Genetic variant associated with faster progression of multiple sclerosis
Researchers have identified a new genetic variant that is associated with faster progression of multiple sclerosis.
A study of more than 22,000 people with multiple sclerosis (MS) has for the first time identified a genetic variant that could be responsible for why some people progress to severe stages of the disease more quickly than others.
MS is a chronic autoimmune disease characterized by inflammatory demyelinating lesions that affect the white and grey matter of the brain. These lesions accumulate over time, causing the disease to progress. Previous studies have demonstrated that an abnormal immune system can influence MS susceptibility and disease progression can be slowed by treating immune dysfunction.
“These risk factors don’t explain why, 10 years after diagnosis, some MS patients are in wheelchairs while others continue to run marathons,” Sergio Baranzini, a professor of neurology at University of California, San Francisco (CA, USA) and co-senior author of the study commented.
The current study, which includes researchers from Yale University (CT, USA), is the first to identify a genetic variant that increases disease severity. The first part of the research combined data from more than 12,000 people with MS to complete a genome-wide association study, which links genetic variants to particular traits. Using statistics, scientists were able to link genetic variants to MS severity, including the years it took for each individual to advance from diagnosis to a certain level of disability. After examining more than 7 million genetic variants, researchers identified a variant associated with faster MS progression. They found that people with MS with two copies of the gene variant experienced faster disease progression than those without the gene variant. “Inheriting this genetic variant from both parents accelerates the time to needing a walking aid by almost four years,” Baranzini explained.
The variant sits between two genes: DYSF, which helps repair damaged cells and ZNF638, which helps control viral infection. Interestingly, these two genes have not been linked to MS before. The proximity of the variant to these genes suggests a possible mechanism for accelerated progression.
To confirm their findings, the scientists studied the genetics of 10,000 additional people with MS. The results of this confirmed that for those with two copies of the variant, MS disease progression occurred at a faster rate.
David Hafler (Yale University), co-author of the study, commented, “this is the first study to identify neuronal genetic variants associated with the neurodegenerative aspects of the disease.”
The results of this study open doors for a better understanding of MS. It gives the field its first significant lead to address the nervous system component of MS and provides new opportunities to develop novel drugs that may slow down disease progression.
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