When can a skin biopsy reveal Lafora disease

Lafora disease (LD) is a rare and particularly severe form of progressive myoclonic epilepsy (PME). It is an autosomal recessive hereditary disorder, with the responsible gene recently localized to chromosome 6q23-27. It is characterized by the onset, between the ages of 6 and 19, of generalized seizures followed by myoclonus. A major intellectual decline develops rapidly and progressively, eventually leading to dementia. Histological examination is essential for confirming the diagnosis of LD. The most practical procedure is a skin biopsy performed in the axillary region, allowing visualization of PAS positive inclusions within the excretory duct cells of the sweat glands-findings that are consistent with Lafora bodies. We report a clinical case of LD in a 16 years old adolescent girl and discuss the diagnostic challenges associated with this condition.