Posted by Kristal Louie on Fri, Jan 08, 2010 @ 08:54 PM
Spina Bifida, What does it have to do with MTHFR?
MTHFR stands for 5,10-methylenetetrahydrofolate reductase. For some of you those words are familiar because you have been told that you have one or two changes in that gene. For others, you have heard of the MTHFR gene but it is probably as foreign as a different language. Hopefully after reading this blog you will be a little more comfortable with the term and how it relates to Spina Bifida.
First some background information. The term "folate" is the natural Vitamin B9 found in one's diet and "folic acid" is the form of B9 that is found in supplements. Above is a diagram of how folic acid and folate are important to daily maintenance of your body, and therefore to a growing baby as well. Notice that folic acid and dietary folate enter the cycle at different points. Vitamin B9 is required for nucleotide biosynthesis and methylation of proteins, DNA and lipids. Nucleotide biosynthesis essentially means maintaining your genetic code in good condition by replacing damaged parts of your genetic code with new pieces. Methylation of proteins (building blocks for your body and machinery of your body), DNA (your genetic code) and lipids (fats) essentially means creating signals for how your body should work.
Looking at the diagram you can see that folic acid is converted into tetrahydrofolate (THF). THF is then converted into 5,10-methylenetetrahydrofolate (5,10-MTHF). MTHFR is the enzyme that changes 5,10-MTHF into 5-methyltetrahydrofolate (5-MTHF). As you can see MTHFR is only ONE of the many, many, many enzymes involved with Vitamin B9 metabolism. The enzymes I've shown in the diagram are only a handful of the enzymes involved in complete Vitamin B9 cycle and changes in any one of them may have an effect on Vitamin B9 metabolism.
Sometimes changes to the MTHFR gene can result in an inability to convert 5,10-MTHF into 5-MTHF. 5-MTHF helps convert homocysteine into methionine. Without 5-MTHF, an increase in homocysteine may occur. In some people, a build-up of homocysteine has health consequences such as vascular disease ( coronary artery disease, peripheral artery disease, arteriosclerosis, deep vein thrombosis, placental abruption leading to miscarriage). Theoretically changes in the MTHFR gene that cause increases in homocysteine may result in the above health risks.
HOWEVER often changes to the MTHFR gene do not result in health consequences. If you remember, dietary folate can be converted into 5-MTHF. That allows the cycle to continue by aiding the conversion of homocysteine to methionine. Changes in the MTHFR gene that do not result in increased homocysteine (due to dietary folate being converted into 5-methyltetrahhydrofolate) are not expected to increase health risks. However if a person cannot convert either dietary folate into 5-MTHF or folic acid to 5-MTHF, there could be an increase in homocysteine.
Currently changes in the MTHFR gene do not appear to have a strong association with an increased risk to have a child with Spina Bifida. Researchers have had a difficult time showing a strong association of Spina Bifida to a single gene like MTHFR. The researchers of the SB Genetics Research Project believe that it is likely several changes in not one, but many genes involved with Vitamin B9 metabolism that result in an increased risk to have a child with Spina Bifida. That is why we wish to include those women who have a change in the MTHFR gene and believe they know why they might have had a child with Spina Bifida. Hopefully, the topic of MTHFR and how it relates to Spina Bifida is a little clearer. The irony in that statement is that only looking at MTHFR will not make the understanding of the genetics of Spina Bifida clear.
Kristal
www.sbgenetics.org
support@sbgenetics.org