Racing Toward a Cure
By David McLaughlin
“Why my child?”
These are among the most heart-wrenching questions families ask, and they are sometimes the most difficult for physicians to answer. But for families of loved ones with cystic fibrosis, there are now more answers about the origin of this once-mysterious illness.
The knowledge offers comfort, and it is raising hope for a cure.
Cystic fibrosis affects health in many ways. Patients have trouble breathing, as thick mucus coats the lungs. They become prone to chest infections, which can bring on pneumonia. And they have trouble digesting food, which limits nutrient absorption and stunts growth.
Better treatments have dramatically improved patient outcomes in the last two decades, but cystic fibrosis is still the most common fatal genetic disease affecting Canadian children and young adults.
Progress on understanding the illness leapt ahead in the 1980s, when Dr. Lap-Chee Tsui, then a Professor at the University of Toronto and a scientist at The Hospital for Sick Children, applied a new approach to disease-mapping called genetic linkage. Based on this work, Tsui and his colleagues, Dr. John Riordan at SickKids and Dr. Francis Collins at the Howard Hughes Medical Institute, found the gene that causes cystic fibrosis on chromosome 7 in 1989.
The breakthrough led to a flurry of genetic studies, which have detailed some of the mutations in the CFTR gene that cause the disease. In turn, this work has led to gene-based therapies.
Researchers at the University of Washington, for example, recently led a successful clinical trial of a new drug. The treatment only works in about three per cent of Canadians with cystic fibrosis, but for those it helps, it treats the basic cystic fibrosis defect in every cell.
St. Michael’s Hospital was a leading site for the trial. Elizabeth Tullis, a Professor in U of T’s Department of Medicine and Director of the hospital’s Adult Cystic Fibrosis Clinic, has called the new treatment a “game-changing drug.”
Tsui is now the Vice Chancellor and President of Hong Kong University.