The MTHFD1 gene helps your body use folate, a B vitamin needed to make and repair DNA and support normal growth and blood cell production. If this gene does not work well, cells may struggle to divide and develop normally. Rare severe variants can lead to problems such as megaloblastic anemia, developmental delays, and immune system difficulties. More common variants are usually mild and may only slightly influence health.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or regulate activities in the body. Some genes provide the directions for making proteins, the parts of cells that do much of the work. Other genes mainly control when certain processes happen, where they happen, and how active they are. Together, genes affect how the body develops and works, and they can shape how you respond to food, stress, or medications. To explore this topic in more detail, you can learn more in the LearnHub.
Overview
MTHFD1Gene function
What if the gene works
Your cells use the MTHFD1 gene to process folate, a B vitamin. This helps make DNA building blocks and supports normal cell growth, repair, and early development.
Risk
What if the gene does not work
More disruptive variants in the MTHFD1 gene can impair folate processing and may lead to megaloblastic anemia, immune problems, and developmental differences. Milder variants may have smaller effects, while severe variants can cause earlier symptoms and broader features.
Treatment
What does that mean for your treatment
No treatment or medication choice is currently guided specifically by pathogenic variants in the MTHFD1 gene in routine clinical guidelines. The MTHFD1 gene is being studied in folate pathway research, including as a possible cancer biomarker and drug target.
Gene function
What if the gene works
Your cells use the MTHFD1 gene to handle folate, a B vitamin that carries small carbon units needed for everyday cell work. This is part of how the body uses folate to make DNA and other essential cell materials. It helps keep a steady supply of folate forms available, especially when cells are growing and dividing.
The MTHFD1 gene helps cells switch folate between several working forms. This lets folate carry small carbon units to the places where routine cell chemistry needs them.
Its protein supplies folate forms used to make key DNA building blocks. This supports normal cell division and tissue renewal, such as in the gut lining and blood-forming tissues.
It helps keep the cell’s folate pool in balance so different tasks can be supplied at the right time. That steady flow supports growth and routine turnover in many tissues.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, or how the body reacts to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. Sometimes, though, a variant can change a gene’s function more clearly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the MTHFD1 gene can affect folate processing by making the enzyme less stable, less active, or unable to complete one or more of its chemical steps. Milder variants may leave partial activity, while more severe loss-of-function variants can greatly reduce or abolish it. This can limit the cell’s supply of building blocks for DNA, and in people with two severe variants it is linked to earlier and broader features such as megaloblastic anemia and immune problems.
How variants are linked to conditions
Pathogenic variants in both copies of the MTHFD1 gene can cause a rare inherited folate-related condition, and finding these variants can confirm the diagnosis. People with this condition may have megaloblastic anemia (a type of anemia caused by abnormal red blood cell development), immune system problems, and developmental concerns. Some common MTHFD1 gene variants linked to conditions have also been associated with a higher chance of neural tube defects in population studies, but this reflects risk, not certainty.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are common throughout the general population. Most do not have a direct effect on health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. In other cases, a single well-characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risk related to the MTHFD1 gene itself. For many living with a change in MTHFD1, overall risk can also be shaped by the exact gene change and other genes, along with general health and nutrition, so personal guidance from a doctor or genetic counselor can help.
Inheritance of MTHFD1 variants
For families looking into how MTHFD1 gene variants are inherited, the well-established pattern for MTHFD1-related disease is autosomal recessive. This means a child usually needs to inherit one altered copy of the MTHFD1 gene from each parent to have the condition. Parents who each carry one variant are typically unaffected carriers, and with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child with two working copies. Sons and daughters are affected at the same rate.
What does my MTHFD1 result mean for my family?
For families with an MTHFD1-related condition, it usually means close relatives could also carry the same gene change, even if they feel well. Brothers and sisters may also be affected or be carriers, and parents are often carriers. Family members may want to talk with their doctor or a genetic counselor about what this result could mean in their family.
Genetic information
Genetic testing
How you find out about variants
MTHFD1 genetic testing usually uses a blood or saliva sample to look for variants in the MTHFD1 gene. A lab reads the DNA sequence and compares it with a reference sequence. Results may show no relevant variant, a benign variant, or one that can help explain health findings.
When should I consider getting a genetic test?
Testing for the MTHFD1 gene may be considered if a child has unexplained low blood counts, repeated serious infections, poor growth, or developmental concerns, especially when these happen together. It can also help when a close family member has a known MTHFD1 variant or a rare inherited folate-processing condition.
A genetic result is only one part of your health story
A genetic finding can provide useful insight, but how much it explains depends on the condition and on the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, influence how the body functions over time. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most helpful when considered alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, genetic results can also help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Small differences in genes can change how quickly a drug is broken down, how much of it reaches its target, or how strongly your body reacts to it. This helps explain why the same medication may work well for one person, do less for another, or cause more side effects in someone else. These differences are common and are one part of why treatment response can vary from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect a person’s response to medications. It studies the relationship between genes and drugs to help explain why treatments can work differently from one person to another. For many medicines, genes influence both how strongly a drug works and how the body processes it. This information can support more informed, individualized treatment decisions. To explore this topic further, you can learn more in the LearnHub.
Drugs influenced by the MTHFD1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so concerns about side effects, new symptoms, or how a medicine is working are best discussed with your doctor. MTHFD1 has been studied in folate-related medicines, including methotrexate, but the results are mixed and are not used on their own to guide routine treatment.