{"id":1955,"date":"2020-07-09T21:00:00","date_gmt":"2020-07-10T01:00:00","guid":{"rendered":"https:\/\/nebula.org\/blog\/?p=1955"},"modified":"2021-04-16T18:18:34","modified_gmt":"2021-04-16T22:18:34","slug":"mthfr","status":"publish","type":"post","link":"https:\/\/nebula.org\/blog\/mthfr\/","title":{"rendered":"MTHFR \u2013 Why is there so much interest in this gene?"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

You may have heard about the buzz about the gene 5,10-methylenetetrahydrofolate reductase, or MTHFR <\/em>for short. <\/em>Thousands of studies have been published linking genetic variants, or mutations, in this gene, <\/em>to hundreds of medical conditions. These medical conditions include cardiovascular diseases, blood clotting issues, psychiatric disorders, developmental disorders, pregnancy complications, and cancer. However, the existing scientific data do not support most of the claims made about such associations.<\/p>\n\n\n\n

In this blog post, we break down the scientific literature to explain what we do know about MTHFR, <\/em>why testing for variants in this gene is likely not necessary, and why you should be wary of alternative medicine and supplement companies that are spreading misinformation and profiting from it. <\/p>\n\n\n\n

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The Science Behind <\/strong>MTHFR<\/em><\/strong><\/h2>\n\n\n\n

What is <\/strong>MTHFR<\/em><\/strong>?<\/strong><\/h3>\n\n\n\n
\"MTHFR
MTHFR produces 5-MTHF, the primary biologically active form of folate.<\/figcaption><\/figure>\n\n\n\n

MTHFR <\/em>is the gene that encodes for the enzyme 5,10-m<\/strong>ethylenetet<\/strong>rah<\/strong>ydrofolate r<\/strong>eductase. Enzymes are proteins that speed up chemical reactions in the body. The MTHFR enzyme helps convert a form of folate (5,10-methylenetetrahydrofolate) into a different form of folate (5-methyltetrahydrofolate), the latter of which is the primary biologically active form of folate. It plays a role in synthesis building blocks of proteins, otherwise known as amino acids. Specifically, this form of folate helps convert homocysteine to methionine. It has also roles in DNA damage response and the function of the nervous system.<\/p>\n\n\n\n

Common Variants in <\/strong>MTHFR<\/em><\/strong><\/h3>\n\n\n\n

There are a few common MTHFR <\/em>gene variants <\/em>that can decrease the activity of the enzyme. In fact, 40% of individuals in the general population<\/a> have one of these two common variants, <\/em>C677T and A1298C. The C677T variant specifically results in a 30-70% reduction in enzyme activity, likely due to the fact that the alanine to valine amino acid change makes the overall enzyme more heat-sensitive<\/a>. In contrast, A1298C results in a smaller reduction in enzyme<\/a> activity through an unknown mechanism.<\/p>\n\n\n\n

SNP ID<\/td>Major Allele<\/td>Minor Allele<\/td>Minor Allele Population Frequency*<\/td>Amino Acid Change<\/td><\/tr>
rs1801133(C677T)<\/td>C<\/td>T<\/td>34%<\/td>C (Alanine) > T (Valine)<\/td><\/tr>
rs1801131(A1298C)<\/td>A<\/td>C<\/td>31%<\/td>A (Glutamine) > C (Alanine)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

*Allele Frequency Aggregator (ALFA) Project<\/a><\/p>\n\n\n\n

It is important to note that not all common<\/em> genetic variants are disease-causing, especially if they are incredibly common in the human population. <\/strong>While individual C677T and A1298C variants do decrease enzyme activity, they generally do not cause health issues. Most individuals have no health issues (i.e. convert homocysteine to methionine) even if MTHFR <\/em>is not working optimally. In fact, most individuals that have a single variant appear to have normal, or non-elevated, homocysteine levels.<\/p>\n\n\n\n

In some cases, however, MTHFR activity may have decreased to very low levels, more likely in individuals with two copies of the MTHFR gene C677T variant. This can result in high homocysteine levels. Elevated homocysteine in the blood, otherwise known as homocystinuria, if left untreated, can result in abnormal blood clotting, brittle bones, and nearsightedness, and increased risk of having a child with a neural tube defect (spina bifida). Nevertheless, homocystinuria is rare<\/a>, with 1 in 200,000 to 335,000 affected individuals worldwide. Moreover, homocystinuria can result from genetic mutations in other genes, such as cystathionine-beta-synthase (CBS)<\/a>. Finally, homocystinuria is easily detectable, as the symptoms include seizures<\/a> and developmental delays. Thus, the condition is primarily diagnosed early in life and sometimes even as a birth defect.<\/p>\n\n\n\n