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Lafora Disease
Sunday, 14 August 2005
Sunday, 14 August 2005
Myoclonic Epilepsy of Lafora; Progressive Myoclonus Epilepsy with Polyglucosan Bodies; Lafora Body D

What

Lafora disease (LD) is a rare genetic disorder that occurs in children or adolescents, resulting in progressive decline of mental function. It is a member of the family of diseases known as progressive myoclonus epilepsies (PMEs). PMEs are characterized by progressively worsening seizures. Lafora disease attacks the nervous system by inappropriately depositing sugars into cells of the brain (as well as cells in the liver, muscle, and skin). These deposits, known as Lafora bodies, interfere with the brain’s normal functions, causing seizures, visual hallucinations, and dementia. Individuals with Lafora disease usually develop normally until their early teens, when they begin to have seizures that eventually become worse and more frequent.

Who

Lafora disease seems to affect males and females equally. It is most common in the Mediterranean countries of Southern Europe, Northern Africa, and the Middle East; but worldwide it remains very rare. It is the most common teenage-onset progressive myoclonus epilepsy, with symptoms most commonly first appearing between the ages of 11 and 18. Some children, however, may begin showing signs of LD by the age of 6. If multiple children in a single family have the disease, later children will likely exhibit symptoms at a younger age than did the first child in the family to develop the disease.

Signs and Symptoms

A teenager with Lafora disease usually develops quite normally for the first 10 years of his/her life. Many of these individuals, however, had occasional seizures earlier in infancy or childhood. Most commonly, the first symptom of LD is a generalized tonic-clonic seizure, a seizure that affects the entire body and consists of extreme muscle tension and rapid rhythmic muscle contractions. The first sign of disease may also be another type of seizure (such as a seizure brought on by a flickering light), temporary blindness (usually also associated with a localized seizure), visual hallucinations, depression, or poor performance in school.

Possible Causes

Lafora disease is a genetic disorder with autosomal recessive inheritance, meaning that a child can only get the disease if both of his/her parents are carriers for the mutant gene. Even when both parents are carriers, however, a child only has a 25% chance of getting the disease. The vast majority of individuals with LD have mutations of either the EPM2A or EPM2B genes. These two genes are both located on chromosome 6 and code for laforin and malin, two separate proteins with unknown function. There seems to be a third gene that can cause Lafora disease when it is mutated, and further research on this gene is currently underway. These mutations are what cause the seizures and other symptoms of the disease. LD cannot be spread from one individual to another, and nothing can be done to cause or prevent a child from developing it.

Diagnosis

Lafora disease is diagnosed based on the results of a biopsy of an individual’s skin, liver, muscle, or brain. Due to the invasiveness of muscle, liver, and brain biopsies, samples are most commonly taken from the skin. When examined under a microscope, biopsy samples taken from an individual with LD have evidence of abnormal sugars, known as Lafora bodies. The presence of Lafora bodies within a sample of brain, muscle, liver, or skin tissue is diagnostic of Lafora disease. It is also possible to do genetic tests to detect the genes that are known to cause LD, but these tests are very expensive and may not catch all cases of the disease since it is believed that additional genes that have not yet been identified can cause LD.

Treatment

At this time, no cure exists for patients with Lafora disease. Early on in the disease, antiepileptic medications (drugs to prevent/limit seizures) may be helpful. As the disease progresses, however, these medications usefulness become ineffective. Individuals with LD should be closely followed by a pediatrician, a neurologist, and other specialists as needed to ensure that symptoms are controlled and the patient is kept as comfortable as possible. The assistance of a genetics counselor is also helpful for families who wish to have additional children (since the disease is inherited). It is possible that in the future, bone marrow transplantation and/or gene therapy will be effective in treating Lafora disease by fixing the dysfunctional genes. At this point, though, neither of these types of therapy has been effective.

Prognosis

In most cases, after they have their first seizure, an individual with Lafora disease will begin to have seizures more and more frequently; and these seizures will become increasingly difficult to treat. Early on in the course of the disease, individuals with LD often develop problems with their balance and speech. Confusion and emotional disturbances are also common early on in the course of the disease. As the disease progresses, the nervous system becomes more dysfunctional. This leads to an increase in the frequency and severity of seizures and may also lead to muscle spasticity (abnormally increased muscle tone, almost as if the individual was constantly flexing his/her muscles). Over time, Lafora disease causes problems with movements, so that those with advanced LD are usually wheelchair-dependent. Status epilepticus – continuous seizure activity for an extended amount of time – is common. Most individuals with Lafora disease have regressed to a non-responsive (“vegetative”) state by their mid-20s, and most die within 10 years after diagnosis. Death is most commonly due to pneumonia or complications related to the degeneration of the nervous system.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.

Weblinks

Lafora Body Disease Research Talk
This website is a discussion board about Lafora disease and contains a great deal of easy-to-read information about the LD, contact information for other families affected by the disease, and several other related links.

About.com: Lafora Disease
This website contains some basic, understandable information about Lafora disease, as well as several helpful links and the citations for a few medical journal articles about LD (though these will probably be less helpful than other more basic resources).

Google Search for Lafora Disease

References and Sources

Minassian BA (2001). Lafora’s Disease: Towards a Clinical, Pathologic, and Molecular Synthesis, Pediatric Neurology, 25(1), p 21-9. Minassian BA (2002). Progressive Myoclonus Epileps with Polyglucosan Bodies: Lafora Disease, Advances in Neurology, 89, p 199-210.