- As of 2020, about 2.8 million people globally have multiple sclerosis (MS).
- There is currently no cure for MS and the disease symptoms can become severe over time, causing permanent issues.
- Researchers from the University of California, San Francisco, have discovered the first genetic marker associated with MS severity and progression.
- Scientists believe this finding may aid in the development of new drugs to help slow the progression of the disease.
As of 2020, about 2.8 million people around the world have multiple sclerosis (MS) — a disease of the central nervous system affecting mobility and vision.
There is currently no cure for MS. The disease affects each person differently in terms of when symptoms first arise and their severity.
As the body goes through a cycle of symptom flares and remission, the severity of the disease can increase, leading to permanent mobility issues, vision loss, and even partial or full paralysis.
Now, researchers from the University of California, San Francisco, have discovered the first genetic marker associated with MS severity and progression.
Scientists believe this finding may aid in the development of new drugs to help slow the progression of the disease.
This study was recently published in the journal Nature.
Research targets MS progression
For this study, Dr. Sergio Baranzini — professor of neurology at the University of California, San Francisco, and co-senior author of the study — said he and his team decided to search for a genetic variant related to faster MS progression because the disease evolves differently in each person after diagnosis.
“Neurological progression is a common feature in persons with MS, which is inexorable and independent of whether relapses are controlled or not,” he told Medical News Today.
“Some people have a very aggressive disease [that] can impact their mobility and neurological function in a few years, while others experience a much more benign course,” he explained. “We knew that genetics is important for risk, but this variability of outcome suggested that genetics may also play a role in severity.”
Dr. Baranzini and his team utilized data from two large MS research consortia, The International Multiple Sclerosis Genetics Consortium (IMSGC) and The MultipleMS Consortium.
Data from both groups were combined to provide data from more than 12,500 people with MS for a genome-wide association study (GWAS).
From there, study scientists sifted through more than 7.5 million genetic variants, finally finding one associated with increased disease progression in people with MS.
This specific variant is located between two genes with no prior connection to MS called DYSF and ZNF638. DYSF helps to repair damaged cells and ZNF638 aids in controlling viral infections.
To ensure their findings were correct, Dr. Baranzini and his team then looked at the genetics of almost 10,000 people with MS. They found those with two copies of that variant experienced faster progression leading to disability.
“As [with] most genetic variants, every person has two copies of it,” Dr. Baranzini explained to MNT.
“We found that people with MS inheriting both copies — one from each parent — reach EDSS 6, a landmark metric of severity, when people with MS need assistance to walk, almost 4 years earlier than people who do not have both copies.”
– Dr. Sergio Baranzini
“This is a very substantial effect for a single genetic variant,” he added. “Furthermore, this variant affects genes that are active in the central nervous system, a clear contrast to variants that confer risk, which overwhelmingly affect the immune system.”
Potential for new MS therapies
As there is currently no cure for MS, doctors use various medications to help slow down the disease progression, treat symptoms, and help prevent relapses.
According to Dr. Baranzini, these study findings will help pave the way for a new class of therapeutics that will address progression and will likely target the central nervous system.
Dr. Baranzini pointed out that because the development of therapies carries a big risk for the pharmaceutical industry where only a small percentage of drugs make it to the market, genetic information significantly de-risks drug development.
“This discovery will set a number of development programs that will target the unmet need of disease progression in MS,” he told us. “All drugs developed to control relapses are immunomodulatory, which matches the genetics of the more than 200 variants associated with MS risk. The genetics of disease severity now suggests that the central nervous system should be the target of this new class of therapeutics.”
As for the next steps for this research, Dr. Baranzini said now that they have established that genetics play a role in disease severity, the IMSGC is now preparing for a new genetic study with even more subjects.
“Our previous experience with disease susceptibility indicates that a larger study translates into more discoveries, and we are excited to uncover more genetic variants that could help develop more effective treatments for MS,” he added.
How is MS currently treated?
Because MS affects the brain and nervous system, it can have a profound impact on a person’s ability to move, think, talk, and see.
Although scientists are still not clear as to what causes MS, most agree it has something to do with the body’s immune system mistakenly attacking the central nervous system.
This attack harms a substance called myelin that coats the nerve fibers in the brain and spinal cord. When damaged, myelin can no longer stock the nerve fiber from being exposed, resulting in messages no longer moving back and forth between the nerves and the brain.
Other risk factors for MS include:
- age — most people receive a diagnosis between the ages of 20 and 50 years
- gender — MS is more common in women than men
- family history of MS
- smoking
- vitamin D and/ or B12 deficiency
- exposure to certain viral infections such as with the Epstein-Barr virus or mononucleosis.
Why the new study is helpful
MNT spoke with Dr. Krupa Pandey, associate professor of neurology at the Hackensack Meridian School of Medicine, director of the Hackensack University Medical Center MS Center, and director of clinical research at the Neurosciences Institute, NJ, not involved in the current study, about its relevance.
“This study is helpful in a few ways,” she commented. “It is a step in the right direction of finding a link between genes and how severe a disease might be.“
“It is also helpful because it provides more evidence that environmental factors, such as smoking, really do contribute to worsening disease in genetically predisposed individuals. This is a great example of how both nature and nurture impact a disease,” Dr. Pandey noted.
“Discoveries like this may lead to future findings that can help us counsel patients on how to tailor not just medication regimens but modify lifestyle-related factors,” the expert added.
“It is also helpful for companies looking at MS therapies [to] enroll patients with higher risks for progression in order to see if the drug is effective,” she explained.
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