Methylation cycle and MTHFR gene mutation

Methylation Cycle
Methylation is when one molecule passes a methyl group, which is a carbon atom linked to three hydrogens, to another molecule. When this happens it creates reactions that are critical to our survival. Methylation effects are more noticeable in cognitive issues, the gut and the detoxification system. It also has a hand in the production of neurotransmitters and the function of the brain. With this being the case, with methylation defects and mutations you can start seeing ADHD, depression, anxiety, autism, and other behavioral issues, as well as chronic fatigue, infertility, and miscarriages.

Gene Expression
One of the most important functions of methylation is that it regulates gene expression as well. Methylation controls turning genes on and off, like a light switch. A methyl group attaches to a gene and changes the way that the gene expresses itself. This change is known as DNA methylation.
Over the last few decades, we have come to learn that environmental factors like stress, sleep, diet, and toxins causes the molecular changes that are not encoded in DNA. As we all know, genes are passed down from parent to child. But this change in the genetic code has a lot to do with what our parents were exposed to, what we were exposed to in utero, and also what we are currently exposed to throughout our lives. More recent studies have shown that both a mother and father’s diet before, and at the time of conception affect their child’s health. Even their grandchildren are affected by this. It isn’t only as the mother goes through pregnancy that a good diet and healthy lifestyle should be followed. This puts a whole new responsibility on us to take care of our bodies and eat a good diet for our health so that it could be passed on to future generations.
Dr. Chris Kresser gives a great example to help understand this genetic change. He says, “Depending on the time of year that they’re born, baby voles (mice) are either born with a thick coat of hair or a thin coat. If they’re born at a time of year where the weather is warmer, there will be an epigenetic change that changes the expression of the genes that code for hair production, and they’ll be literally born with a different coat depending on what time of year they’re born. In fact, more accurately, the gene for the thick coat is always there for these voles, but it’s just either turned on or off depending on the level of light that the mother senses in her environment, so once again that’s a way that the environment interacts with gene expression.”

As you can tell, methylation is an important process for the body. But what can cause the methylation process to go wrong and affect how a gene turns on and off? There are two different reasons. The first one is environmental factors. Once again this is the environment, gut health, diet, exposure to toxins, and stress. The second one is genetics. There are a lot of enzymes in the complex methylation cycle. But it’s when mutations happen in certain genes that lead to decreased activity of the enzymes which causes reduced activity of methylation.
The most important enzymes in the methylation cycle are known as MTHFR, methylenetetrahydrofolate reductase. Quite a mouthful isn’t it? The function of the MTHFR gene is to produce the MTHFR enzymes. However, if the MTHFR gene is altered, or mutated, the enzymes produced become distorted. The enzyme function depends on the shape. It is just like a key. If the grooves aren’t exactly right, then it cannot unlock the door.
Yes, these mutations are passed down and there is no way to completely cure it, but remember that another one of the affects are environmental factors. For example, if we take two different people with the same genes and mutations, and the first one has gut infections, doesn’t sleep well, are extremely stressed out, poor diet, and they don’t exercise? And then let’s take a look at the other person that has a healthy gut biome, good diet, getting their sleep, managing stress, and taking the time to exercise. Logic concludes that both of these people will have very different methylation capacity due to the influence of environmental factors on the genetics and mutations.

Dr. Chris Kresser. “RHR: Methylation – What is it and why should you care?”
Dr. Lynch.