Contributor: Gordon K. Klintworth
Lafora disease (progressive myoclonic epilepsy type 2, OMIM # 254780) is an inherited autosomal recessive disorder in which grand mal seizures and/or myoclonic epilepsy start at ~15 years of age. A severe mental retardation develops rapidly and a psychosis is often associated. The course is progressive and dementia and blindness ensue. Death usually occurs within a decade of onset. The disease is named after the Spanish neurologist/neuropathologist Gonzalo Rodriquez Lafora (1886-1971) who first described the entity. The disease results from mutations in the EPM2A gene on human chromosome 6 (6q24). Intra- and extracellular Lafora bodies are present in the brain, heart, kidney, striated muscle and other tissues including the retina and myoepithelial cells of the secretory acini of apocrine glands. A diagnosis can be made with a skin biopsy. The differential diagnosis includes progressive myoclonic epilepsy type 1 and Hartung disease.
Aside from Lafora disease Lafora bodies are found in two other distict entities with neurologic manifestations: adult form of polyglucosan body disease [polyglucosan body disease - adult form] and amyotrophic lateral sclerosis with polyglucosan bodies.
In both Lafora disease and glycogenosis type IV Lafora bodies are found in liver cells.