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.
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).
Neither the origin of these inclusions nor the exact mechanisms by which they cause the disease are known. Genetic studies have recently disclosed that a gene (named as EPM2A) encoding the protein laforin is strongly associated with the disease.
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 are usually lost within one or two decades due to the devastating effects of dementia and ataxia.