Familial encephalopathy with neuroserpin inclusion bodies is a recently described neurodegenerative disease that is responsible for progressive myoclonic epilepsy or presenile dementia. In a French family with the S52R mutation of the neuroserpin gene, progressive myoclonic epilepsy was associated with a frontal syndrome. The typical cerebral inclusions (Collins bodies) were abundant in the frontal cortex and in the head of the caudate nucleus but spared the cerebellum.