On Jun. 1, 2016, scientists at the University of British Columbia and Vancouver Coastal Health announced proof that multiple sclerosis (MS) can be caused by a single genetic mutation – a rare alteration in DNA that makes it very likely a person will develop the more devastating form of the neurological disease.

The mutation was found in two Canadian families that had several members diagnosed with a rapidly progressive type of MS, in which a person’s symptoms steadily worsen and for which there is no effective treatment.

The discovery of this mutation should erase doubts that at least some forms of MS are inherited. The findings, published in the journal Neuron, could point the way toward therapies that act upon the gene itself or counteract the mutation’s downstream effects. More immediately, screening for the mutation in high-risk individuals could enable earlier diagnosis and treatment before outward symptoms appear.