The MTHFR gene plays a role in a fundamental bodily process called methylation. This process involves the transfer of methyl groups between molecules and is involved in DNA repair, gene expression, neurotransmitter production, hormone metabolism, energy production, and detoxification. Understanding your MTHFR test results can provide insights into how your body processes folate and related compounds.
Understanding the MTHFR Gene and Testing
The MTHFR gene provides instructions for creating an enzyme called methylenetetrahydrofolate reductase. This enzyme is responsible for converting 5,10-methylenetetrahydrofolate (MeTHF) to 5-methyltetrahydrofolate (MTHF), the active form of folate (vitamin B9) the body uses.
Genetic variations in the MTHFR gene can alter the enzyme’s activity, potentially affecting the body’s ability to process folate and regulate homocysteine levels. An MTHFR gene test typically uses a blood sample to look for two common variants: C677T and A1298C. MTHFR testing provides information about these genetic predispositions, but it is one piece of an individual’s overall health and genetic makeup.
Decoding Your MTHFR Test Report
When you receive your MTHFR test report, it will describe your genetic makeup for the MTHFR gene. Everyone inherits two copies of each gene, one from each parent. The report indicates the presence or absence of common variants at specific positions.
One common term is “wild type” or “normal,” meaning no variants were detected on that copy of the gene. For the C677T variant, a normal result is C/C, indicating two copies of the cytosine (C) allele at position 677. Similarly, for the A1298C variant, a normal result is A/A, meaning two copies of the adenine (A) allele at position 1298.
If your report indicates “heterozygous,” you have one copy of the variant allele and one copy of the normal allele for a specific gene location. For example, a C677T heterozygous result is C/T, indicating one normal C allele and one variant T allele at position 677. For the A1298C variant, a heterozygous result is A/C, indicating one normal A allele and one variant C allele at position 1298.
A “homozygous” result is two copies of the same variant allele for a specific gene location. For the C677T variant, a homozygous result is T/T, signifying two variant T alleles at position 677. For A1298C, a homozygous result is C/C, signifying two variant C alleles at position 1298. These variant names refer to a change in the DNA sequence at a particular position (677 or 1298) where one nucleotide (C or A) is replaced by another (T or C).
Interpreting the Impact of MTHFR Variants
The presence of MTHFR gene variants, especially C677T and A1298C, can influence the efficiency of the MTHFR enzyme. Individuals with one copy of the C677T variant (heterozygous C/T) show a reduction in enzyme activity to about 65% of normal. If an individual has two copies of the C677T variant (homozygous T/T), enzyme activity can be significantly reduced, to as low as 25-30% of normal function. This reduction can lead to increased levels of homocysteine, an amino acid, in the blood.
For the A1298C variant, a heterozygous A/C genotype has a minor impact on enzyme activity. However, individuals with two copies of the A1298C variant (homozygous C/C) may experience a reduction in enzyme activity to approximately 60% of normal. Two copies of A1298C are not associated with increased homocysteine levels.
Some individuals may inherit one copy of the C677T variant and one copy of the A1298C variant, a condition known as compound heterozygosity. This combination can also lead to decreased enzyme function, with a reduction in MTHFR enzymatic activity by approximately 55%. The actual impact of these variants can differ among individuals, as other genetic and environmental factors play a role in overall enzyme function and methylation processes.
Practical Steps After Receiving Results
After receiving your MTHFR test results, consulting a qualified healthcare professional is a sensible next step. Your doctor, a genetic counselor, or a registered dietitian can discuss the results in the context of your complete medical history and overall health. They can help interpret how these results might relate to your personal health concerns and guide you on appropriate actions.
MTHFR variants are common, and having them does not automatically mean you will experience health issues. Many individuals with MTHFR variants do not require specific interventions unless they have elevated homocysteine levels or other related health symptoms. Lifestyle considerations can also play a role in supporting methylation pathways.
General recommendations may include incorporating a diet rich in natural folates, found in leafy green vegetables, legumes, and certain fruits. While some sources suggest avoiding synthetic folic acid if you have MTHFR variants, others emphasize that people with MTHFR variants can process all forms of folate, including folic acid. Your healthcare provider may also recommend specific vitamin B supplements, such as methylfolate, to support homocysteine metabolism.