The MTHFR gene provides instructions for creating an enzyme called methylenetetrahydrofolate reductase, which plays a role in the body’s methylation process. This process is involved in many bodily functions, including converting folate into its active form, 5-methyltetrahydrofolate (5-MTHF). Variations, or mutations, in this gene can affect how efficiently the body processes certain vitamins and amino acids, leading many individuals to consider genetic testing.
Understanding the MTHFR Gene Mutation
The MTHFR gene produces an enzyme necessary for converting folate (vitamin B9) into its biologically active form, L-methylfolate (or 5-MTHF). This active form is used in the methylation cycle, a series of biochemical reactions throughout the body. The MTHFR enzyme also helps convert the amino acid homocysteine into methionine, used for protein production and other important compounds.
Common mutations in the MTHFR gene, specifically the C677T and A1298C variants, can reduce the enzyme’s efficiency. For instance, individuals with two copies of the C677T variant may experience up to a 70% reduction in enzyme activity. Having one copy of the C677T variant can lead to about a 30-35% reduction. The A1298C variant typically has a less significant impact on enzyme function alone, but when combined with a C677T mutation, overall efficiency can be further impaired.
Why Consider Testing for MTHFR?
Individuals or their healthcare providers may consider MTHFR gene testing for various reasons, often due to clinical suspicion or health concerns. One common indicator is elevated homocysteine levels in the blood. High concentrations of this amino acid have been linked to potential damage to blood vessels and an increased risk for blood clots, heart disease, and stroke. While elevated homocysteine can have other causes, an MTHFR gene mutation could be a contributing factor.
Other conditions that might prompt MTHFR testing include a family history of MTHFR mutations or health issues like recurrent miscarriages. Studies have explored associations between MTHFR variants and neurological or psychiatric conditions, such as depression, anxiety, bipolar disorder, and schizophrenia, though research is ongoing and sometimes conflicting. Testing may also be considered if a healthcare provider prescribes certain medications, such as methotrexate, as the MTHFR protein helps the body use this medicine.
Types of MTHFR Gene Tests
Testing for MTHFR gene mutations can be done through a healthcare provider or via direct-to-consumer (DTC) genetic testing kits. Clinical genetic testing is typically ordered by a doctor and involves collecting a blood sample or a buccal (cheek) swab. These samples are sent to specialized laboratories for analysis, specifically looking for the common C677T and A1298C variants.
The process for clinical testing usually begins with a consultation where a healthcare professional assesses the patient’s medical history and symptoms to determine if MTHFR testing is appropriate. Once the sample is collected, it is processed in a laboratory to identify the specific genetic variants. Results from these tests are generally considered accurate and are interpreted by medical professionals in the context of a patient’s overall health.
Direct-to-consumer genetic testing kits offer an at-home option for MTHFR gene screening. These kits typically involve collecting a saliva sample, often using a sterile cotton swab rubbed inside the cheek. The sample is then mailed to the company’s laboratory for analysis. While convenient and accessible, DTC test results may have limitations and might require confirmation with a clinical test for medical decision-making. Results from DTC tests are often delivered within 5-6 business days after the sample is received.
Understanding Your MTHFR Test Results
MTHFR test results generally indicate the presence and type of gene variants. A “wild type” result means no common mutations were found in the MTHFR gene, indicating typical enzyme activity.
If you have a “heterozygous” result, you inherited one copy of a mutated gene and one normal copy. For example, “heterozygous C677T” indicates one copy of the C677T mutation, which may result in approximately a 30-35% reduction in enzyme activity. “Heterozygous A1298C” typically has a less significant impact on enzyme function.
“Homozygous” means you inherited two copies of the same mutated gene, one from each parent. For instance, “homozygous C677T” (also written as C677T/C677T or TT) can lead to a more significant reduction in MTHFR enzyme activity, potentially up to 70%. A “homozygous A1298C” result (A1298C/A1298C or CC) generally has a less pronounced effect on homocysteine levels. A “compound heterozygous” result means you inherited one copy of each common mutation, such as C677T and A1298C. This combination can also lead to reduced enzyme activity, potentially around 55%.
Managing MTHFR Gene Mutations
Once MTHFR gene mutations are identified, management typically involves lifestyle and dietary adjustments to support the body’s methylation processes. This often includes increasing the intake of natural folate from foods like leafy greens, liver, and legumes. Individuals with MTHFR mutations are often advised to avoid synthetic folic acid, commonly found in fortified foods and many supplements, as their bodies may have difficulty converting it to its active form.
Supplementation with methylated forms of B vitamins, such as L-methylfolate (5-MTHF) and methylcobalamin (methyl B12), is frequently recommended to bypass the gene’s impaired function and support healthy folate levels. It is important to consult a healthcare professional for personalized advice and a tailored management plan. They can help determine appropriate dosages and monitor homocysteine levels, if necessary, to optimize health outcomes.