The MAST3 gene helps brain cells control signaling that supports normal communication, learning, and development. If a disease causing variant changes how this gene works, the brain may become more excitable than usual, which can lead to seizures and developmental differences. Many variants are harmless, while a few may change how the gene guides brain cell activity and are linked to developmental and epileptic encephalopathy, often with speech, movement, or learning challenges.
What is a gene?
Genes are stretches of DNA that give cells instructions for making molecules or guiding activities in the body. Some genes carry the code for proteins, which do much of the cell’s work. Others mainly regulate when, where, and how much certain functions take place. Taken together, genes affect how the body grows and works, and they can also influence how you react to food, stress, or medicines. For a deeper look at this subject, more information is available in LearnHub.
Overview
MAST3Gene function
What if the gene works
The MAST3 gene helps brain cells send and adjust signals by making a protein that modifies other proteins. This supports normal communication between nerve cells, especially in the outer part of the brain.
Risk
What if the gene does not work
Some people with variants in the MAST3 gene may develop childhood-onset epilepsy, often with developmental delay, speech or learning difficulties, and behavior differences. Effects can range from milder to more severe, depending on how strongly the variant changes MAST3 activity.
Treatment
What does that mean for your treatment
For a pathogenic variant in the MAST3 gene, no MAST3-specific treatment or drug selection approach is currently established. MAST3 is under study in epilepsy-related brain signaling, which may help guide future targeted therapies.
Gene function
What if the gene works
If you carry the MAST3 gene, your cells use it to keep internal signaling organized, especially where timing matters. In simple terms, MAST3 gene function is to help proteins pass along chemical messages in a controlled way. It also helps place signaling partners near each other so routine cell activity stays coordinated.
The MAST3 gene makes a protein kinase, a protein that adds small phosphate tags to other proteins. This helps cells switch important signals on or off at the right time.
Its protein has a docking section that helps bring other proteins together in the same place. This supports orderly signaling by letting cell partners meet and work as a group.
MAST3 belongs to a protein family that links signaling with microtubules (tiny internal support fibers). By doing this, it helps cells keep routine processes coordinated and stable.
What is a variant?
A genetic variant is a small 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 responds to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Research on how variants in the MAST3 gene affect protein function shows that many disease-linked changes swap one protein building block in the enzyme's signaling region. These variants can change kinase activity, meaning how strongly the protein adds control tags to other proteins, and some appear to make this signaling overly active even when less protein is present. Different variants can have different effects, and stronger changes may be linked to earlier or more pronounced epilepsy and developmental features.
How variants are linked to conditions
Pathogenic variants in the MAST3 gene can cause developmental and epileptic encephalopathy, a condition linked with seizures and differences in development, learning, or speech. In reported cases, seizures often begin in infancy or childhood, and the degree of developmental impact can vary. Some people with MAST3-related epilepsy have a milder picture, while others need broader neurologic support.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of being human and are widely found in the general population. Most do not directly affect health and instead reflect normal human diversity. For many genes, having a variant associated with a condition suggests a possible link rather than a confirmed diagnosis, especially when several genes and environmental factors play a role. In other cases, though, a single well-characterized variant in a specific gene may be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce health risk related to the MAST3 gene. In families with a disease-causing MAST3 change, risk is usually tied mainly to the genetic change itself rather than lifestyle or everyday exposures. Anyone worried about personal or family risk should speak with a doctor or genetic counselor.
Inheritance of MAST3 variants
For the epilepsy and developmental conditions linked to the MAST3 gene, how MAST3 variants are inherited is most consistent with an autosomal dominant pattern, meaning one altered copy can be enough to cause the condition. If a parent carries a disease-causing variant in the MAST3 gene, each child has a 50% chance of inheriting it. Many reported cases appear to result from a new (de novo) variant that was not inherited from either parent. Because the MAST3 gene is on chromosome 19 rather than a sex chromosome, this pattern is the same for males and females.
What does my MAST3 result mean for my family?
For families with a disease-causing change in the MAST3 gene, the pattern is generally dominant, so close relatives such as parents, brothers, sisters, and children may also carry the same change. In many reported families, the change is new in the child and is not found in either parent, so a parent is not always the source. Family testing can help clarify who else may be affected or who may have a chance of passing it on.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the MAST3 gene, doctors use genetic testing for MAST3 variants on a blood sample or cheek swab. A lab reads the gene’s DNA code and compares it with the usual sequence to look for changes. Results may identify a variant or show that no variant was found.
When should I consider getting a genetic test?
Genetic testing may be worth discussing if a child has seizures, especially if they start early or are hard to control, along with developmental delay or learning problems. Changes in the MAST3 gene have been linked to some epilepsy and brain development conditions, so testing can sometimes help explain the cause.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, though how much it explains depends on the condition and the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, influence how the body works over time. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result may offer 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 DNA can change how the body breaks down a drug, moves it through the body, or responds to it at its target. 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 someone who is more sensitive to it.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect a person’s response to medicines. It focuses on gene drug relationships to help explain why the same treatment may work differently from one person to another. For many medications, genes can influence both how strongly a drug works and how the body processes it. This information can help support treatment decisions that are more informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the MAST3 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work, so medication questions are best discussed with your doctor or pharmacist. It is especially worth checking in before starting, stopping, or changing treatment, or if side effects or poor symptom control become a concern.