In findings published today in Nature, an international collaboration of researchers report a genetic variant that increases disease severity, providing the first real progress in understanding and eventually fighting this aspect of MS.
The work was the result of a large international collaboration of more than 70 institutions from around the world, led by researchers from UCSF (USA) and the University of Cambridge (UK).
“Inheriting this genetic variant from both parents accelerates the time to needing a walking aid by almost four years,” said Professor Sergio Baranzini at UCSF, co-senior author of the study.
“Understanding how the variant exerts its effects on MS severity will hopefully pave the way to a new generation of treatments that are able to prevent disease progression,” said Professor Stephen Sawcer from the University of Cambridge and Cambridge University Hospitals NHS Foundation Trust, the other co-senior author of the study.
To address the mystery of MS severity, two large MS research consortia joined forces: The International Multiple Sclerosis Genetics Consortium (IMSGC) and The MultipleMS Consortium. This enabled MS researchers from around the world to pool the resources needed to begin to identify the genetic factors influencing MS outcomes.
Previous studies have shown that MS susceptibility, or risk, stems in large part from dysfunction in the immune system, and some of this dysfunction can be treated, slowing down the disease. But, explained Baranzini, “these risk factors don’t explain why, ten years after diagnosis, some MS patients are in wheelchairs while others continue to run marathons.”
The two consortia combined data from over 12,000 people with MS to complete a genome-wide association study (GWAS), which uses statistics to carefully link genetic variants to particular traits. In this case, the traits of interest were related to MS severity, including the years it took for each individual to advance from diagnosis to a certain level of disability.
After sifting through more than seven million genetic variants, the scientists found one that was associated with faster disease progression. The variant sits between two genes with no prior connection to MS, called DYSF and ZNF638. The first is involved in repairing damaged cells, and the second helps to control viral infections. The variant’s proximity to these genes suggests that they may be involved in disease progression.