We report the case of a patient with trisomy 21 (T21) with late onset epilepsy. The electro-clinical features were of myoclonic jerks on awakening and generalised tonic clonic seizures, with generalised spike and wave on EEG, and a progressive dementia. As familial Alzheimer's dementia and progressive myoclonic epilepsy (Unverricht-Lundborg type) are both linked to the chromosome 21, this case may represent a distinct progressive myoclonic epilepsy related to T21.
myoclonic epilepsy; Down's syndrome; trisomy 21