Two siblings with Lafora disease (LD) are described: one with epilepsy, myoclonus, EEG abnormalities, severe dementia and many Lafora bodies (LBs) in muscle and skin tissue; the other with myoclonus, epilepsy, EEG abnormalities and LBs in muscle and in skin tissue, without dementia. The findings suggest that the diagnosis of LD by skin and muscular biopsy is possible in the early stage of the disease, when there are myoclonic epilepsy and EEG abnormalities, before the onset of dementia.