The DHFR gene helps cells use folate, a B vitamin needed to make and repair DNA. In medicine, this gene is important because it helps regulate cell growth, especially in fast growing tissues like blood and the lining of the gut. If it does not work properly, the body may struggle to make healthy blood cells and support normal growth and brain development. DHFR is also known because several medicines, including methotrexate, work by blocking its activity.
What is a gene?
Genes are sections of DNA that give your cells instructions to make molecules or manage processes in the body. Some genes hold the instructions for producing proteins, the parts of cells that do much of the work. Other genes are mainly involved in controlling when certain processes happen, where they happen, and how strongly they take place. As a group, genes affect how the body develops and functions, and they can influence how you respond to food, stress, and medications. To look at this topic more closely, you can learn more in LearnHub.
Overview
DHFRGene function
What if the gene works
The DHFR gene helps your body use folate, a B vitamin. This supports making and repairing DNA and helps fast-growing cells, including blood cells, grow normally.
Risk
What if the gene does not work
More disruptive variants in the DHFR gene can cause a rare condition that affects folate use, leading to megaloblastic anemia, low immunity, and developmental delay or seizures. Milder variants may cause later onset or fewer features.
Treatment
What does that mean for your treatment
No treatment or management approach specifically tied to pathogenic variants in the DHFR gene is currently established in clinical guidelines. DHFR is still clinically important as a drug target because antifolate medicines such as methotrexate act on this pathway, and changes in DHFR activity are being studied for their role in treatment response and resistance.
Conditions associated with DHFR
Gene function
What if the gene works
Your cells need active folate every day to make DNA and support normal growth. The DHFR gene helps convert folate into a form the body can use for these jobs. Understanding what the DHFR gene does helps explain how cells keep up with routine repair and renewal.
One of the main jobs of the DHFR gene is to recycle folate into tetrahydrofolate, an active form cells can use. This gives cells a steady supply of folate for many everyday chemical steps.
Active folate from DHFR helps your cells make key DNA building blocks. This supports normal DNA copying when cells grow, divide, and replace older cells.
By supporting DNA production, DHFR helps steady cell renewal across the body. This is especially important in tissues that update often, such as blood and the gut lining.
What is a variant?
A genetic variant is a slight difference in the DNA sequence of a gene. These differences are common and help shape normal human diversity, including differences in appearance, metabolism, or how the body responds to environmental influences. Many variants have no obvious effect and are simply part of natural genetic variation. In some cases, though, a variant can change how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the DHFR gene can lower the amount or activity of the DHFR enzyme by changing its shape, reducing its stability, or weakening how it binds folate and NADPH. The effects of DHFR gene variants on folate processing can range from a mild drop in enzyme activity to very little working enzyme. More disruptive variants may lead to a stronger block in this pathway and, in rare DHFR deficiency, can be linked to earlier or more marked features.
How variants are linked to conditions
When people look up how variants in the DHFR gene are linked to conditions, the clearest association is a very rare inherited form of megaloblastic anemia due to DHFR deficiency. People with two disease-causing variants can have anemia, low folate in the brain, developmental delay, and seizures, although features vary. In this setting, finding pathogenic variants in both copies of the DHFR gene can confirm the diagnosis.
A variant is not necessarily a diagnosis
Variants are a usual feature of human biology and are found throughout the general population. Most do not directly affect health and instead represent normal human diversity. In many genes, carrying a variant associated with a condition points to a possible link rather than a clear diagnosis, particularly when several genes and environmental influences play a role. In some situations, though, one well-characterized variant in a particular 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 clearly increase or reduce health risk related to the DHFR gene itself. If you have a DHFR change on a test report or a family history that worries you, a doctor or genetic counselor can help put it in context.
Inheritance of DHFR variants
DHFR gene variants linked to DHFR deficiency are inherited in an autosomal recessive pattern. This means a child needs to inherit two disease-causing DHFR variants, one from each parent, to have the condition. Parents who each carry one variant are usually unaffected carriers, and with each pregnancy there is a 25% chance the child will inherit both variants, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither variant. In families asking how DHFR gene variants are inherited, this is the well-established pattern.
What does my DHFR result mean for my family?
For DHFR, family implications are usually discussed in a recessive pattern. This often means parents are healthy carriers, brothers or sisters may also be affected or may be carriers, and other close relatives could carry the same gene change. For many living with a DHFR-related condition, children are usually carriers unless the other parent also carries a DHFR change.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the DHFR gene, a lab can do genetic testing for DHFR variants using a blood sample or cheek swab. The test reads your DNA and checks for specific variants or, in broader panels, scans the whole gene. Results show whether a variant was found and how it is classified.
When should I consider getting a genetic test?
Genetic testing for the DHFR gene may be considered when a baby or child has severe, unexplained folate deficiency, a severe type of anemia, developmental delay, seizures, or immune problems, especially if similar findings run in the family. In this setting, testing can help confirm a rare inherited condition linked to DHFR.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it shows depends on the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. For some conditions, especially those affected by many genes, genetic information offers context rather than certainty and is best understood together with other parts of care. In other situations, a genetic result can give a clear answer. In areas such as medication response, genetic results can help put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in genes can change how the body absorbs, breaks down, transports, or responds to a drug. This is common and can help explain why the same treatment works well for one person, works less well for another, or causes more side effects in some people. Medication response is shaped by genes along with age, other health conditions, and other medicines.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medications. It looks at links between genes and drugs to understand why the same treatment may work differently from one person to another. For many medicines, genes can affect both how strong a drug’s effects are and how the body handles it. This information can support treatment decisions that are better informed and more individualized. If you want to learn more about this topic, you can find additional information in the LearnHub.
Drugs influenced by the DHFR gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication treatment, so questions about medicines, side effects, or treatment changes are best discussed with your doctor. Research on the DHFR gene has looked at how some people respond to folate-blocking medicines such as methotrexate, but these findings are not used routinely in everyday care.
History
Interest in the DHFR gene grew alongside the rise of folate based medicines in the mid 20th century. In recent decades, awareness of this gene’s role has grown. By the 1950s and 1960s, studies of antifolate drugs such as methotrexate made DHFR a key focus in cancer and blood disorder research. From these first observations, research expanded steadily. In the 1970s and 1980s, scientists showed that extra copies of the DHFR gene could appear in some cells, helping establish broader ideas about how genes can be amplified in cancer. That work also made DHFR a familiar gene in laboratory research and biotechnology, where it became a useful marker in cell studies.