According to the United States National Institutes of Health (NIH), the signs and symptoms of Lafora disease generally appear during late childhood or adolescence. Prior to the onset of symptoms, affected children appear to have normal development although some may have isolated convulsions in infancy or early childhood.
The most common feature of Lafora disease is recurrent seizures. They generally become worse and more difficult to treat over time.
With the onset of seizures, people with Lafora disease often begin showing signs of cognitive decline. This may include behavioral changes, depression, confusion, ataxia (difficulty controlling muscles), dysarthria, and eventually, dementia. By the mid-twenties, most affected people lose the ability to perform the activities of daily living; have continuous myoclonus; and require tube feeding and comprehensive care.