Oncology

Locating the genetic markers of a choking disease

A Université de Montréal researcher looking into a hereditary disease that swells the throat to the point of choking has been recognized internationally after the US National Institutes of Health (NIH) announced it will fund his study.

The NIH has announced it will support a clinical study by Montreal geneticist and neurologist Guy Rouleau to identify the genetic markers of angioedema, a rare but serious disorder that disproportionately affects people of African origin. The two are currently preparing for the large study that will not only involve 48 patients suffering from angioedema but some 250 of their family members.

The UdeM researcher, renowned for his discovery of several genes responsible for autosomic diseases, will direct a research group together with Albert Adam, a professor in the University’s Department of Pharmacy. “The more we know about angioedema, the better we will be able to understand how it is transmitted,” explains the physician and researcher. Professor Adam, meanwhile, will pursue research to identify promising pharmaceutical treatments. “In a way, we are combining our expertise,” he explains, adding that this partnership creates a good balance of basic and applied research.

Persons suffering from angioedema have a problem with capillary permeability that can result in tissue swelling. All organs, including the brain, lungs and kidneys, are subject to swelling. The consequences can be serious, and may lead to coma and death. But the most common symptom is inflation of the larynx, its symptoms being difficulty swallowing and even breathing. Angioedema can be triggered in different ways, one of them being by physical or emotional stress. In women, episodes of edema may be linked to menstruation or the use of oral contraceptives. And children may be affected during teething.

One thing known about angioedema: It is linked to a mutation of a gene on chromosome 11, which is responsible for producing of an enzyme, C1 esterase inhibitor. But researchers are intrigued by the disease being more common among Blacks. “The incidence is about 0.1 to 0.2% in the general public,” explains Guy Rouleau. “But the rate climbs to 0.7 to 2% among those of African origin. This is a very significant factor.”

Known for his work in the neurogenetics laboratory at McGill University, Dr Rouleau helped identify genes responsible for several particular disorders in Quebec. The gene for oculopharyngeal muscular dystrophy was identified by his laboratory in 1993; half the worldwide cases live in Quebec. The genes responsible for juvenile myoclonic epilepsy and Lou Gehrig’s disease were also identified in his laboratory. A native of Vanier, near Ottawa, Dr Rouleau trained as a neurologist. He still practices medicine in Buckingham Hospital in the Ottawa Valley, where he does general neurology one day a month.