The “Broken” Gene, in Plain Words

The short answer

Slower is not broken

The MTHFR gene helps your body switch on folate, vitamin B9. Many people carry a version that does this more slowly. That is common and, for most people, not a problem. Your genes show a possibility. A blood test shows what is actually happening.

What the gene does

Folate, and the switch

Folate is vitamin B9. You find it in leafy greens, beans, lentils, asparagus and avocado. Your body uses it to make new cells and healthy red blood cells.

Before your body can use folate, it has to turn it into its active form, called methylfolate. The MTHFR gene makes the enzyme that does the last step. Think of it as a switch.

How common it is

Half of us carry it

The best-known version is called C677T. In the Netherlands:

• ~4 in 10carry one copythe switch works at about two-thirds of normal speed
• ~8 in 100carry two copiesthe switch works at about one-third of normal speed

There is a second, milder version called A1298C.

Read it carefully

Why “broken” is the wrong word

Slower does not mean switched off. The US Centers for Disease Control and Prevention (CDC) states that people with an MTHFR variant can process all types of folate, including folic acid. Most people who carry it have normal folate levels.

The link to energy

Low folate can leave you tired

If your body runs low on folate, it can't make enough healthy red blood cells. This is called folate-deficiency anaemia, and constant tiredness is one of its main signs. Low vitamin B12 and low iron can cause the same tiredness.

Carrying the gene is not proof that you are low. Many things can make you tired, so talk to your doctor if tiredness doesn't go away.

Already switched on

What methylfolate is

Methylfolate is folate that is already in its active form, so it skips the slow step. That is why some doctors suggest it, especially for people with two copies. Whether it matters for you is a question for a blood test and your doctor, not for a gene report.

What you can do

Measure, don't guess

The American College of Medical Genetics and Genomics (ACMG) says routine MTHFR testing has little clinical use. For people with two copies, it recommends measuring homocysteine in the blood instead. The blood tests worth asking your doctor about:

• Homocysteine. A substance in the blood that tends to rise when folate, B12 or B6 aren't keeping up. It shows whether a slower switch actually matters for you.
• Folate (serum or red blood cell folate).
• Vitamin B12.
• Iron stores (ferritin) and a full blood count, if you feel tired.

Planning a pregnancy? Folic acid advice still applies to you, even if you carry an MTHFR variant (CDC). Talk to your doctor or midwife.

What this does not mean: it does not mean methylfolate is useless, and it does not mean folic acid is dangerous for carriers. It does not tell you to start or stop any supplement. That is a conversation for you and your doctor.

Our approach: at Evmara we start with what your body shows, not what a gene might suggest. Measure first, then decide.