Lafora disease

Lafora disease

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 30834
ICD10 = ICD10|G|40|3|g|40
ICD9 = ICD9|333.2
ICDO =
OMIM = 254780
MedlinePlus =
eMedicineSubj =
eMedicineTopic =
MeshID = D020192

Lafora disease, also called Lafora progressive myoclonic epilepsy, is a fatal autosomal recessivecite journal |author=Ianzano L, Zhang J, Chan EM, Zhao XC, Lohi H, Scherer SW, Minassian BA |title=Lafora progressive Myoclonus Epilepsy mutation database - EPM2A and NHLRC1 (EPM2B) genes |journal=Hum Mutat. |volume=26 |issue=4 |pages=397 |year=2005 |pmid=16134145 | doi = 10.1002/humu.9376 ] extrapyramidal genetic disorder characterized by the presence of inclusion bodies, known as Lafora bodies, within the cells of neurons, heart, liver, muscle, and skin.

Most patients with this disease do not live past the age of twenty five and death within ten years of symptoms is usually inevitable cite journal |author=Minassan |title=Lafora's Disease:Towards a Clinical, Pathologic, and Molecular Synthesis |journal=Pediatr Neurol |volume=25 |pages=21-29 |year=2000 ] The disease is one of the five known genetic epilepsy syndromes that cause problems in the part of the brain , the occipital lobe, that controls vision. At this time there is no cure or treatment for this disease.

tatistics

Epilepsy occurs in one percent of all humans. Lafora Disease begins to show in children from 10 to 17 years old. There is no gender bias, both men and women are affected equally. This disease is extremely rare and usually occurs in humans in Eastern Europe and northern Africa. However, in the United States 200,000 people are diagnosed each year.

Causes

Lafora Disease is caused by the mutation of two genes, one being called EPM2A and the other is currently unknown. EPM2A is a gene that codes for a certain protein called laforin which is associated with keeping the inner membrane intact. A correlation has not been found between these mutations and seizures, but scientists believe that the mutation prevents sugars, such as glycogen, from going in and out of the cell. These molecules instead become "stuck" in the inner membrane where they are not used by the brain and other organs for energy. They also block other important molecules from entering the cell.

Lafora Bodies

The most distinguishing feature of Lafora Disease is the presence of dark spots called "Lafora bodies" within the cytoplasm, the viscous fluidic matrix inside of cells. These spots, while not normally present in the brain, are usually found in the neurons of the brain in patients affected by the disease.

Neurons are responsible for transmitting and receiving signals for the brain from other nerves in the body. Most important for Lafora Disease is the fact that neurons control muscle contration which is uncontrolled in those afflicted with the disease. Lafora bodies are composed of densely packed fiber like proteings and also have small granules along their outside. Current research has shown that cells do not use these foreign bodies, and they have no benefit for the body.

Presentation

The patients develop the first symptoms mainly during adolescence. Major problems are seizure, drop attacks, myoclonus (progressive myoclonic epilepsy), ataxia, and most importantly a quickly developing, progressive and severe dementia. At first they have lower than normal intelligence and often have neurological problems such as hallucinations and even blindness. Before symptoms appear children experience a childhood that is no different from their unaffected peers.

Eponym

This disease is named after Gonzalo Rodriguez Lafora (1887-1971), a Spanish neuropathologist. [WhoNamedIt|synd|3290|Lafora's disease] He published over two hundred papers on not only the disease named after him, but in several other areas of epilepsy and neurological disorders. Lafora became the first doctor to recognize small inclusion bodies in Lafora patients and named them Lafora bodies. Scientists would later call these bodies the main distinguishing feature of Lafora Disease from other epileptic conditions.

Diagnosis

Diagnosis is based on the demonstration of Lafora bodies within the sweat cells of the skin by an axillary skin biopsy examination. The inclusion bodies (which seem to comprise high levels of carbohydrates) are typically labeled by a specific stain called PAS (Periodic acid-Schiff).

Pathophysiology

Neither the origin of these inclusions, nor the exact mechanisms by which they cause the disease are known. Genetic studies indicate that mutations in the EPM2A gene encoding the protein laforin, and the NHLRC1 (EPM2B) gene encoding the protein malin are associated with the disease. Both genes are located on chromosome 6.

Prognosis

There is no treatment, and the therapy is mainly supportive and symptomatic. Although seizure and myoclonus can be controlled for a long period by using antiepileptic drugs, patients rarely survive beyond one or two decades due to the devastating effects of dementia and ataxia. One medication called Zonisamide has been shown to lengthen the life of those with the disease. This medication helps control and decrease the severity of the seizures these patients often experience.

External links

* [http://hmg.oxfordjournals.org/cgi/content/abstract/12/23/3161 Lafora disease - OxfordJournals.org]
* [http://www.chelseashope.org Chelsea's Hope- Lafora Children's Research Fund]

References


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