As to what causes multiple sclerosis to attack one person and not another, doctors don’t have full answers to that question. The cause may be found in a genetic link, due to environmental issues, and lately there have been studies that show that MS may be due to some type of virus or viral infection.
There are immunological studies being done that study the body’s immune system and what could cause it to attack the substance surrounding the nerves, the definition of the disease. Some scientists are studying the patterns of MS and how it affects the population, this is called epidemiology, in order to find causes for the disease. Geneticists are also studying heredity and genetics in order to uncover causes for MS.
Uncovering a cause or causes for MS will help doctors and scientists figure out more effective ways to diagnose, treat, and eventually to cure the disease, or to even prevent multiple sclerosis from even occurring.
There are a few major theories on what causes multiple sclerosis. These include an immunologic cause, an environmental cause, a genetic cause, and an infectious or viral disease as the cause.
Immunologic
While it is generally believed that multiple sclerosis starts when the body mistakenly attacks the myelin, which protect the nerves found in the brain and spinal cord, it isn’t know why the immune system goes on the attack. Nor is it known what antigen causes the body’s defenses to attack what appear to be healthy cells.
There has been some progress made in the identification of which immune cells are responsible for starting the attack, and researchers have also figured out a few of the reasons causing these immune cells to attack. They’ve even been able to identify some of the receptors on the cells responsible for the attack that seem to be driven to destroy the myelin. But there are many questions about the body’s autoimmune system, including why it isn’t working correctly, how to stop the destructive process, or how to slow it down.
Environmental
We know that the farther someone lives from the equator, the more chances they have to get MS. Many believe this geographic pattern has more to do with the amount of sunlight a person is exposed to each day. The body uses sunlight to make vitamin D and those farther away from the equator are more likely to have a vitamin D deficiency. The vitamin D that comes from the sun is naturally produces by the body and vitamin D is believed to have a positive effect on the immune system.
It has even been discovered that if you are born in an area that has a low risk for developing MS, yet move to a high risk area before you are fifteen, then you will end up with the same risk factor of those born in the high risk area. If you move after you are fifteen then you retain your low risk probability. This discovery leads scientists to believe that environmental exposure before puberty to some agent may increase your chances of getting multiple sclerosis. Or the reverse could be true. If you are exposed to something in a low risk area before puberty, you risk for getting MS drops.
Other environmental research in regards to MS is the study of clusters. A multiple sclerosis cluster is the study of an area with higher number of MS cases than is expected. The cases must have occurred over a limited time period or in a very specific boundary. Studying MS clusters may eventually provide answers about the affect of toxins, trace metals, or diet on the disease.
Scientists are working to discover why multiple sclerosis is so prevalent throughout northern Europe, especially in Scandinavia and Scotland, and why in the United States there are more incidences of MS within the white race than in any other racial group.
Genetic
There have been common genetic factors found in families that have more than one person with multiple sclerosis. While this doesn’t mean that MS is a hereditary disease, it is believed that having a parent or sibling with MS may increase the risk for other individuals to contract the disease and that in part, MS may be inherited. If you have a sibling affected with MS, you will have a 2-5% risk for contracting multiple sclerosis.
There are some researchers who believe that if a person is born with a genetic predisposition for the disease, that exposure to an undiscovered environmental agent may cause the body’s autoimmune response, which causes MS. But the gene or genes responsible for allowing you to inherit MS have not been identified. Many researchers think there is more than one.
Infectious
There are many infectious diseases that are caused by different viruses, microbes, and bacteria that are known to cause inflammation and demyelination. Exposure to many of these diseases happens in childhood and tied with the fact that the body seems to form some geographical immunity by the age of fifteen, makes many scientists believe that some type of virus or infection may be one of the causes of MS.
Scientists are studying over a dozen infectious diseases may be able to cause MS. These include:
- Epstein-Barr or mononucleosis
- Varicella zoster, which causes chicken-pox
- Canine distemper
- Measles
- Herpes virus-6
- Chlamydia
- Pneumonia
So far no virus or infectious disease has been found to trigger the development of multiple sclerosis.
Doctors and scientists are studying many other factors to determine what might cause multiple sclerosis.