What Causes Chronic Fatigue Syndrome? - Part III: Genetics

Note: This is the third article in an ongoing series. Make sure to check out the following articles once you’re finished with this one!

What Causes Chronic Fatigue Syndrome? – Part I: Understanding Fatigue
What Causes Chronic Fatigue Syndrome? – Part II: The Epstein-Barr Virus & Other Infections
What Causes Chronic Fatigue Syndrome? – Part IV: Hormones
What Causes Chronic Fatigue Syndrome? – Part V: A Functional Medicine Approach

Did the genes mom and dad passed on to you set you up to develop chronic fatigue syndrome?

Or, is there more to fatigue than just a bad set of genes?

Conventional medicine is reductionist in nature. Meaning that researchers and medical doctors are always zooming-in to best identify the abnormality that is the sole cause of an illness. In chronic fatigue syndrome, the process is no different. In my previous article, I discussed the connection infectious viruses and yeasts play in chronic fatigue.

With no crystal clear cause of chronic fatigue connected to infection, could your genes hold the key to whether you’ll develop chronic fatigue syndrome?

Genetics 101

Genes

You, me, and everyone else in this world has the same set of 20,000 genes. The reason I have red(ish) hair is due to a slight variation in my genes. We all have a hair color gene. But the slight variation in my gene expresses my hair as red(ish) in color. Yours may express as brown, blonde, black etc.

One way to think of DNA is like an instruction manual for your cells. Without it, your cells wouldn’t know how to express themselves. I reckon it would be quite chaotic without DNA instructing your cells on what to do.

You’ve probably seen pictures of a DNA strand. It’s called a double helix but it looks more like swirling ladder. The rungs of your DNA ladder are called bases.

Did you know: DNA has its own alphabet?

The four letters of the DNA alphabet are A, T, G, and C. A always pairs with T and G always pairs with C. These pairs are what make up the rungs on your DNA ladder.

Your DNA ladder is organized into many different pieces. One of those pieces is called a chromosome. You have 23 pairs of chromosomes. Other organisms have different numbers of pairs – for example, chimpanzees have 24 pairs. No, more chromosomes do not mean you’re better or more advanced. Chickens, for example, have 78 chromosomes. Whereas blue whales only have 44. (1)

If you break chromosomes down further, you get short segments of DNA which we call genes. Imagine your DNA to be the script of a play or movie, the genes are the way the actors and actresses act out the part(s). The script (or, DNA) tells the actors (genes) how to express a given scene. For example, if you have blonde hair, it is because the genes you inherited from your parents are instructing your hair follicle cells to make blonde strands of hair.

SNPs

Do you remember how your body makes new cells?

New cells are created through something called cell division. This is when an existing cell divides itself into two, creating a new cell. In order to ensure the new cell is a welcome member of your body, the DNA in the new cell needs to be identical. To ensure this happens, when a cell is dividing, it copies its DNA so the new cell will have the same instruction manual as other cells.

Unfortunately, this dividing process is not perfect. Sometimes, cells make mistakes while in the process of dividing. These “goofs” cause slight variations in your DNA at specific locations. This variation is called an SNP (pronounced “snips”).

SNPs can create all sorts of genetic differences in people. SNPs are like a rogue scriptwriter snuck in and wrote a few different lines in your movie script (DNA). This changes the way the actors (genes) act out a particular scene. SNPs can alter your physical appearance, your immune system, and even your overall health.

While more information is needed, SNPs could by what makes you more susceptible to chronic fatigue syndrome.

SNPs and chronic fatigue

In 2016, a comprehensive study analyzed over 600,000 SNPs to see if any of them were related to chronic fatigue syndrome. There were over 400 SNPs that showed to be correlated with a genetic “risk” of developing chronic fatigue syndrome. This finding shows that there is not one single gene or genetic connection that predisposes one to chronic fatigue syndrome. There is no chronic fatigue gene.

Instead, there are hundreds of small SNPs that could make you more susceptible to developing CFS. One of these was an SNP on the CLEC4M gene. This gene helps your immune system identify and remove harmful infections including hepatitis C and human immunodeficiency virus. Those with an SNP on this gene may make one more susceptible to infection and possibly suffer chronic fatigue as a result of this infection. (2)

Other SNPs found on a gene called the TCA affect your immune system. More specifically, these SNPs affect the way your immune system responds to infection and foreign invaders. Certain SNPs on this gene can increase the likelihood of developing an autoimmune disease. (3) The researchers believed that this gene and SNP may contribute to the development of chronic fatigue syndrome.

To summarize, yes, SNPs seem to play a role in chronic fatigue. But much more research is required before we can make conclusive statements about their relation to CFS.

Is chronic fatigue genetic?

Studies have shown that chronic fatigue may very well have an inheritable or genetic component. (4) There is a higher risk of developing chronic fatigue syndrome if you have a first-degree relative who also suffers from it. A first-degree relative is either your parent, sibling, or child.

If your mom has chronic fatigue syndrome, you’re at a much higher risk of developing it yourself. Same goes if your brother has chronic fatigue syndrome. If your cousin or either grandparent has chronic fatigue syndrome, you’re also at an elevated risk (when compared to the general public) though not at as high of a risk as with a first-degree relative. (5, 6)

In studies done on identical and fraternal twins with chronic fatigue syndrome, pairs of identical twins were more likely to develop chronic fatigue syndrome than fraternal twins. Since identical twins share identical DNA and genes, this illustrates that chronic fatigue has at least some genetic component to the development of the disease. (7)

One part of your genetic code is called the Human Leukocyte Antigen (HLA) complex. The HLA complex is responsible for the regulation of the immune system in humans. (8) In 98% of those with celiac disease, the HLA DQ II and/or HLA DQ VIII complexes are active. These complexes are also active in ~50% of the general population. (9) This illustrates that celiac disease has a genetic component but is not caused entirely by genetics.

Similarly, in chronic fatigue syndrome, those diagnosed with the disease have an increase in antigens to HLA DQA1 and the HLA DR4. (10) HLA types are inherited from our parents. While we still have lots to learn, those with HLA antigens are more likely to develop autoimmune diseases and/or chronic fatigue syndrome. (11)

Another study showed a genetic connection between your immune system and chronic fatigue syndrome. If you were to get a viral infection, your body would begin producing something called cytokines. Cytokines are a group of proteins released by your immune system in response to an infection. While more research is needed, it seems that those with chronic fatigue syndrome exhibit a significantly elevated level of circulating cytokines. It is thought that this elevated level is due to a genetic component. (12) Researchers are not sure why this occurs. But it could help to explain why those with chronic fatigue feel sick. Their body is reacting as though it is fighting an infection.

To summarize, chronic fatigue syndrome has a strong genetic component. But genes don’t cause chronic fatigue syndrome. Genes only predispose you to develop it.

Like most modern diseases, the genetics from your parents load the gun (so to speak). But it is your environment that pulls the trigger. Meaning that the food you eat, your exposure to chemicals/toxins, stress levels, etc. all play a role. The genes mom and dad passed your way are not a life sentence. They can be altered by the way you interact with your environment.

At the time of this writing, it is clear that much more research is needed. There are initial correlations and connections being made between chronic fatigue and genetics. But at this time, the research is in its infancy.

Do you need help improving your fatigue?

For a deeper dive into other possible causes of chronic fatigue syndrome, check out the below links: