Multiple sclerosis (MS) is a chronic disease where the immune system attacks the myelin sheath – the fatty substance that protects nerve fibers in the central nervous system.
As a result, the nerve fibers can become damaged, which interrupts signaling between the brain and spinal cord.
This can lead to movement problems, as well as muscle weakness and numbness or tingling in face, body, and extremities.
According to the National Multiple Sclerosis Society, 2.3 million people across the globe are affected by MS, with onset of the condition being most common between the ages of 20 and 50.
At present, there are no laboratory tests that can detect MS, meaning that it can take years to reach a definitive diagnosis. In the meantime, damage to the central nervous system worsens.
Following an MS diagnosis, there are medications available that can help slow disease progression by suppressing the immune system, but these can have severe side effects.
A new study has revealed the discovery of genetic variants associated with an increased risk of MS. Researchers suggest these variants could fuel the development of new ways to diagnose and treat the disease.
Co-lead study author Simon Gregory, director of genomics and epigenetics at the Duke Molecular Physiology Institute at Duke University Medical Center in North Carolina, and colleagues reported their findings today in the journal Cell.
DNA variants and the immune system
Gregory and his team did a genetic analysis of individuals with and without MS.
They identified two DNA variants in two genes - DDX39B and IL7R – that increase a person’s risk of MS by threefold.
The researchers found that the interaction of these variants leads to an overproduction of a protein called sIL7R. This protein communicates with the immune system, which the researchers believe plays a key role in the development of MS.
"Our study identifies an interaction with a known MS risk gene to unlock a new MS candidate gene, and in doing so, open[s] up a novel mechanism that is associated with the risk of multiple sclerosis and other autoimmune diseases," said Gregory in a press statement.
According to the researchers, their findings may have important implications for patients, such as more accurate diagnostic techniques for MS and other immune-mediated conditions.
"One could envision how this type of knowledge will someday lead to [diagnosing] multiple sclerosis sooner and, now that we have promising therapies, a doctor could start the appropriate treatment more quickly,” said study co-leader Dr. Mariano Garcia-Blanco, of the Department of Biochemistry and Molecular Biology at the University of Texas Medical Branch.
“It is not out [of] the realm of possibility to imagine a path for screening for other autoimmune diseases such as type 1 diabetes," he added.
The researchers note that their findings may also open the door to tests that can screen individuals with a family history of MS.
This early detection of DNA risk variants may help people to be more aware of MS symptoms.