The two and a half million people worldwide who suffer from
multiple sclerosis (MS) have more in common than their disease—they also share similar genetic traits. A recent study published in the journal
Nature found 29 new genetic variants linked to MS in addition to confirming 23 already known genetic links. This is great news for MS sufferers, as scientists can now target research on treatment options to specific areas of the immune system.
Known similarities with an unknown cause. MS is an autoimmune disease that affects the brain and spinal cord. It is the most common disabling neurological disease among people ages twenty to forty. MS is caused when the myelin sheath, the protective covering that surrounds nerve cells, is attacked and damaged by
inflammation, which slows and interrupt nerve signals. As a result, the nerve signals responsible for functions like walking, eating, vision, and memory are impaired and eventually destroyed. Inflammation happens when the body’s immune cells attack the nervous system. Since scientists do not know exactly why this occurs, the discovery of common genetic links can be a starting point for answers.
The study finds that a type of white blood cell involved in immune responses (T-cells), as well as a type of protein (interleukin), play large roles in the development of MS. There are currently several drugs in development that target the immune system, including pharmaceuticals for leukemia and cancer. Alastair Compston of Cambridge University, who co-led this study, says, “We have implicated genes that are highly relevant to the actions of those drugs. It is now clear that multiple sclerosis is primarily an immunological disease. This is the way to nail this disease and get on top of it."
For their study, Compston and Peter Donnelly of Oxford University worked with 250 other researchers and studied the DNA from 9,772 people with multiple sclerosis. They then compared the DNA with a control group of more than 17,300 healthy people. Although there is no single gene that causes MS, the results suggest that people in the general population with a combination of these genetic links have an increased risk of developing the disease. Other environmental factors believed to be a risk include viruses, bacteria, and Vitamin D from sun exposure.
MS and other autoimmune diseases.A second study also sheds light on the genetics of MS. Developments published in the Public Library of Science journal,
PLoS Genetics, found that many of the genes linked to MS are also linked to other autoimmune diseases such as
Crohn's disease and type-1 diabetes.
“We have known for some time that many devastating diseases of the immune system must have common genetic causes," said Chris Cotsapas of Yale University, who led the PLoS study. "Now we have the outline of a map that tells us where we can look for common treatments."
As of right now, MS has no cure. But continuing scientific advances can give us better insight into the cause and development of this disease, and hopefully one day lead us to a way to prevent it.
