MTHFR Gene Mutation: Symptoms, Testing and What to Do
MTHFR variants affect up to half the population. Here is what the gene actually does, what the common variants mean, and how to test for MTHFR in Australia without the hype.
Get an MTHFR TestMTHFR is a gene that produces an enzyme involved in folate metabolism and methylation. Two common variants, C677T and A1298C, can reduce enzyme activity. This affects how your body processes folate, B12 and homocysteine, with possible implications for cardiovascular health and pregnancy. An MTHFR test tells you which variants you carry, and because your genetics do not change, you only need to test once. You can get an MTHFR test in Australia without a GP referral.
- MTHFR is both a gene and the enzyme it produces, central to folate metabolism and methylation
- The two common variants are C677T and A1298C; around 40 to 50% of people carry at least one
- A variant on its own is not a diagnosis. Most carriers are perfectly healthy
- The most useful follow-up test is homocysteine, which shows whether the variant is having an effect
- You only need to test MTHFR once, because your genetics do not change
- You can test MTHFR in Australia without a GP referral
What is MTHFR?
MTHFR stands for Methylenetetrahydrofolate Reductase. It is both a gene and an enzyme. The MTHFR gene gives your cells the instructions to produce the MTHFR enzyme, which has one main job: converting folate into its active form, 5-methyltetrahydrofolate (also called methylfolate).
That active folate then drives the methylation cycle, one of the most important biochemical processes in the body. As Better Health Channel notes, folate is essential for healthy cell function and development. Methylation supports DNA synthesis and repair, gene expression, neurotransmitter production, detoxification and the clearance of homocysteine. When MTHFR enzyme activity is reduced, these processes can be affected to varying degrees, which is the whole reason the MTHFR gene gets so much attention.
The two common MTHFR variants
There are two well-studied variants of the MTHFR gene in the general population.
C677T
The most studied and most clinically relevant variant. Inheriting one copy (heterozygous) reduces enzyme activity moderately. Inheriting two copies (homozygous TT) reduces it more substantially. People with two copies are also more likely to have elevated homocysteine, particularly if their folate intake is low.
A1298C
A second common variant with a milder effect on enzyme activity on its own. It becomes more relevant in combination: people who carry one copy of C677T and one copy of A1298C (compound heterozygotes) can have reduced activity similar to C677T homozygotes.
Important perspective: roughly 40 to 50% of the general population carries at least one MTHFR variant. If you have been told you carry one, you are in the majority, not the exception. The variants raise certain risks in specific circumstances, but they do not cause disease in most carriers.
What MTHFR variants can affect
MTHFR variants alone do not cause illness in most people. Their relevance depends heavily on diet, lifestyle and other genetic factors. They become more meaningful in a few specific areas.
Cardiovascular health
Elevated homocysteine is the most reliably documented consequence of reduced MTHFR activity. When methylation cannot clear homocysteine efficiently, it can accumulate, and elevated homocysteine is independently associated with cardiovascular risk. This is the most evidence-supported reason to know your status, and the reason homocysteine is the key follow-up test.
Pregnancy and folate
MTHFR variants are part of the reason folate supplementation is universally recommended in pregnancy. Women with variants are sometimes advised to take methylfolate rather than standard folic acid. If you are planning a pregnancy, this is a conversation worth having with your GP or obstetrician.
Mood and methylation
Because methylation supports neurotransmitter production, reduced MTHFR activity has been studied in relation to mood. Some practitioners consider MTHFR and homocysteine in this context, though the evidence here is less settled than the cardiovascular link.
Who should consider an MTHFR test?
An MTHFR test is most useful if you fall into one of these groups:
- A history of recurrent miscarriage
- A personal or family history of early cardiovascular disease or blood clots
- A family member with confirmed MTHFR variants
- Previously elevated homocysteine
- Planning a pregnancy and wanting to inform your folate strategy
- Genuine curiosity about your own methylation, with the understanding that a variant is not a diagnosis
If none of these apply, an MTHFR test is not essential. Around half the population carries a variant and never experiences any consequence, because diet and lifestyle compensate.
Find out which variants you carry
Get an MTHFR TestWhat to do if you have an MTHFR variant
Knowing you carry a variant is just the start. What matters is whether it is actually affecting you, and that is something you can measure.
Test your homocysteine
This is the single most important follow-up. MTHFR variants matter most when they translate into elevated homocysteine. If your homocysteine is normal, your diet and lifestyle are compensating well. If it is raised, that is a clear, measurable target you can act on with your GP. The Homocysteine Blood Test measures this directly.
Consider methylated B vitamins
If you carry a variant, your body converts standard folic acid less efficiently. Methylfolate (the active form) bypasses that step. Methylated forms of B12 and B6 are sometimes used too. These are worth discussing with your GP rather than self-prescribing high doses, as a minority of people feel worse on high-dose methylfolate.
Eat whole-food folate
Natural folate from food is well absorbed regardless of MTHFR status: dark leafy greens, legumes, asparagus, broccoli, avocado and eggs are all good sources.
Get the complete methylation picture
The Methylation Profile tests MTHFR alongside homocysteine, B12 and folate, giving both the genetic predisposition and the current biochemical state in one panel. For the deepest read available privately in Australia, the Genetic Methylation Test is a home saliva kit that measures the broader methylation pathway.
How to get an MTHFR test in Australia
You do not need a GP referral to test MTHFR in Australia. The MTHFR Test checks both the C677T and A1298C variants. Because your genetics do not change, this is a one-time test.
- Buy your MTHFR test online
- Walk into any of Australia's 3,300+ Healius collection centres, no appointment needed
- Results delivered to your inbox within 24 to 48 hours
For the combined genetic and biochemical picture, the Methylation Profile bundles MTHFR with homocysteine, B12 and folate in a single panel.
Frequently asked questions
No. Around 40 to 50% of people carry at least one MTHFR variant, and most are perfectly healthy. A variant is a predisposition, not a diagnosis. Whether it has any real effect is best assessed by measuring homocysteine, which shows whether your body is compensating well.
Not necessarily. If your homocysteine is normal, your diet and lifestyle are already compensating, so methylated B vitamins are optional. If your homocysteine is raised, methylated forms may be more helpful. It is worth discussing with your GP rather than starting high doses on your own.
Generally no, for routine purposes. It is available privately through MediTests without a referral. Some specialists may order it through Medicare for specific clinical indications, such as recurrent miscarriage or suspected hereditary clotting conditions.
Once. Your genetics do not change, so a single MTHFR test gives you the answer for life. What can be worth re-checking over time is homocysteine, since that reflects your current biochemical state rather than your genes.
Most people with a variant still process folic acid, just less efficiently, and methylfolate is more readily usable. There is no strong evidence that folic acid at normal supplemental doses is harmful, but many people with variants prefer the methylated form. Discuss it with your GP, especially during pregnancy.
The MTHFR Test tells you which variants you carry. The Methylation Profile adds homocysteine, B12 and folate, so you see both the genetic predisposition and whether it is actually affecting your biochemistry right now.
- Frosst P, et al. A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase. Nature Genetics. 1995;10(1):111-113.
- Rozen R. Genetic predisposition to hyperhomocysteinemia: deficiency of methylenetetrahydrofolate reductase. Thrombosis and Haemostasis. 1997;78(1):523-526.
- Refsum H, et al. Homocysteine and cardiovascular disease. Annual Review of Medicine. 1998;49:31-62.
- Ray JG, Laskin CA. Folic acid and homocysteine metabolic defects and the risk of pregnancy loss. Placenta. 1999;20(7):519-529.
- Papakostas GI, et al. L-methylfolate as adjunctive therapy for SSRI-resistant major depression. American Journal of Psychiatry. 2012;169(12):1267-1274.
Test Your MTHFR Status in Australia
Buy online, walk into any of 3,300+ collection centres, results in 24 to 48 hours. A one-time test, no GP referral, no appointment, no consultation fee.
Get an MTHFR Test