Researchers at the University of British Columbia have uncovered a rare gene mutation that appears to dramatically increase the risk, in some individuals, of developing a severe form of progressive multiple sclerosis. While the cause of MS is not known, scientists believe several different factors, including susceptibility genes, may interact to trigger the disease. The gene was discovered in two unrelated families that had multiple members with MS. The researchers also determined that the gene (NR1H3) contains instructions for a protein called LXRA, which is thought to be a control switch for genes involved in many functions, including some that help control inflammation and integrity of nerve-insulating myelin in the brain and spinal cord. This type of discovery can provide crucial clues to biological pathways that underlie MS, and may lead to new approaches for stopping MS and restoring function. The study, by Drs. Carles Vilariño-Güell, Weihong Song, A. Dessa Sadovnick and others, was funded in part by the MS Society of Canada and appeared in the journal Neuron on June 1, 2016.