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EPM2A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

EPM2A gene

The EPM2A gene provides instructions for producing the protein laforin, which is critical for regulating glycogen production and maintaining the health of neurons in the brain.

Normal Function

The EPM2A gene provides instructions for making a protein called laforin. Although this protein is active in cells throughout the body, it appears to play a critical role in the survival of nerve cells (neurons) in the brain.

Studies suggest that laforin has multiple functions within cells. To carry out these functions, laforin interacts with several other proteins, including malin (which is produced from the NHLRC1 gene). These proteins are part of complex networks that transmit chemical signals and break down unneeded or abnormal proteins. Additionally, laforin may act as a tumor suppressor protein, which means that it keeps cells from growing and dividing in an uncontrolled way.

Laforin and malin likely play a critical role in regulating the production of a complex sugar called glycogen. Glycogen is a major source of stored energy in the body. The body stores this sugar in the liver and muscles, breaking it down when it is needed for fuel. Researchers believe that laforin and malin may prevent a potentially damaging buildup of glycogen in tissues that do not normally store this molecule, such as those of the nervous system.

Health Conditions Related to Genetic Changes

Lafora progressive myoclonus epilepsy

More than 50 mutations in the EPM2A gene have been identified in people with Lafora progressive myoclonus epilepsy. Many of these mutations change single protein building blocks (amino acids) in the laforin protein. Other mutations delete or insert genetic material in the EPM2A gene. Almost all mutations in this gene prevent cells from producing any laforin or lead to the production of a nonfunctional version of the protein.

It is unclear how mutations in the EPM2A gene lead to the major features of Lafora progressive myoclonus epilepsy. Studies suggest that a loss of laforin prevents cells from regulating the production of glycogen. As a result, distinctive clumps called Lafora bodies form within many types of cells. Lafora bodies are made up of an abnormal form of glycogen (called polyglucosan) that cannot be broken down and used for fuel. Instead, polyglucosans build up to form clumps that can damage cells. Neurons appear to be particularly vulnerable to this type of damage. Although Lafora bodies are found in many of the body's tissues, the signs and symptoms of Lafora progressive myoclonus epilepsy are limited to the nervous system.

Researchers are uncertain how a loss of functional laforin contributes to the formation of Lafora bodies. However, a lack of this protein ultimately results in the death of neurons, which interferes with the brain's normal functions. The degeneration of neurons likely underlies the seizures, movement abnormalities, intellectual decline, and other neurological problems seen with Lafora progressive myoclonus epilepsy.

Other Names for This Gene

  • epilepsy, progressive myoclonus type 2, Lafora disease (laforin)
  • epilepsy, progressive myoclonus type 2A, Lafora disease (laforin)
  • EPM2
  • EPM2A_HUMAN
  • laforin
  • LD
  • LDE
  • MELF

Frequently Asked Questions

In the early stages, often beginning in adolescence, symptoms include subtle cognitive changes, such as difficulty with schoolwork or memory lapses, and mild myoclonus (sudden, brief muscle jerks). As the disease progresses, myoclonus becomes more frequent and severe, leading to drop attacks and generalized tonic-clonic seizures. In the late stages, patients experience significant cognitive decline, dementia, and loss of motor function, often becoming bedridden. The progression is relentless, and the disease is typically fatal within 10 to 15 years of symptom onset. What specific lifestyle and safety modifications are necessary for individuals with LPE to manage myoclonus and prevent injury?::Safety is the primary concern due to the risk of sudden drop attacks. Patients should avoid driving, swimming alone, or operating heavy machinery. Home modifications include removing sharp objects, installing grab bars in bathrooms, and using non-slip flooring to prevent falls. During meals, patients may need to use adaptive utensils or eat in a seated position to prevent choking if a myoclonic jerk occurs. Sleep hygiene is also critical, as fatigue can exacerbate myoclonus and seizures. Is there a specific dietary approach recommended for managing Lafora disease, and how does it relate to glycogen metabolism?::While there is no cure, some clinicians and researchers suggest a low-carbohydrate or ketogenic diet, as laforin deficiency leads to abnormal glycogen accumulation. Reducing carbohydrate intake may theoretically reduce the substrate for glycogen production, potentially slowing the buildup of pathological Lafora bodies in neurons. However, this must be carefully managed under medical supervision, as severe restriction can lead to malnutrition or worsen seizure control in some patients. It is not a standard treatment for all but is an area of active investigation and individualized care. How is Lafora progressive myoclonus epilepsy distinguished from other forms of epilepsy, and what role does genetic testing play in the diagnosis?::LPE is distinguished by the combination of progressive myoclonus, cognitive decline, and specific EEG patterns, but definitive diagnosis often requires genetic testing to identify mutations in the EPM2A gene. A skin biopsy can also be used to detect Lafora bodies, which are abnormal glycogen aggregates, though this is less common now with the availability of genetic tests. Early genetic confirmation is crucial for prognosis, family counseling, and ruling out other treatable forms of epilepsy that may mimic LPE in the early stages.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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