The EPM2A gene helps control how cells store glycogen, the form of sugar your body keeps for later energy use. The protein made by this gene helps your cells keep glycogen well formed so it does not clump abnormally. When both copies of the gene do not work properly, abnormal glycogen can build up, especially in the brain, and this can cause Lafora disease, a rare inherited epilepsy. People with this condition often develop seizures, sudden muscle jerks, and gradual problems with movement, thinking, and daily activities during the teen years.
What is a gene?
Genes are sections of DNA that give cells instructions to make molecules or manage activities in the body. Some genes carry the code for proteins, which are the parts of cells that do much of the work. Others are mainly involved in regulating when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can also influence your response to food, stress, and medicines. More detail on this topic is available in the LearnHub.
Overview
EPM2AGene function
What if the gene works
The EPM2A gene helps cells manage glycogen, the stored form of sugar. Its protein helps remove extra phosphate from glycogen so it stays properly shaped and usable, especially in the brain, muscles, and other tissues.
Risk
What if the gene does not work
More disruptive variants in the EPM2A gene can cause Lafora disease, a progressive epilepsy with seizures, jerking movements, and worsening thinking and mobility. Milder variants may influence when symptoms begin and how strongly they affect daily life.
Treatment
What does that mean for your treatment
No EPM2A-specific treatment or management approach is currently established; care remains supportive, with antiseizure medicines chosen for symptoms rather than the EPM2A variant itself. Research in Lafora disease is exploring ways to reduce abnormal glycogen buildup, including treatments that lower glycogen synthase activity, but these approaches are not yet standard care.
Conditions associated with EPM2A
Gene function
What if the gene works
Your cells use the EPM2A gene to manage glycogen, the stored form of sugar used for energy between meals and during activity. Its protein, called laforin, checks the structure of this stored sugar and helps keep it usable. Understanding how the EPM2A gene works in the body can make it easier to see how cells handle everyday energy needs.
The EPM2A gene makes a protein that attaches directly to glycogen, your cells' stored sugar. This lets the cell act on glycogen right where it is kept.
Its protein removes small phosphate groups from glycogen. This helps stored sugar keep a normal shape and stay easier for cells to manage.
The EPM2A gene also helps control how glycogen is built and maintained. It works with partner proteins to keep sugar storage more orderly as cells store and use energy.
What is a variant?
A genetic variant is a slight alteration in a gene’s DNA sequence. These alterations are common and help shape the usual differences seen among people, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can more strongly change how a gene functions and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the EPM2A gene often weaken or eliminate laforin, a protein that helps control glycogen structure inside cells. This summary of how EPM2A gene variants affect protein function reflects a spectrum: some variants leave partial activity, while more severe variants cause near-complete loss of function and more buildup of abnormal glycogen. In Lafora disease, variants with less remaining function may be linked to earlier or more marked symptoms.
How variants are linked to conditions
Pathogenic variants in the EPM2A gene cause Lafora disease, a rare inherited form of progressive myoclonus epilepsy. This condition often starts in the teen years with seizures, sudden muscle jerks, and a gradual decline in thinking or coordination. EPM2A gene variants linked to Lafora disease usually need to be present in both copies of the gene to confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are common across the general population and are a routine feature of human biology. Most do not directly affect health and simply reflect natural variation among people. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, particularly when more than one gene and environmental influences play a part. In other situations, though, one well-described variant in a particular gene is enough to establish the diagnosis.
Are there things that can increase or change my risk?
For EPM2A, risk is mainly changed by inheritance: Lafora disease usually develops when a person inherits disease-causing changes in both copies of the gene. Having a family history of the condition or parents who are related by blood can raise the chance of this happening. There is not enough evidence to say that lifestyle changes lower this genetic risk.
Inheritance of EPM2A variants
Variants in the EPM2A gene linked to Lafora disease are inherited in an autosomal recessive pattern. This means a person usually develops the condition only if they inherit two altered copies of the EPM2A gene, one from each parent. Parents who each carry one variant are often unaffected carriers, and with each pregnancy there is a 25% chance the child will inherit both variants, which explains how EPM2A gene variants are inherited in families. Sons and daughters are affected at the same rate.
What does my EPM2A result mean for my family?
For families affected by changes in the EPM2A gene, close relatives may also carry the same gene change. Parents are often healthy carriers, and brothers or sisters may either have the condition or be carriers too. Other relatives, such as adult siblings of the parents, may also carry it, which can matter for family planning.
Genetic information
Genetic testing
How you find out about variants
To look for changes linked with Lafora disease, genetic testing for EPM2A variants analyzes DNA from a blood or saliva sample. Labs usually use sequencing to read the EPM2A gene and may add deletion and duplication testing to check for missing or extra pieces, helping clarify whether a disease causing variant is present.
When should I consider getting a genetic test?
Consider testing the EPM2A gene if someone develops seizures with sudden muscle jerks and a fast loss of school, memory, or daily skills, especially in the teen years. Testing can also help when Lafora disease runs in the family or when a close relative has already been found to carry an EPM2A change.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, but how much it reveals depends on the condition and the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, affect how the body functions over time. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is best interpreted 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 the genes involved in how the body absorbs, breaks down, or reacts to a drug can help explain why the same treatment works well for one person but less well for another. These differences are common and may influence how much benefit someone gets from a medicine or how sensitive they are to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way they respond to medicines. It studies gene and drug patterns to help explain why the same treatment can work differently from one person to another. For many drugs, genes can influence how powerfully a medicine works or how the body handles it. This information can support more informed, individualized treatment choices. More detail on this topic is available in the LearnHub.
Drugs influenced by the EPM2A gene
When should I seek medical advice?
There is not currently a broadly confirmed role for this gene in guiding medication choices, so questions about side effects, seizure treatment, or other medicine concerns are best discussed with your doctor.
History
Lafora disease was first described in 1911 by the Spanish neurologist Gonzalo Rodríguez Lafora, who identified the distinctive inclusions now called Lafora bodies in brain tissue. For many decades, doctors could recognize the condition from its clinical course and these tissue findings, but its genetic cause remained unknown. From these first observations, research expanded steadily. In the late 1990s, scientists mapped the condition to chromosome 6 and identified the EPM2A gene as one of its main causes, a major step for diagnosis and family studies. That discovery helped separate Lafora disease from other forms of epilepsy that can look similar early on. It also marked an important shift from describing the condition by what doctors could see under the microscope to confirming it through genetic testing.