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When the body doesn’t like myelin: multiple sclerosis


The list of bad things that can happen to your body doesn’t seem to be long enough, because your organism has found ways to harm itself in addition to the ones mentioned before. And one of them is multiple sclerosis.

It is one of the leading causes of disability in young people, without any trauma involved, affecting between 2.3 and 2.5 million people worldwide, with nearly a million of them in the United States in 2022. It is the primary cause of paralysis in Western countries.

An autoimmune disease that attacks the most common nervous system.

After epilepsy, it is the most common neurological disease in young adults. Quite an oxymoron, by the way. It is estimated to affect 1 case in every 1,000 individuals, with higher prevalence in women. In Northern Europe, the incidence is twice as high, and it is related to vitamin D deficiency.

It is one of those diseases that has decided to develop the bad habit of increasing its frequency worldwide in recent years.

Multiple sclerosis is (take a deep breath to say it without pausing) a chronic neurological disease caused by autoimmune and inflammatory factors characterized by the loss of myelin and axonal damage in the central nervous system. Oh, and there is a genetic predisposition, although environmental factors (often infections) also play a role in its development.

Moreover, a correlation has been found between the pathology and increased permeability in the intestine, allowing the passage of a greater number of substances (many of them undesirable) into the bloodstream. The culprits behind this atypical permeability are the intestinal microbiota (specific bacterial species) and gluten, which never tires of making lives bitter.

Although risk factors are known, the primary cause is still unknown today.

When the body doesn't like myelin: multiple sclerosis

It’s not hereditary, but it tries to be

How can we determine, in such an unknown disease, that there are genetic components? The usual trick is to assess heritability. Siblings of affected individuals have 10 to 20 times higher risk of developing the disease compared to unrelated individuals.

Multiple sclerosis is not considered hereditary as such. Descendants do not inherit the disease itself, but they can inherit alleles that predispose them to it and increase the risk of developing it compared to individuals without these specific gene forms.

While the environmental component has its presence here and its impact cannot be excluded, the fact that different ethnicities have different risks of developing the disease reinforces the idea of genetic sequences influencing the disease.

Therefore, multiple sclerosis would be a complex genetic disease like many other autoimmune diseases (such as type II diabetes). It would have a polygenic inheritance, where the risk of developing it is conditioned by a set of genes and their alleles, which would increase or decrease the risk of experiencing it.

Perhaps the most studied genetic component related to the disease is the HLA-DRB1 gene, which plays a role in the major histocompatibility complex (often linked to immune system diseases).

When we combine a high genetic predisposition for multiple sclerosis with the right environmental conditions, we get the outcome we don’t want. One of these environmental conditions is the previously mentioned vitamin D.

Infectious diseases are another risk factor, with the Epstein-Barr virus being prominent. Interestingly, multiple sclerosis patients have low levels of uric acid in their blood, which has led to the theory, through unknown methods, that this molecule somehow has a protective function. Suffering from gout as a defense against multiple sclerosis.

Yes, smoking is a risk factor. Think of any disease, and most of the time smoking is a risk factor.

You hit yourself

Although the onset of the disease involves many possible contributing factors, the disease process itself is straightforward: lymphocytes infiltrate the central nervous system and damage the axons and the myelin sheath that covers them, causing inflammation. That’s why it is considered an autoimmune disease.

In some forms of the disease, the immune system, not content with destroying the myelin, decides to go a step further and also destroy the oligodendrocytes, the cells that produce myelin.

It has been previously observed that there are failures in the blood-brain barrier, which malfunctions and allows for greater passage of immune cells.

During these early stages, inflammation is transient, and the tissue is capable of partial recovery and remyelination. However, over time, the activity of the immune system, both infiltrating cells and those within the nervous system itself, increases, and neurodegeneration becomes chronic and encompasses a larger extent. At this point, the disability experienced by the individual only worsens.

These damages cause neurons to lose the ability to transmit their nerve impulses, resulting in the classic symptoms of the disease. There is a relapsing-remitting variant where inflammation reaches a point of axonal transection, which leads to permanent lesions.

If there are many symptoms, there are many types

Since we’re talking about variants, the disease is classified into four or five groups depending on the source consulted.

1. Clinically isolated syndrome. It is the first manifestation. It lasts for at least 24 hours and occurs in the absence of fever and infections.

2. Relapsing-Remitting. It accounts for 85% of cases. There are severe and unpredictable attacks that last for weeks or months, followed by partial or almost complete remissions.

3. Secondary progressive. It occurs many years after a relapsing-remitting phase. 30-50% of patients evolve into this form, which involves progressive and gradual worsening.

4. Primary progressive. It affects 10-15% of patients. There are no attacks: once it appears, the degradation of nerve tissue is constant. It is more severe than the previous forms.

5. Progressive-relapsing. The worst villain of them all. It occurs in 3-5% of cases (fortunately) and, in addition to being constant, has periodic moments of increased intensity. Some experts consider it a more aggressive form of primary progressive.

When a disease has multiple factors causing it and different variants, it is not uncommon for there to be multiple forms of symptom presentation. The majority of cases consist of recurrent forms with low disability, although there are other more progressively disabling forms and severe cases that rapidly progress to disability.

As people love to give nicknames to everything, the nickname given to this condition is “the disease of a thousand faces.” The nickname is precisely because it manifests differently in each person. Additionally, symptoms vary depending on the affected areas of the nervous system.

If there are many symptoms, it complicates the diagnosis

The diagnostic approach when there is suspicion involves a neurological evaluation and a magnetic resonance imaging (MRI) to confirm demyelinating lesions in the nervous system.

There is no single test or marker to detect the disease.

Disease activity is measured based on the extent of tissue damage, disability caused, and the occurrence of relapses. These parameters can remain stable for long periods of time.

As it is a chronic disease, it accompanies you for the rest of your life. However, there are medications available to control cumulative damage and treatments for rehabilitation and symptom management.

The primary goal is to minimize disease activity, usually through medications that modulate it.

In addition to disease-modifying treatments, there are specific treatments for acute cases and different approaches for managing the symptoms caused by the condition.

The prognosis is challenging. One way to approximate it is by assessing disease progression during the first five years, which can help estimate the rate of progression over the following ten years.

If you want to assess your risk of developing the disease in case your immune system decides to dislike your nervous system, you can always try a tellmeGen Advanced DNA test. We like you.