This post covers the history, epidemiology, genetic, and prevention of multiple sclerosis.
History of Multiple Sclerosis
Multiple sclerosis was first described, illustrated, and documented in 1838 by Sir Robert Carswell, a Scottish Professor of Pathology, but Multiple Sclerosis was not officially named until 1955 [1, 2].
Prevalence and Epidemiology of Multiple Sclerosis
The popular epidemiological notion is multiple sclerosis frequency increases with geographic latitudes .
Although some geographic locations such as Sardinia and Mediterranean regions have a higher frequency of multiple sclerosis cases. However, we still don’t understand why multiple sclerosis is more prevalent in these regions .
According to the Atlas: Multiple Sclerosis Resources in the World 2008 published by the World Health Organization (WHO), the global median estimated prevalence for multiple sclerosis is 30 per 100,000 individuals, while the global median estimated incidence of multiple sclerosis is 2.5 per 100,000 individuals .
The incidence of multiple sclerosis is low in childhood but drastically increases after 18 years of age, peaking around 25 to 35 years and declining after .
According to the Danish Multiple Sclerosis Registry, the median survival from the onset of the disease was about 10 years shorter and 3 times more likely at risk for death than the general population .
In 2015, about 18,500 individuals died from multiple sclerosis .
Despite these numbers, multiple sclerosis only marginally reduces the life expectancy of an individual but greatly diminishes the quality of life of that individual .
Multiple Sclerosis Genes
Different ethnic populations around the world have different prevalence and susceptibility to multiple sclerosis that cannot be explained by environmental factors alone .
Individuals with relatives affected by multiple sclerosis have a higher probability of developing the disease .
Identical twins have a 30% chance of both developing MS if one of them develop it. Whereas, non-identical twins or first-degree relatives have 3% risk .
First-degree relatives of individuals affected by multiple sclerosis are 10 – 25 times more likely to develop the disease than the general population .
Genetic variations are risk factors for multiple sclerosis. Several genetic regions have been implicated in the development of the disease (The most prevailing genes are the HLA genes which are contained in the major histocompatibility complex. The HLA genes are associated with susceptibility to the disease.) .
The complex relationship between genes and the diversity of those genes make associations difficult between identifying the relevant genetic variants and multiple sclerosis (extensive polymorphism and linkage disequilibrium) .
Despite the complexity and diversity of those genes, recent advances in genotyping have led to the discovery of at least 16 more genes (other than HLA) associated with susceptibility to multiple sclerosis .
Genome-wide association studies have found 52 risk alleles associated with the development of multiple sclerosis (HLA-DRb1 gene is the strongest correlation) .
Genes involved with Multiple Sclerosis:
The following are the genes associated with Multiple Sclerosis. Some genes are more problematic than others with regards to the risk factor.
- HLA-DRB1*1501 – rs3135388 A allele: This gene is the strongest genetic factor tied to multiple sclerosis. This gene is involved in the recognition of foreign material and pathogens by the immune system [15, 16].
- IL2RA – rs2104286 T allele: This gene is associated directly with the initiation of inflammation in the brain, which has a link with Multiple Sclerosis severity . Studies have shown that this gene is specific to those who have no history of multiple sclerosis in the family. This gene demonstrates that there is a significant difference between the sporadic and familial components of the disease .
- IL7R – rs6897932 allele: This gene is associated with patients who have developed progressive multiple sclerosis. This gene may potentially not be the cause of the disease but acts a determining factor for the course of the disease .
- CLEC16A gene2: This gene is excessively expressed in multiple sclerosis patients. It also has been described as a controller for the previously mentioned HLA class II producing gene in a large genetic pathway [19, 20].
- CD226 gene3: This gene is associated with severe cases of multiple sclerosis. This gene is essential in the activation of the regulatory T cells .
- CYP27B1 gene: This gene leads to a Vitamin D deficiency, which has a direct association with Multiple Sclerosis .
- SOCS1 gene: This gene suppresses the autoimmune responses (cytokines)of the human body, and an absence of the gene leads directly to inflammation. This is because SOCS1 is a key regulator of cytokine transmission and is correlated with both the CLEC16A gene and the DEXI gene [23, 24].
- RGS1 – rs2760524 allele: This gene shows both an association with multiple sclerosis as well as Celiac Disease. It encodes a molecule (G-protein signaling molecule) that is in charge of protein signaling in the development of the immune system .
- IL12A – rs4680534 allele: This gene forms an IL-12 cytokine that ameliorates the immune system through its role in T helper production .
- MPHOSPH9/CDK2API – rs1790100 allele: There is not much information for the MPHOSPH9 gene; however, the CDK2API does affect the level of RNA production. Specifically, this gene is an S-phase growth suppressor. A lower production of this gene is associated with the increased susceptibility of MS .
- PTGER4 – rs4613763 allele: This gene is down-regulated in MS patients cells and is involved with anti-inflammation .
- OLIG3/TNFAIP3 – rs9321619 allele: The OLIG gene is a significant factor of the nervous system development. The impairment of Olig3 shows a deficiency in neurons and thus a predisposition towards Multiple Sclerosis .
- ZMIZ1 – rs1250540 allele: This is a high disease risk gene that is decreased in autoimmunity responses. In MS specifically, this protein is reduced in production and can be caused by Epstein Barr Virus and Vitamin D deficiency .
- CXCR4 – rs882300 allele: This gene has been shown through magnetic resonance imaging to be found directly on inflammatory lesions in multiple sclerosis patients. It plays a significant part in a chemokine/receptor pair throughout the process of central nervous system inflammation .
Multiple Sclerosis Prevention
Multiple sclerosis is a complex disease with many contributing factors. Although some genetic factors cannot be adequately controlled, some environmental factors can be controlled.
Intake of vitamin D during childhood and adolescence can reduce the risk factors for multiple sclerosis .
UV radiation from sunlight has immunosuppressive effects that can also contribute to multiple sclerosis preventions .
Smoking is an important risk factor for multiple sclerosis. Cessation of smoking has contributed to a substantial number of multiple sclerosis preventions .
Reviews and Experiences with MS
Multiple sclerosis affected 2.3 million individuals globally in 2015 with a diverse range of symptoms and severity .
According to famous actress Jamie-Lynn Sigler during an interview with People, “I can’t walk for a long period of time without resting. I cannot run. No superhero roles for me.” When asked about stairs, the actress replied, “Stairs? I can do them but they’re not the easiest. When I walk, I have to think about every single step, which is annoying and frustrating .”
According to famous singer Walter Williams of the O’Jays, “I moped around the house for three or four weeks, really afraid, not knowing what was going to happen to me.” Walter Williams also states, “It just felt awful. . . . It would come and it would stay a year or two, then it would go away. That was the weirdest thing to me. I always thought it was something I was doing that made it go away, or made it come back. This went on for years. I found out later that I had nothing to do with it — it’s just one of the characteristics of MS .”
This post is part 3 of a 3-part series.