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Lafora Disease

Inherited progressive seizure disorder and dementia


Updated July 22, 2005

Lafora disease is one of five inherited progressive myoclonus epilepsy syndromes. Research has identified two genes, EMP2A and EMP2B on chromosome 6, as being associated with Lafora disease, and there may be other genes involved as well. How often Lafora disease occurs is not known.

A child with Lafora disease usually develops normally during the first decade of life. The symptoms of Lafora disease usually begin in late childhood or adolescence and become progressively worse over time. The symptoms include:

  • seizures
  • muscle spasms or jerks (myoclonus)
  • difficulty walking (ataxia)
  • quickly developing severe dementia
  • granules of accumulated carbohydrates known as Lafora bodies in nerve, heart, liver, muscle, and skin cells.

Diagnosis of Lafora disease is based upon the symptoms and the age at which they begin. In addition, a skin sample (biopsy) from the underarm can be examined, and a specific stain called PAS (periodic acid-Schiff) can identify Lafora bodies present in the cells. Genetic tests can identify mutations in the EMP2A or EMP2B genes.

There is no long-term treatment for Lafora disease. The seizures and myoclonus can be managed, at least in the beginning, with antiepileptic medications. However, the symptoms worsen as the young adult grows older, and many individuals with the disease do not survive beyond their thirties.

Research into mechanisms of disease
Research has identified the genes EMP2A and EMP2B as being associated with Lafora disease. It is known that EMP2A encodes two proteins, laforin and malin, but how these proteins cause the disease is not yet completely clear. It is known, though, that the lack of laforin and/or malin disrupts a complex biochemical pathway in cells that involves regulating the development of Lafora bodies. Further research into the exact mechanisms of Lafora disease is ongoing, with the future possibility of replacing the deficient proteins in nerve cells through gene therapy.

Information for this article was taken from:
- Chan, E.M., Ackerley, C.A., et al. (2004) Laforin preferentially binds the neurotoxic starch-like polyglucosans, which form in its absence in progressive myoclonus epilepsy. Human Molecular Genetics, 13(11), 1117-1129.
- Chan, E.M., Bulman, D.E., et al. (2003). Genetic mapping of a new Lafora progressive myoclonus epilepsy locus (EMP2B) on 6p22. Journal of Medical Genetics, 40(9), 671-675.
- Ganesh, S., et al. (2004). The carbohydrate-binding domain of Lafora disease protein targets Lafora polyglucosan bodies. Biochemistry and Biophysiology Research Communications, 313(4), 1101-1109.
- Minassian, B.A. (2001). Lafora’s disease: Towards a clinical, pathological, and molecular synthesis. Pediatric Neurology, 25(1), 21-29.
- University of California, San Diego. Research reveals mechanism involved with type of fatal epilepsy. Press release, dated 6/2/05.
- Wikipedia. (2005). Lafora disease

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