Multiple sclerosis (also known as MS) is a chronic disease that affects the central nervous system. The disease causes damage to a fatty substance called myelin, which serves as a coating that insulates the nerve fibers and enables electrical message transmitting.
The healthy function of our brain is based on transmission of electric signals, any disruption to this electrical stimulation results in damage to the brain’s function.
Types of MS
Multiple sclerosis is an umbrella term for several diseases, each characterized by a different pattern.
Relapsing-Remitting Multiple Sclerosis – this is the most common course of MS, that affects 85% of patients. It is characterized by “attacks” (also known as relapses) of symptoms that last several days to several weeks and then disappear fully or partially (remission). several months to several years can pass between relapses, these relapses cannot be predicted.
Secondary Progressive Multiple Sclerosis – within 10 years from their diagnosis, 50% of people with secondary progressive MS are diagnosed with a significant worsening of symptoms, characterized by symptoms that do not disappear or stabilize between relapses. This is a progressive condition in which symptoms eventually reach their maximum severity and become constant, without remissions.
Primary Progressive Multiple Sclerosis – occurs in only 10% of patients. People with this type of MS suffer from a progressive worsening of symptoms, without relapses. Usually, people with this type of MS experience their first relapse around age forty.
Progressive Relapsing Multiple Sclerosis – the rarest and most severe type of MS that occurs in only 5% of cases. This type is similar to primary progressive MS in which patients also suffer from severe relapses.
What causes MS?
The cause for multiple sclerosis is still unknown. It is most likely an autoimmune disease in which the immune system identifies myelin as a foreign factor that must be fought. However, the cause for this phenomenon is unclear. MS is most likely a multifactorial disease, which means that a variety of both genetic and environmental factors are required for it to develop.
The main theories that attempt to explain the reasons for developing multiple sclerosis are:
- A viral infection causes the immune system to become weak and identify myelin as the virus due to similarities in their antigens.
- A deficiency in vitamin D (a vitamin necessary for the immune system’s development) caused by a lack of exposure to sunlight.
- A lack of exposure to diseases during childhood.
- Certain mental factors could contribute to the onset of relapses, but the mechanism causing this reaction is still unclear.
The genetics of multiple sclerosis
It is important to understand that multiple sclerosis does not fall under the classic definition of an inherited disease. However, there is a connection between MS and genetics, demonstrated in research findings in this field. These studies, conducted on identical twins, show a thirty percent chance for one twin to develop this disease if their sibling develops it. However, there are most likely other factors involved.
It is important to note that MS is not a contagious or inherited disease, studies of this disease today have detected several genetic factors that could be responsible for multiple sclerosis.
Not only does the genetic factor play a secondary role in the development of this disease, but it is also a disease which involves many genes which have not yet been interpreted.