ago), so I had CF adults sharing the ward with me in Sick Kids. Now our adult clinic in Toronto is huge, and though I don't have specific figures, last I heard the number of patients hovers around the range of 400. This reflects the latest figures released from the Canadian Cystic Fibrosis Foundation (CCFF) that revealed the number of Canadian adults with cystic fibrosis (aged 18+) surpasses the number of children with CF.

To paint an even starker contrast, in the 1960s, most children with cystic fibrosis did not live long enough to attend kindergarten. Today, half of all Canadians with cystic fibrosis are expected to live into their 40s and beyond. We are finishing high school, going to university or college, working full time (or part time), getting married and sometimes having children.

So how did we get here?

Let's start from the beginning. One in 25 Canadians carries a defective version of the gene responsible for CF. In order for a child to be born with CF, both parents must be carriers of the defective gene. A person with CF has two copies of the defective gene, while a "carrier" only has one copy. For instance, my mom carries one copy of the defective gene and my dad also carries one copy, both copies were passed on to me. However, in the case of my sister, she only received one copy which makes her a "carrier", she does not have Cystic Fibrosis. 

It's a bit of a lottery when both parents are carriers, some people will have several children with CF, while others could have children that are simply carriers or are not carriers at all. 

The diagram below, shows us that if both parents are carriers of the defective gene (more specifically, the abnormal CFTR gene) there is a 1 in 4 chance they will have a child with CF, a 1 in 4 chance they will have a child that does not have CF and is not a carrier and a 2 in 4 chance they will have a child who is a "carrier" of the CF gene.

Image courtesy of Diabetes Monitor

Comprehend? It's confusing, we know. . .

For those who knowingly have a history of CF in their family, they are advised to undergo genetic testing before starting a family of their own. But, since CF was recently a childhood disease, many people are unaware that there is a history of the disease.

As a result, it can be difficult to diagnose CF. Some children are diagnosed not too long after birth because they develop Meconium ileus (a bowel obstruction), which can be a hallmark sign that something is not quite right. For others with less obvious symptoms, misdiagnosis can drag on for months or years. In my case, I was diagnosed when I was two years old, after failing to thrive, having a distended belly from malnourishment and chest infections. Some people are not even diagnosed until adulthood!

CF affects about 1 in every 3,600 babies born in Ontario, so while it's still considered relatively rare, early diagnosis and aggressive treatment leads to better health. The sooner proper nourishment needs can be met and lung damage can be prevented by starting physio and antibiotic therapy, the better. This is why the CCFF has been pushing for every province to add testing for CF to the newborn screening test. Thus far, Alberta, Ontario, Saskatchewan and British Columbia screen newborns for cystic fibrosis.

After a simple blood test, if there is a postive result, parents are asked to bring their newborn back for more testing--like the sweat test--to confirm a diagnosis. For more information on the screening process in Ontario, click here.

The hope is, that with earlier diagnosis, fewer people will fall between the cracks and future generations will enjoy an even longer period of a good quality of life.