Contrary to popular believe, MTHFR does not stand for motherf***er. It stands for methylenetrahydrofolate reductase, hence the acronym, as no one wants to say methylenetrahydrofolate reductase more than once.
The focus of this post is to directly address what professional societies recommend regarding (1) the utility of MTHFR genetic testing and (2) the implications of MTHFR genetic test results.
Back in the day, investigation of MTHFR variants focused on rare but harmful changes associated with inborn errors leading to severe hyperhomocysteinemia (i.e., high levels of homocysteine in one's blood) and homocystinuria (i.e., homocysteine in one's urine). Only 50 or so patients have been diagnosed worldwide with this type of deficiency. Clinical symptoms displayed by these MTHFR-deficient patients include developmental delay as well as various neurological and vascular problems, such as seizures, thromboses, and vascular lesions.
Take Home Message #1
Severe hyperhomocysteinemia and homocystinuria is super rare, not the focus of this post, and honestly, is most likely not affecting you.
However, the identification of two common variants, i.e. polymorphisms, (C677T and A1298C) brought into question the potential association of these specific variants with a range of complex disorders including vascular disease, cancer, cleft lip and palate, neural tube defects, glaucoma, pregnancy complications, and mental health diagnoses.
How common is common? Approximately 40% of Americans have one copy of a common variant (heterozygous); approximately 10% of this population have two copies of a common variant (homozygous).
Take Home Message #2
Hyperhomocysteinemia is multifactorial, meaning that lots of genetic factors, not only if and what changes you have in the MTHFR gene, and environmental factors work together to lead to high levels of homocysteine in your blood.
Individuals who are MTHFR polymorphism homozygotes may have hyperhomocysteinemia, usually to a mild or moderate degree of uncertain clinical significance. Why is it uncertain? Because initial and subsequent studies on a whole slew of conditions reached very different conclusions.
At the end of the day, only one fact remains: the potential impact and the degree of impact of MTHFR common variants is a lot like politics and religion - everyone has a different view and it is unlikely any one person will change the other side's view. But here's the important part, so pay attention:
Take Home Message #3 - i.e, The Mother of All Take Homes
In general, medical experts do not recommend genetic testing for common MTHFR variants.
WHY?
The American College of Medical Genetics advises against genetic testing for the common MTHFR variants since their presence or absence should not affect medical management. Elevated plasma homocysteine has been associated with an increased risk of coronary artery disease, venous thrombosis, and pregnancy complications.
What this is saying is that elevated homocysteine levels in one's blood can increase the risk for certain disorders, NOT whether or not you have any variants in the MTHFR gene. Because again, having a variant in this gene is only one of many many things that can increase the level of homocysteine in your blood.
If you have not yet pursued MTHFR genetic testing
And you have a personal concern or your healthcare provider has a clinical suspicion for elevated homocysteine levels, a fasting plasma homocysteine level may be ordered by your healthcare provider. It is not recommended that you pursue MTHFR genetic testing as the results of this testing will not impact how you are treated.
If you have pursued MTHFR genetic testing
And you have a personal concern or your healthcare provider has a clinical suspicion for elevated homocysteine levels, a fasting plasma homocysteine level may be ordered by your healthcare provider.
To lower homocysteine levels, your healthcare provider will usually recommend taking vitamin B supplements that include folic acid, which is a form of folate. You might have read or heard that folic acid is not safe if you have one or two copies of the MTHFR C677T gene change. This is not true. Even if you have one or two copies of this gene change, your body can safely and effectively process folic acid supplements and all types of folates in food.
In today's world of medical advancements, it is tempting to claim that the cause of one's symptoms is genetic. And many times, it is. But the truth is that while genetics has come a long way, we still have an even longer way to go; especially when it comes to the complex disorders that have been associated with the common MTHFR variants.
And when we think of it that way, aren't most genes motherf***ers.
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