Late-onset myoclonic epilepsy in Down's syndrome (LOMEDS)

The aim of this paper is to report a patient with late-onset myoclonic epil epsy in Down's syndrome (LOMEDS) as a differential diagnosis of adult-onset progressive myoclonic epilepsies. A 55-year-old male with Down's syndrome (DS) is described who developed pro gressively frequent myoclonus and generalized myoclonic-tonic seizures (GMT Ss) at the age of 52. EEG recordings demonstrated background slowing and ge neralized polyspike-wave discharges occasionally associated with myoclonic jerks, leading to the classification of primary generalized epileptic myocl onus. Descriptions of late-onset epilepsy in DS patients are rare. However, a review of the pertinent literature revealed at least two other cases of elderly DS patients developing progressive myoclonic epilepsy after the ons et of dementia. We suggest that late-onset myoclonic epilepsy in Down's syndrome as charact erized here should be considered in the differential diagnosis of adult-ons et myoclonic epilepsies. LOMEDS apparently shares features with myoclonic e pilepsy in Alzheimer's disease (AD) and Unvenicht-Lundborg disease (ULD) ca used by a mutation on chromosome 21; Since life expectation of DS patients has markedly increased, LOMEDS may be more frequent than currently acknowle dged. (C) 2001 BEA Trading Ltd.