British Columbia

UBC researchers find genetic 'smoking gun' behind progressive multiple sclerosis

A researcher who has spent 40 years establishing the link between multiple sclerosis and genetics is part of a team that has found a "smoking gun" linking a single gene mutation to an aggressive form of the disorder.

Dessa Sadovnick has been advancing research into the genetics of MS for 40 years

Researchers Dessa Sadovnick (left) and Carles Vilarino-Guell are two of the researchers who found the 'smoking gun' gene. (CBC)

A University of British Columbia professor of medical genetics and neurology, Dessa Sadovnick, and her colleagues have discovered a causal or "smoking gun" gene for multiple sclerosis.

While genetic factors behind MS have been known for a while, this is the first time a single gene mutation has been found that causes at least one variation of the disorder.

"There have been a lot of genetic factors that have been associated with multiple sclerosis, but they have a really small overall effect," one of Sadovnick's colleagues, Carles Vilarino-Guell, told On The Coast host Stephen Quinn.

"If you have these mutations that we've identified, it's roughly 60 to 70 per cent [that you would develop multiple sclerosis]."

While the gene mutation in NR1H3 is only directly associated with a particularly aggressive form of progressive MS, which sees patients' health rapidly deteriorate, Sadovnick says her discovery could have implications for new treatments for all MS sufferers.

"The majority of the people with MS have relapsing-remitting MS, where they have attacks and then complete or partial recovery … Those people do tend to eventually go on to becoming progressive MS after many years," Sadovnick said.

"So, once they get into the progressive stage, they're very similar to the disease in these families. And it's the progressive phase for which there's really no known therapy. And this will hopefully help those with relapsing-remitting who become progressive as well as these primary progressive families."

Establishing a genetic link

While the existence of genetic factors behind MS is accepted now, that wasn't always the case.

Forty years ago, as a student, Sadovnick hypothesized there was a link, but colleagues and superiors consistently derided and ridiculed her hypothesis.

"In those years, genetics was felt to be relevant to pediatrics. It was not even considered for adult-onset diseases," Sadovnick said. "Yet, even in those years, we were aware that there were families where more than one person in the family would have MS."

"Genetics was relatively new … MS didn't seem to fit the pattern, but more because it was a late-onset disorder."

But Sadovnick kept at it, and, thanks to a DNA project in 1993, tipped the scales in favour of the genetic hypothesis.

It was thanks in part to stubbornness, she said, but also her interest in the disorder. Her mother and aunt suffered from it, and were founding members of the MS Society of Canada.

"I tend to say I was involved with MS before I was even born," she said.

With files from CBC Radio One's On The Coast

To hear the full story, click the audio labelled: UBC researchers find 'smoking gun' gene linked to progressive MS